JPH11157071A - Inkjet head - Google Patents

Abstract

(57) Abstract: A silicon member 9 having a plurality of ink chambers 1;
A plate-like body laminated so as to cover the ink chamber 1;
An ink jet head having a nozzle hole 2 communicating with the ink chamber 1 and a means for applying pressure to the ink chamber 1, wherein the ink chamber has a poor adhesion between the silicon member 9 and the plate-like body and an ink chamber at the time of adhesion. (1) To provide an ink jet printer head capable of preventing distortion and deformation and capable of high-resolution printing. A ceramic having a thermal expansion coefficient of 1.0 to 5.0 × 10 ⁻⁶ / ° C. at 40 to 200 ° C.,
It is formed of glass or glass ceramics.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink jet head used for an ink jet printer.

[0002]

2. Description of the Related Art An ink jet printer is a printer in which ink is ejected from a head to perform printing, and has been widely used in recent years because of low noise and high speed printing.

As shown in FIG. 2, a schematic structure of the ink jet head is such that a vibrating plate 4 for applying pressure to each ink chamber 1 is joined to a head substrate 3 having an ink chamber 1 and a nozzle 2 communicating therewith. The pressure in the ink chamber 1 is increased by deforming the plate 4, and ink (not shown) is ejected from the nozzle 2. Each member is made of a metal material, and a plurality of ink chambers 1 are arranged in a line to constitute an ink jet head. As means for deforming the vibration plate 4, a piezoelectric element 5 is bonded to the vibration plate 4, and a voltage is applied to the piezoelectric element 5 to deform the same.

On the other hand, Japanese Patent Application Laid-Open Nos.
Japanese Patent Application Laid-Open No. 218929 discloses that a ceramic mainly containing any one of aluminum oxide, magnesium oxide and zirconium oxide is used as a material of the ink jet head. As shown in FIG. 3, a head substrate 3 made of these ceramics is provided with a vibrating plate 4 made of a ceramic containing zirconium oxide as a main component.
A piezoelectric vibrator in which a piezoelectric element 5 such as ZT is sandwiched between a lower electrode 6 and an upper electrode 7 is joined.

In order to manufacture such an ink jet head made of ceramics, a ceramic green sheet made of ceramics containing any one of aluminum oxide, magnesium oxide and zirconium oxide as a main component is prepared, and an ink chamber 1 is formed. Requires a step of punching out a portion corresponding to the above with a die. However, there is a problem that the pitch between the ink chambers 1 cannot be reduced due to breakage or deformation of the wall portion at the time of punching, and it is not possible to cope with high density.

As a means for solving this problem, it has been proposed to use silicon as the material of the ink jet head (see Japanese Patent Application Laid-Open No. 7-96605). That is,
By masking and etching the silicon member, a very fine ink chamber is processed, and another plate-like body is joined so as to cover the ink chamber to form an ink jet head.

[0007]

However, in the above-described ink jet head using silicon, it is difficult to bond the silicon member having the ink chamber to another plate. That is, the coefficient of thermal expansion of the ceramic or metal forming the plate is 8 to 12 × 10 ⁻⁶ / ° C., while the coefficient of thermal expansion of silicon is 2 to 4 × 10 ⁻⁶ / ° C. When the two were bonded (thermocompression bonding), peeling was likely to occur. In addition, even if the ink chamber can be adhered without peeling, there is a problem that the ink chamber wall is distorted and deformed. As a result, high-resolution printing has been difficult.

Although the formation of the above-mentioned plate-like body from silicon has been studied, there has been an inconvenience that breakage during thermocompression bonding or breakage during handling occurs due to insufficient strength.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a silicon member having a plurality of ink chambers and a plate-like body laminated so as to cover the ink chamber, and having a nozzle hole communicating with the ink chamber. An ink jet head comprising means for applying pressure to the ink chamber, wherein the plate-like body has a coefficient of thermal expansion at 40 to 200 ° C. of 1.0.
It is characterized by being made of ceramics, glass or glass-ceramics of up to 5.0 × 10 ⁻⁶ / ° C.

Further, according to the present invention, the plate-like body may be made of Si
It is characterized by containing at least one of O ₂ , AlN, SiC and Si ₃ N ₄ as a main component.

That is, according to the present invention, by forming an ink chamber in a silicon member, fine processing by etching can be performed. Further, as a plate-like body laminated so as to cover the ink chamber, 1.0 to
By using ceramics, glass or glass ceramics having a thermal expansion coefficient of 5.0 × 10 ⁻⁶ / ° C., the difference in thermal expansion with the silicon member is reduced, and adhesion failure such as peeling and the like and distortion or deformation of the ink chamber upon adhesion are prevented. Thus, an inkjet head capable of high-resolution printing is obtained.

Further, the present invention is characterized in that the plate-like body has a surface roughness (Ra) of 0.1 to 3 μm, thereby improving the bonding strength with a silicon member. is there.

Further, according to the present invention, the plate-like body has a bending strength of 1%.
It is characterized by a pressure of not less than 00 MPa, thereby improving the overall strength of the ink jet head and preventing damage during thermocompression bonding and damage during handling and the like.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

The ink jet head shown in FIG. 1A comprises a silicon member 9 having a plurality of concave portions forming the ink chamber 1 and a nozzle plate 8 as a plate-like body laminated so as to cover the ink chamber 1. You. Then, the nozzle 2 is formed on the nozzle plate 8, and a part of the silicon member 9 is used as a vibrating portion 9a, and the piezoelectric element 5 having the electrodes 7 and 6 is joined on the vibrating portion 9a.

Therefore, if a voltage is applied to the piezoelectric element 5 to deform it, a pressure is applied to the ink chamber 1 and the ink inside can be ejected from the nozzle 2.

Although only one ink chamber 1 is shown in FIG. 1, a plurality of ink chambers 1 are formed in the silicon member 9 in a line. In order to form the ink chamber 1, the silicon member 9 is masked in a shape conforming to the ink chamber 1 and then etched, thereby processing the ink chamber 1 in a very precise and fine pattern. Can be. As a result, the ink chambers 1 can be arranged at a high density, and it is possible to cope with high-density recording.

On the other hand, the nozzle plate 8 laminated on the silicon member 9 has a coefficient of thermal expansion at 40 to 200 ° C. of 1.0.
It is made of ceramics, glass or glass-ceramics of up to 5.0 × 10 ⁻⁶ / ° C. Therefore, at the time of thermocompression bonding with the silicon member 9 or the like, the difference from the thermal expansion coefficient of the silicon member 9 (2 to 4 × 10 ⁻⁶ / ° C.) is small.
The possibility of peeling or the like can be prevented.

The surface roughness of the nozzle substrate 8 is preferably 0.1 to 3 μm in terms of center line average roughness (Ra). This is because if the surface roughness (Ra) is less than 0.1 μm, the adhesive strength with the silicon member 9 is low because the surface is too smooth. On the other hand, if the surface roughness (Ra) is more than 3 μm, sufficient adhesive strength cannot be obtained due to the formation of a cavity in the adhesive surface. That's why. In order to achieve such a surface roughness, the size of the abrasive grains used when the surface of the nozzle substrate 8 is planarized may be adjusted.

The material of the nozzle substrate 8 is SiO.
_2, AlN, SiC, ceramics as a main component at least one of Si ₃ N _4, is to use a glass or glass ceramic preferable. For example, as a ceramic, a raw material containing AlN, SiC, or Si ₃ N ₄ as a main component and containing a known sintering aid is formed into a predetermined shape by a known method such as press molding or sheet molding. Then, aluminum nitride ceramics, silicon carbide ceramics, and silicon nitride ceramics fired under predetermined conditions are used.

As the glass, a glass produced by using a fused silica powder by a rolling method or the like is used.

Further, as the glass ceramics, those produced by known sheet molding and press molding using a mixed powder obtained by mixing the above fused silica powder and crystallized glass are used.

These ceramics, glass and glass ceramics have a three-point bending strength of 10 according to JIS.
The pressure is preferably 0 MPa or more. This is because, since the strength of the silicon member 9 is low, by laminating the nozzle member 8 with a bending strength of 100 MPa or more, the strength of the entire inkjet head can be increased and breakage during handling or the like can be prevented.

The bonding of the silicon member 9 and the nozzle substrate 8 may be performed by applying an adhesive such as an epoxy resin, thermocompression bonding the two, and heating and curing the adhesive.

Further, a known piezoelectric material such as PZT may be used for the piezoelectric element 5, and the electrodes 6 and 7 are formed of Pt or the like.

Next, another embodiment of the present invention will be described.

The ink jet head shown in FIG. 1 (b) has a nozzle 2 formed on a silicon member 9 having an ink chamber 1 and a vibration plate 4 as a plate-like body laminated so as to cover the ink chamber 1. It is. And this diaphragm 4
Has a coefficient of thermal expansion of 1.0-5.
It is formed of ceramics, glass or glass ceramics of 0 × 10 ⁻⁶ / ° C. Specifically, SiO ₂ ,
It is preferable to use one having at least one of AlN, SiC, and Si ₃ N ₄ as a main component and a bending strength of 100 MPa or more, and have a surface roughness (Ra) of 0.1 to 3 μm.

As still another embodiment, as shown in FIG. 1C, an ink chamber 1 penetrating through a silicon member 9 is formed, and the above-described diaphragm 4 and nozzle Both of the substrates 8 can be provided.

As described above, according to the present invention, a portion of the ink chamber 1 that requires fine processing is formed of the silicon member 9 and the plate-like body such as the vibration plate 4 and the nozzle substrate 8 covering the silicon member 9 is formed of 40 to 20.
The coefficient of thermal expansion at 0 ° C. is 1.0 to 5.0 × 10 ⁻⁶ / ° C.
Various structures can be used as long as they are formed of ceramics, glass or glass ceramics, and are formed by laminating both.

Although only one ink chamber 1 is shown in FIG. 1, many similar ink chambers 1 are formed side by side in the ink jet head of the present invention.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS For the ink jet head shown in FIG.
An adhesion test with the silicon member 9 was performed.

The ink chamber 1 of the silicon member 9 has a width of 120 μm.
m, depth 150 μm, and processed by etching.
The nozzle substrate 8 has a thickness of 0.3 mm and a flatness of 1 μm.
The surface roughness (Ra) was adjusted by changing the size of the abrasive grains during plane processing.

An epoxy resin-based adhesive is screen-printed as an adhesive, and the silicon member 9 and the nozzle
After thermocompression bonding at 300 ° C. and a pressure of 300 g / cm ² for 10 minutes, the adhesiveness and the shape of the ink chamber 1 were examined. The results are as shown in Table 1.

The glass ceramics in Table 1 are those having a ratio of amorphous SiO ₂ in the sintered body to a phase precipitated as crystals of 7.5: 2.5.

[0035]

[Table 1]

As shown in Table 1, No. In 5, 10, and 14, peeling occurred after thermocompression bonding and curing. No. 14 was peeling based on a difference in expansion and contraction due to a difference in thermal expansion coefficient from the silicon member 9. No. In No. 5, because the surface roughness (Ra) was too small, less than 1.0 μm, the adhesive strength between the adhesive and the surface of the nozzle substrate 8 could not be obtained.
In No. 10, since the surface roughness (Ra) was too large than 3.0 μm, cavities were observed on the bonding surface, and a sufficient bonding area was not obtained at the bonding boundary.

As for the other ink jet heads, the shape of the ink chamber 1 was observed from above the ink chamber 1 with a metal microscope. In Nos. 1 and 13, the appearance of deformation was observed. This is caused by a difference in expansion and contraction due to a difference in thermal expansion coefficient.

Ink jet heads (Nos. 2 to 4, 6 to 9, 11,
In No. 12), good adhesion was obtained, and the ink chamber 1 could be bonded without deformation. From the above, the thermal expansion coefficient of the nozzle substrate 8 is desirably 1 to 5 × 10 ⁻⁶ / ° C., and in particular, the thermal expansion coefficient of the silicon member 9 is 2 to 4 × 1
The range of 0 ⁻⁶ / ° C. is a preferable range where no distortion remains at the bonding boundary. The surface roughness (Ra) of the nozzle substrate 8 is:
It is desirable to adjust to 0.1 to 3.0 μm.

When the production yield of ink jet heads made of materials having different three-point bending strengths was evaluated, the thickness of the ink jet head was 1 mm or less. In Nos. 1 to 3, breakage during thermocompression bonding or during handling was frequently observed, and the production yield was extremely low at 60%.

On the other hand, no. In the case of samples 4 to 14, damage was hardly observed, and the production yield reached 90%. From this, it can be seen that when the three-point bending strength is 100 MPa or more as the material of the nozzle substrate 8, no breakage is observed during thermocompression bonding or during hand linking, and the production yield can be increased. In consideration of the occurrence of chipping at the edge of the nozzle substrate 8, high hardness and high fracture toughness are also desirable for hardness and fracture toughness.

It should be noted that, other than the materials mentioned in the above embodiment,
As long as it satisfies the characteristics of the present invention, it can be suitably used for other various ceramics, glass, and glass ceramics.

Further, in the above-described embodiment, as shown in FIG. 1A, an example in which the nozzle substrate 8 is used as a plate-like body laminated on the silicon member 9 is shown. The same applies to the inkjet head having the structure shown.

[0043]

As described above, according to the present invention, a silicon member having a plurality of ink chambers and a plate-like body laminated so as to cover the ink chambers have nozzle holes communicating with the ink chambers. An ink jet head comprising means for applying pressure to the ink chamber, wherein the plate-like body has a coefficient of thermal expansion at 40 to 200 ° C. of 1.0 to 1.0.
5.0 × 10 ^-6 / ° C ceramics, glass or glass-ceramics prevents poor adhesion between silicon member and plate-like body and distortion / deformation of ink chamber at the time of adhesion, enabling high-resolution printing It is possible to provide a simple inkjet printer head.

Further, the surface roughness (Ra) of the plate-like body is set at 0.
By setting the thickness to 1 to 3.0 μm, the adhesive strength with the silicon member can be sufficiently maintained, and by setting the three-point bending strength of the plate-like body to 100 MPa or more, damage at the time of thermocompression bonding and handling during handling can be prevented. Can maintain the strength that can withstand the damage of
An inkjet head with a high production yield can be provided.

[Brief description of the drawings]

FIGS. 1A to 1C are cross-sectional views showing an embodiment of an ink jet head of the present invention.

FIG. 2 is a perspective view showing a conventional inkjet head.

FIG. 3 is a cross-sectional view illustrating a conventional inkjet head.

[Description of sign]

 1: Ink chamber 2: Nozzle 3: Head substrate 4: Vibration plate 5: Piezoelectric element 6: Electrode 7: Electrode 8: Nozzle plate 9: Silicon member

Claims (4)

[Claims] A silicon member having a plurality of ink chambers;
An ink jet head comprising a plate-like body laminated so as to cover the ink chamber, having a nozzle hole communicating with the ink chamber, and having means for applying pressure to the ink chamber, wherein the plate-like body is An ink-jet head comprising a ceramic, glass or glass-ceramic having a thermal expansion coefficient of 1.0 to 5.0 × 10 ⁻⁶ / ° C. at 40 to 200 ° C. 2. The method according to claim 1, wherein the plate is made of SiO ₂ , AlN, Si.
2. The ink jet head according to claim 1, wherein at least one of C and Si ₃ N ₄ is a main component. 3. The plate-like body has a surface roughness (Ra) of 0.1 to 0.1.
2. The ink jet head according to claim 1, wherein the thickness is 3 [mu] m. 4. The ink jet head according to claim 1, wherein the plate-like body has a bending strength of 100 MPa or more.