JP2607308B2 - Ink jet printer head and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an ink jet printer head that discharges ink from nozzles by changing the volume of an ink chamber, and a method of manufacturing the same.

<Related Art> Ink jet printers have recently been receiving attention because they can record on plain paper with low noise and are easy to colorize. The inkjet recording system is roughly classified into a continuous system and an on-demand system. The on-demand system which does not require ink collection and is suitable for miniaturization and cost reduction of the apparatus is becoming mainstream. This on-demand method includes:
There are mainly a thermal method and a piezoelectric method, and both are different depending on the ink ejection method. The thermal method utilizes the boiling of the ink due to heat generation, and the piezoelectric method utilizes the volume change of the ink chamber due to the vibration of the piezoelectric element. The piezoelectric type has the advantage that the physical properties of the ink are less restricted than the thermal type and the size of the ink droplet can be controlled by the applied voltage. However, low frequency response,
There is also a disadvantage that the arrangement pitch of the piezoelectric elements cannot be reduced.

By the way, the processing accuracy of the ink jet nozzles used for discharging these inks is an important factor that directly affects the print quality of the ink jet printer. Particularly, in the case of a multi-nozzle having a plurality of nozzles, depending on the size of each nozzle, Since the print dot diameter of the character changes, a problem arises in that uniform printing cannot be performed due to variations in the size of each nozzle.

Japanese Patent Application Laid-Open Nos. 54-146633 and 55-94660 disclose a method of forming a groove in a silicon substrate by using a silicon anisotropic etching technique in order to improve nozzle accuracy. FIG. 7 shows an ink jet printer head disclosed in these publications. FIG. 1A is a top view, and FIG. 1B is a cross-sectional view along AA '.
As shown in the figure, the conventional ink jet printer head includes a first silicon substrate 70 in which a groove of a nozzle portion 71, an ink chamber 72, and a pressure chamber 73 is formed, and a second thin substrate 74 in which no groove is formed. The piezoelectric body is formed on the second thin substrate 74.
75 is attached. This conventional ink jet printer head is manufactured as follows. First, a first silicon substrate 7 having a (100) plane
After a nozzle pattern is formed with an etching mask at 0, the nozzle groove is formed by anisotropic etching, so that the nozzle groove is formed into a V-shaped groove having a depth of 30 to 100 μm in which both sides are formed by the (111) surface. It is manufactured to become.
At the same time, the grooves of the ink chamber 72 and the pressure chamber 73 are formed by etching. At this time, the depth of the groove of the pressure chamber and the ink chamber is about
It is formed to 150 to 300 μm. As described above, in the above method, when forming the nozzle groove and the grooves of the pressure chamber and the ink chamber having different depths, both side surfaces of the nozzle groove are formed (111).
The dimensional accuracy of the nozzle groove is maintained by utilizing the low etching rate of the surface.

JP-A-58-51162 discloses a method in which a nozzle section, a pressure chamber, and an ink chamber are separately formed and then joined.

<Problems to be Solved by the Invention> However, Japanese Patent Application Laid-Open Nos. Sho 54-146633 and 55
In -94660, since the nozzle groove, the ink chamber, and the pressure chamber groove are formed in the same silicon substrate, the nozzle groove is over-etched, and the dimensional accuracy is deteriorated. That is, when anisotropic etching is performed on the (100) plane silicon substrate, the etching of the V-shaped groove surrounded by the (111) plane is automatically stopped when the formation is completed. It should be, but actually (11
1) On the surface, the etching proceeds very slowly,
A deviation from the design value will occur. The print dot diameter is
Since the size varies depending on the size of the nozzle, if the dimensional accuracy of the nozzle portion is deteriorated, there have been problems in that the print density is not uniform, and in the case of a multi-nozzle, print unevenness occurs.

Further, it is preferable that the direction of the nozzle is exactly paired with the direction of the <110> crystal axis, but in fact, perfect coincidence is impossible. FIG. 6 is a graph showing the relationship between the azimuth angle of the crystal of the silicon substrate, the misalignment angle between the mask pattern and the nozzle width, the horizontal axis represents the misalignment angle of the mask pattern with respect to the azimuth angle of the substrate crystal, and the vertical axis represents the etching. This is the nozzle width after. As shown in the figure, as the misalignment angle between the azimuth and the mask pattern increases, the nozzle width increases and the dimensional accuracy also deteriorates.

Also, as in JP-A-58-51162, if the nozzle section and the pressure chamber and the ink chamber, which are the other ink flow paths, are separately formed and then combined, extra parts and an assembling process are required, and production Worse.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet printer head in which the dimensional accuracy of a nozzle portion is high and the nozzle portion can be integrally formed with an ink chamber and a pressure chamber.

<Means for Solving the Problems> In order to achieve the above object, an ink jet printer head according to the present invention is characterized in that a nozzle groove is formed in an ink jet printer head in which an ink flow path is formed by subjecting a silicon substrate to groove processing. A substrate of the first silicon substrate, comprising a first silicon substrate and a second substrate forming an ink flow channel groove behind the nozzle groove, wherein the nozzle groove and the ink flow channel groove are continuous. The surface and the substrate surface of the second silicon substrate are overlapped.

In the method of manufacturing an ink jet printer head according to the present invention, a (100) crystal silicon substrate is used as the first silicon substrate, and a V-shaped nozzle groove is formed in the first silicon substrate by anisotropic etching. An ink jet printer head is manufactured by a step of forming, a step of forming an ink flow path groove in the second silicon substrate, and a step of overlapping and connecting the grooves inside each other.

It is preferable that the nozzle direction of the nozzle groove coincides with the <110> crystal direction of the first silicon substrate.

<Operation> In the ink jet printer head of the present invention, since the first substrate having the nozzle grooves formed therein and the second substrate having the pressure chambers and the ink chamber grooves are formed, the nozzle grooves have high dimensions. It is possible to form with high precision.

Furthermore, in the manufacturing method of the present invention, since a silicon substrate having a (100) crystal plane is used as the first substrate, a V-shaped groove is formed when the nozzle portion is formed by anisotropic etching. Then, both side surfaces of the V-shaped groove are formed.
1) Since the crystal plane plays a role of stopping etching, a nozzle groove with high dimensional accuracy can be formed.

Further, after forming a nozzle groove in the first substrate and forming a pressure chamber and an ink chamber groove deeper than the nozzle groove, the grooves are overlapped on the inner side with each other to form the first substrate and the second substrate. These ink channels can be integrally formed.

Embodiment 1 Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a structural view of an ink jet printer head according to the present invention, wherein FIG. 1 (a) is a plan view and FIG.
A 'sectional view, FIG. (C) is BB ′ sectional view, and FIG.
Is a CC ′ cross-sectional view, 1 is a first silicon substrate having a (100) crystal plane, 2 is a second silicon substrate,
Reference numeral 3 denotes a piezoelectric body, 4 denotes a nozzle portion, 5 denotes a pressure chamber, 6 denotes an ink chamber, 10 denotes a thermal oxide film, and 13 denotes a through hole for a piezoelectric body.

FIGS. 2 (a) to 2 (j) are process diagrams showing a manufacturing process of the first ink jet printer head.

First, the nozzle portion 4 shown in FIG. 1B was formed on a first silicon substrate by the following method.

In FIG. 2A, a thermal oxide film 7 was formed on both surfaces of the first silicon substrate 1 having a (100) crystal plane, and a nozzle pattern was formed thereon using a photoresist 8. Next, in FIG. 2 (b), the thermal oxide film 7 was removed in a nozzle pattern by etching with a hydrofluoric acid buffer solution of HF: NH ₄ F = 1: 6. At this time, it is desirable that the direction of the nozzle coincides with the <100> direction of the first silicon substrate in order to increase the dimensional accuracy of the groove. Next, FIG. 2 (c)
In the above, a groove of the nozzle portion 4 was formed on the first silicon substrate 1 by performing anisotropic etching with a 25 wt% KOH aqueous solution. The anisotropic etching was stopped when the V-shaped groove was formed. The depth of the nozzle groove is controlled in accordance with the etching mask pattern width, and is usually selected from 20 to 60 μm.
A 39 μm nozzle groove was formed. Then, FIG. 2 (d)
In the above, after the thermal oxide film 7 was once removed with hydrofluoric acid, the thermal oxide film 7 was formed again as a protective film on the entire surface.

Next, the pressure chamber 5, the ink chamber 6, and the through hole 13 for the piezoelectric body shown in FIG. 1B were formed on the second substrate 2 by the following method.

In FIG. 2 (e), a thermal oxide film 7 is formed on both surfaces of the second silicon substrate 2, and a photoresist 8 is used thereon to form a pressure chamber 5, an ink chamber 6, and a through hole 13 for a piezoelectric body. A pattern was formed. Next, in FIG. 2 (f), HF: NH ₄ F
The thermal oxide film 7 is removed in a pattern of the pressure chamber 5, the ink chamber 6, and the through hole 13 for the piezoelectric body by etching with a hydrofluoric acid buffer solution of = 1: 6. Next, in FIG. 2 (g),
The grooves of the pressure chambers 5 and the ink chambers 6 and the piezoelectric through holes 13 were formed on the second silicon substrate by performing anisotropic etching with a 25 wt% KOH aqueous solution. The etching was stopped when the piezoelectric through-hole was formed. At this time, the depth of the grooves of the pressure chamber 5 and the ink chamber 6 is the thickness of the wafer.
It was 150 μm, which is half of 300 μm. Thereafter, in FIG. 2H, the thermal oxide film 7 was once removed with hydrofluoric acid, and then the thermal oxide film 10 was formed again as a protective film.

Next, in FIG. 2 (i), the first substrate 1 on which the nozzle portion 4 is formed as described above, and the second substrate on which the pressure chamber 5, the ink chamber 6, and the through hole 13 for the piezoelectric body are formed. 2 is bonded by a method such as a heat fusion method or an electrostatic bonding method via a low-melting glass, and then the nozzle portion 4 is cut so that the nozzle length becomes 30 to 200 μm.

Thereafter, the comb-shaped PZT piezoelectric body 3 was inserted into the piezoelectric through hole 13 in FIG. 2 (i) to obtain the ink jet printer head shown in FIG.

Embodiment 2 A second embodiment in which the present invention is applied to a diaphragm type ink jet printer head will be described. FIG. 3 is a structural view showing an ink jet printer head according to a second embodiment of the present invention, wherein FIG. 3 (a) is a plan view and FIG. 3 (b).
Is a sectional view taken along the line AA ', FIG. 4C is a sectional view taken along the line BB', and FIG. 4D is a sectional view taken along the line CC '.

As shown in FIG. 3B, in this embodiment, the pressure chamber 34 is etched deeper than in the first embodiment to form a very thin silicon diaphragm 39, on which a piezoelectric body 40 is bonded.

Hereinafter, a method for manufacturing the ink jet printer head according to the second embodiment of the present invention will be described with reference to FIGS. 4 (a) to 4 (g). First, in FIG. 4 (a), a first grooved portion of the nozzle portion 33 is formed by the method described in the first embodiment.
The silicon substrate 31 was manufactured. In the figure, reference numeral 38 denotes a thermal oxide film.

Next, grooves of the diaphragm portion 39, the pressure chamber 34, and the ink chamber 35 were formed on the second substrate 32 by the following method.

First, in FIG. 4 (b), the second (110) crystal plane
A thermal oxide film 36 is formed on both surfaces of a silicon substrate 32, and a photoresist 37 is used thereon to form a pressure chamber 34 and an ink chamber.
In FIG. 4C, a pattern of the thermal oxide film 36 is formed in a pattern of the pressure chamber 34 and the ink chamber 35 by etching with a hydrofluoric acid buffer solution of HF: NH ₄ F = 1: 6.
Was removed. Next, in FIG. 4 (d), 25 wt% KOH
By performing etching with the solution, grooves of the pressure chamber 34 and the ink chamber 35 are formed, and the thickness of the diaphragm 39 is reduced by 40.
It was formed to a thickness of μm. Thereafter, in FIG. 4E, after the thermal oxide film 36 was once removed with hydrofluoric acid, a thermal oxide film 38 was formed again as a protective film.

Next, in FIG. 4 (f), the first substrate 31 on which the nozzle portion 33 is formed as described above, and the second substrate 32 on which the grooves of the pressure chamber 34 and the ink chamber 35 and the diaphragm 39 are formed, After joining, the nozzle part is cut so that the length of the nozzle part becomes 30 to 200 μm. For the bonding, thermal fusion via low-melting glass, an electrostatic bonding method, or the like is used.

Thereafter, the piezoelectric body 40 was bonded onto the diaphragm 39 to obtain the diaphragm type ink jet printer head shown in FIG.

According to this embodiment, even in the long-time etching for forming the diaphragm on the substrate as described above, since the nozzle portion is formed on the other substrate, all the inks are provided on one substrate as in the related art. It is possible to prevent over-etching of the nozzle portion, which has occurred when forming the flow path portion.

Third Embodiment FIG. 5 is a structural view showing an ink jet printer head according to a third embodiment of the present invention. FIG. 2A is a plan view,
FIG. 3B is a sectional view taken along line AA ′, and FIG. 3C is a sectional view taken along line BB ′.
FIG. 4D is a cross-sectional view taken along line CC ′ of FIG. In FIG. 5, 51 is the first having a (100) crystal plane.
A silicon substrate, 52 is a second silicon substrate, 53 is a nozzle portion, 54 is an ink filter, 55 is a pressure chamber, 56 is an ink chamber,
57 is a through hole for a piezoelectric body, and 58 is a piezoelectric body.

As shown in the drawing, this embodiment has a structure in which an ink filter 54 is formed in addition to the nozzle portion 53 on the first substrate of the first embodiment. According to this embodiment, by forming the ink filter 54, clogging of the ink during printing can be effectively prevented.

Hereinafter, a method of manufacturing the ink jet printer head according to the present embodiment will be described.

The method described in the first embodiment is the same as the method described in the first embodiment except that the groove of the ink filter 54 shown in FIGS. 5B and 5C is formed in the same manner as the groove of the nozzle part 53 at the same time when the nozzle part 53 is formed. In the same manner, the first substrate 51 on which the grooves of the ink filter 54 and the nozzle 53 are formed is manufactured.

Since the shape of the ink filter 54 is substantially the same as that of the nozzle portion 53, it is efficient to form the ink filter 54 on the first substrate simultaneously with the nozzle groove. In this case, the etching depths of the ink filter 54 and the nozzle portion 53 are almost the same, and
53 dimensional accuracy is maintained.

Next, similarly to the method described in the first embodiment, a second substrate 52 in which the grooves of the pressure chamber 55 and the ink chamber 56 and the through hole 57 for the piezoelectric body are formed is manufactured.

After joining the first substrate 51 and the second substrate 52 by heat fusion via low-melting glass, electrostatic joining, or the like, the nozzle portion 53 is adjusted so that the length of the nozzle is 30 to 200 μm. Disconnect.

Then, as in the first embodiment, in FIG. 5B, a comb-shaped PZT piezoelectric body 58 is inserted into the through hole 57 for the piezoelectric body,
The ink jet printer head shown in the figure was obtained.

Since the silicon surface repels the ink, a thermal oxide film was formed on the silicon surface in any of the embodiments of the present invention in order to improve ink leakage.

<Effects of the Invention> According to the present invention, the first silicon substrate having the nozzle grooves formed therein and the second silicon substrate having the pressure chamber and ink chamber grooves formed therein have high dimensional accuracy. Since the nozzle portion can be formed, an ink jet printer head having a uniform print dot diameter can be obtained. Further, when the manufacturing method of the present invention is used, the pressure chamber and the ink chamber having a groove deeper than the nozzle portion can be integrally formed, so that a high-performance inkjet printer head can be manufactured with high productivity and at low cost. .

[Brief description of the drawings]

1A to 1D are structural views of an ink jet printer head according to a first embodiment of the present invention, FIGS. 2A to 2J are manufacturing process diagrams of the first embodiment, and FIGS. 4A to 4D are structural views of an ink jet printer head according to a second embodiment of the present invention, and FIGS. 4A to 4G are diagrams illustrating the manufacture of the ink jet printer head according to the second embodiment of the present invention. FIGS. 5 (a) to 5 (d) are structural views of a third embodiment of the present invention, and FIG. 6 is a relation between the azimuth angle of the crystal of the silicon substrate, the deviation angle from the mask pattern, and the nozzle width. FIG. 7 is a structural view of a conventional ink jet printer head. DESCRIPTION OF SYMBOLS 1 ... 1st silicon substrate 2 ... 2nd silicon substrate 3 ... Piezoelectric body 4 ... Nozzle part 5 ... Pressure chamber 6 ... Ink chamber 10 ... Thermal oxide film 13 ... Through-hole for piezoelectric body

Claims (4)

(57) [Claims] 1. An ink jet printer head for forming an ink flow path by forming a groove in a silicon substrate, wherein a first silicon substrate having a nozzle groove formed therein and an ink flow path groove formed behind the nozzle groove. And a substrate surface of the first silicon substrate and a substrate surface of the second silicon substrate are overlapped such that the nozzle groove and the ink flow channel groove are continuous. An ink-jet printer head, characterized in that: 2. The ink jet printer head according to claim 1, wherein a nozzle groove and an ink filter groove having a depth substantially equal to the nozzle groove are formed in the first silicon substrate. 3. The method according to claim 1, wherein a silicon substrate having a (110) crystal plane is used as a second silicon substrate, and the second silicon substrate is deeply etched to form a diaphragm serving as a pressure chamber and a diaphragm. The ink-jet printer head according to claim 1. 4. A step of using a silicon substrate having a (100) crystal plane as a first silicon substrate, forming a V-shaped nozzle groove in the first silicon substrate, and forming an ink flow path in a second silicon substrate. A method for manufacturing an ink jet printer head, comprising the steps of: forming a groove for use;