JP3285719B2 - Ink jet head and method for manufacturing the head - Google Patents

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 for ejecting a liquid from an orifice to form droplets, and a method of manufacturing the head.

[0002]

2. Description of the Related Art An ink jet recording method disclosed in, for example, Japanese Patent Application Laid-Open No. 54-51837 relates to this type of ink jet recording head in that thermal energy is applied to a liquid to obtain a driving force for discharging a droplet. It has features different from other ink jet recording methods.
That is, in the recording method described above, the liquid subjected to the action of thermal energy is overheated to generate bubbles, and a droplet is formed from the orifice at the tip of the recording head by the acting force based on the bubble generation. Is attached to the recording member to record information.

[0003] A recording head applied to this recording method is an orifice generally provided for discharging liquid, and a portion where heat energy for discharging liquid droplets communicating with the orifice acts on the liquid. A liquid discharge unit having a liquid flow path having a heat acting part as a part thereof, a heat generating resistance layer as a heat converter as a means for generating thermal energy, and an upper protective layer for protecting the same from ink for storing heat. Is provided.

However, it is desirable to efficiently transfer heat to the ink from the standpoint of head design and discharge design, and a film configuration without an upper protective layer is disclosed in Japanese Patent Application Laid-Open No. 55-126.
No. 462. The heating resistance layer used in this film configuration must have excellent ink resistance. That is, it must be excellent in electrochemical properties in a high temperature state and resistant to cavitation generated when bubbles are defoamed.

[0005] The heating resistor layer having such characteristics includes:
There is a material such as Ta-Pt proposed in Japanese Patent Application No. 03-194029. In addition, there are materials such as Al-Ta-Ir proposed in Japanese Patent Application No. 01-46769 and materials such as Ta-Ir proposed in Japanese Patent Application Laid-Open No. 03-256747. Furthermore, materials such as Ta-Ir-Ru proposed in Japanese Patent Application No. 03-194031, and Japanese Patent Application No.
There is a material such as Cr-Ir-Ru proposed in 3-194032.

[0006]

In the above recording method, the heating resistor layer must be driven at a very high temperature at very short intervals in order to foam the ink at short intervals. Very high temperature stability is required.

[0007] Recently, high drive frequency and high print quality stability have been demanded for high performance of ink jet, and therefore, it is necessary to stabilize the ejection speed.
That is, foaming stability is strongly required. It is known that the driving pulse width should be reduced for the foaming stability. Therefore, it is necessary to drive the heating resistor layer with a shorter pulse than in the past. The layers are required to have higher temperature stability and heat stress resistance than before. However, in the conventional heat generating resistance layer, a trouble often occurs that the wire is early disconnected when driven by a short pulse. When analyzing a failure mode of driving having a short pulse width, separation occurred between the heating resistance layer and the lower layer, which sometimes caused a disconnection. The cause is that thermal stress is generated due to the difference in thermal expansion coefficient between the heating resistance layer and the lower layer,
This is considered to cause peeling and breakage.

A Pt group metal, for example, Pt, Ir or Ru has poor adhesion to a lower layer and has a poor adhesion to another metal (for example, Ta).
Etc.), the adhesion is not improved. In addition, when other metals (for example, Ta or the like) are increased, the electrochemical property is increased, and early fracture occurs.

An object of the present invention is to provide an ink jet head having a film configuration which is electrochemically stable and has good adhesion without the above problems, and a method of manufacturing the head.

[0010]

The above object is achieved by the present invention described below. That is, the present invention includes a heat acting portion to form a bubble in the liquid by applying thermal energy to the liquid communicating with an orifice for the liquid discharge, thermal energy
A lower layer for heat accumulation and has a electrothermal transducer for generating the thermal energy is provided to the lower portion layer, and an ink jet recording head having a configuration in which electric thermal converter is in contact with the ink directly, The heat-generating resistor layer forming the electrothermal transducer is made of an alloy of a Pt group metal and another metal, and the material in the film thickness direction is partially non-uniform, and at least the lower layer The present invention discloses an ink-jet head characterized in that the material on the side in contact with a Pt group metal has a lower content than that near the lower layer .

Further, the present invention is characterized in that the heat generating resistance layer forming the electrothermal transducer has a material in the film thickness direction which is partially non-uniform and includes at least a material of a lower layer. Also disclosed is an ink jet recording head that performs the following.

Further, the present invention provides a heat acting section which communicates with an orifice for discharging liquid to apply heat energy to the liquid to form bubbles in the liquid, and to store heat energy.
Of the lower layer has a electrothermal transducer for generating the thermal energy is provided to the lower portion layer, and the ink jet head having a structure in which electric thermal converter is in contact with ink directly
In the manufacturing method , as the heat-generating resistor layer forming the electrothermal transducer , an alloy of a Pt group-based metal and another metal, the material in the film thickness direction is partially non-uniform, and at least the lower layer The material on the contacting side is continuously formed so that the content of the Pt group metal is smaller than that near the lower layer.
It discloses a method of manufacturing an ink jet head characterized by being formed into a film .

Further, the present invention is characterized in that the heating resistance layer forming the electrothermal transducer has a partially non-uniform material in a film thickness direction and at least a material of a lower layer is included. It also discloses a method of manufacturing an ink jet head.

The present invention has been made in order to solve the above problems.
The heating resistance layer forming the electrothermal transducer is a Pt group-based alloy, that is, a Pt-based, Ir-based, or Ru-based alloy, and the material is non-uniform in the film thickness direction, and at least the side in contact with the lower layer is Pt, Ir, or It is characterized in that Ru is configured to be small. More specifically, the content of Pt, Ir, or Ru is reduced at the portion in contact with the lower layer of the heating resistor layer, and the Pt, Ir, or Ru content is increased in the thickness direction of the heating resistor layer.

The present invention is also characterized in that the heating resistor layer forming the electrothermal transducer has a material which is partially non-uniform in the film thickness direction and includes at least the material of the lower layer. However, the material is changed in the thickness direction of the heating resistor layer, and the material of the heating resistor layer is used at the center of the heating resistor layer in the thickness direction.

By using the above-mentioned heating resistor layer, the adhesion between the heating resistor layer and the lower layer is improved, and the peeling between the heating resistor layer and the lower layer is pointed out as a conventional problem. Will not occur. Further, in driving a short pulse, the durability against heat stress is improved as compared with the related art. In addition, Pt, Ir, or Ru increases in areas other than the vicinity of the lower layer, and is electrochemically stabilized.

Accordingly, it is possible to drive the head with good foaming stability, and it is possible to provide a highly reliable head having good ejection performance due to good foaming stability.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings, but the present invention is not limited thereto.

(Examples 1 to 3 and Comparative Examples 1 and 2) FIG.
FIG. 2 is a detailed sectional view of the heat generating portion of the present invention, and FIG. Table 1 shows the film configurations of Examples 1 to 3 and Comparative Examples 1 and 2, and Tables 2 to 4 show the film forming conditions of the heating resistance layers of Examples 1 to 3 and Comparative Examples 1 and 2. First, a thermal storage layer 102 as a lower layer is formed on silicon as a substrate 101 to have a thickness of 1.0 μm of SiO ₂ by thermal oxidation.

Next, as the heating resistance layer 103, the first to third embodiments were used.
Table 3 shows the results obtained by co-sputtering using two targets.
The film is formed under the conditions shown in FIGS. The film thickness of each of Examples 1 to 3 was 0.1 μm. In Comparative Example 1, a film of Ta-Pt is formed to a thickness of 0.1 μm by sputtering. In Comparative Example 2, Pt is formed to a thickness of 0.1 μm by sputtering. The film forming conditions of Comparative Examples 1 and 2 were a target power of 1.0 kW and a sputtering gas pressure of 0.5 Pa. The sheet resistance was 20 Ω / □ in Example 1 and Example 2
Is 15 Ω / □, Example 3 is 20 Ω / □, and Comparative Example 1 is 18
Ω / □, and Comparative Example 2 was 12 Ω / □.

Next, as the electrode layer 104, 0.005
μm and Au are deposited by 0.6 μm evaporation. Then, a circuit pattern as shown in FIG. 1 is formed by the photolithography technique, and a heating portion 201 of 30 μm × 150 μm is formed, thereby completing the heater board. The heater board thus completed was subjected to a thermal stress evaluation test under the following conditions. In addition, evaluation of the ability of heat stress durability was based on a rupture pulse.

Driving frequency: 10 kHz Rectangular pulse width: 1.0 μsec Driving voltage: Foaming voltage × 1.4 The results of thermal stress durability evaluation are shown in Table 5. Comparative Examples 1-2
There Whereas are broken at ¹⁰⁶ units from 10 ^five, Examples 1 to 3 was 10 ^nine both. Therefore, the heat stress durability is improved by three digits as compared with the prior art. Since the conventional heating resistance layer has been developed with a pulse width of 5 to 10 μsec, it cannot be put to practical use under the above-mentioned condition of 1.0 μsec as shown in the test results. However, as shown in the test results, the heat generating resistance layer of the present invention can sufficiently withstand a short pulse drive of 1.0 μsec. Therefore, since short pulse driving is possible, stable driving of foaming can be performed, and a highly reliable head with stable ejection performance can be provided.

In the first to third embodiments, the portion in contact with the lower layer of the heating resistor layer is made of a mixture of Pt and another metal, but may be made of only another metal. In the first to third embodiments, the material of the heat-generating resistance layer is changed stepwise, but may be changed gradually. As a matter of course, any material may be used for the heat-generating resistance layer as long as it is durable.

[0024]

[Table 1] * Ta: Pt = 3: 7

[0025]

[Table 2] (Sputter gas pressure: 0.5 Pa)

[0026]

[Table 3] (Sputter gas pressure: 0.5 Pa)

[0027]

[Table 4] (Sputter gas pressure: 0.5 Pa)

[0028]

[Table 5] (Examples 4-6, Comparative Examples 3-4) Table 6 shows Examples 4-6.
The film configurations of Comparative Examples 3 and 4, and Tables 7 to 9 are Examples 4 to 6,
The film forming conditions of the heating resistance layers of Comparative Examples 3 and 4 are shown. First, a substrate 101 is formed on silicon, and a heat storage layer 10 is formed as a lower layer.
2 is formed by thermal oxidation to form SiO ₂ having a thickness of 1.0 μm.

Next, the heat-generating resistance layer 103 is used in Examples 4 to
Table 6 shows the results obtained by co-sputtering using two targets.
The film is formed under the following conditions: The film thickness of each of Examples 4 to 6 was 0.1 μm. In Comparative Example 3, Ta-Ir is deposited to a thickness of 0.1 μm by sputtering. In Comparative Example 4, Ir was deposited to a thickness of 0.1 μm by sputtering. The film forming conditions of Comparative Examples 3 and 4 are a target power of 1.0 kW and a sputtering gas pressure of 0.5 Pa. The sheet resistance value was 20 Ω / □ in Example 4 and Example 5
Is 15Ω / □, Example 6 is 20Ω / □, Comparative Example 3 is 18Ω / □.
Ω / □, and Comparative Example 4 was 12 Ω / □.

Next, as electrode layer 104, 0.005
μm and Au are deposited by 0.6 μm evaporation. Then, a circuit pattern as shown in FIG. 1 is formed by the photolithography technique, and a heating portion 201 of 30 μm × 150 μm is formed, thereby completing the heater board. The thus completed heater board was subjected to a thermal stress evaluation test under the same conditions as in Examples 1 to 3.

Table 10 shows the results of the thermal stress durability evaluation. Comparative Examples 3 and 4 were broken at 10 ⁵ to 10 ⁶ , while Examples 4 to 6 were 10 ⁹ at all. Therefore, the heat stress durability is improved by three digits as compared with the prior art. Since the conventional heating resistance layer has been developed with a pulse width of 5 to 10 μsec, the above-mentioned condition of 1.0 μsec cannot be put to practical use as shown in the test results. However, as shown in the test results, the heat generating resistance layer of the present invention can sufficiently withstand a short pulse drive of 1.0 μsec. Therefore, since short pulse driving is possible, stable driving of foaming can be performed, and a highly reliable head with stable ejection performance can be provided.

In the fourth to sixth embodiments, the portion in contact with the lower layer of the heat-generating resistor layer is made of a mixture of Ir and another metal. In the fourth to sixth embodiments, the material of the heat generating resistance layer is changed stepwise, but may be changed gradually. As a matter of course, any material may be used for the heat-generating resistance layer as long as it is durable.

[0033]

[Table 6] * Ta: Ir = 1: 1

[0034]

[Table 7] (Sputter gas pressure: 0.5 Pa)

[0035]

[Table 8] (Sputter gas pressure: 0.5 Pa)

[0036]

[Table 9] (Sputter gas pressure: 0.5 Pa)

[0037]

[Table 10] (Examples 7 to 9 and Comparative Examples 5 to 6)
9, the film configurations of Comparative Examples 5 to 6, and Tables 12 to 14 show the film forming conditions of the heating resistance layers of Examples 7 to 9 and Comparative Examples 5 to 6. First, a thermal storage layer 102 as a lower layer was formed on silicon as a substrate 101 by thermal oxidation so that SiO ₂ was 1.0 μm thick.
Form.

Next, the heat-generating resistor layer 103 was used in Examples 7 to
9 shows Table 1 by co-sputtering method using two targets.
The film is formed under the conditions 2 to 14. The film thickness of each of Examples 7 to 9 was 0.1 μm. In Comparative Example 5, Ta-Ru is formed to a thickness of 0.1 μm by sputtering. In Comparative Example 6, Ru is formed to a thickness of 0.1 μm by sputtering. The film forming conditions of Comparative Examples 5 and 6 are a target power of 1.0 kW and a sputtering gas pressure of 0.5 Pa. The sheet resistance was 20 Ω / □ in Example 7, and Example 8
Is 15 Ω / □, Example 9 is 20 Ω / □, Comparative Example 5 is 18
Ω / □, and Comparative Example 6 was 12 Ω / □.

Next, as electrode layer 104, 0.005
μm and Au are deposited by 0.6 μm evaporation. Then, a circuit pattern as shown in FIG. 1 is formed by the photolithography technique, and a heating portion 201 of 30 μm × 150 μm is formed, thereby completing the heater board. The thus completed heater board was subjected to a thermal stress evaluation test under the same conditions as in Examples 1 to 3.

Table 15 shows the results of the heat stress durability evaluation. Comparative Examples 5 and ⁶ were broken at 10 ⁵ to 10 ⁶ , whereas Examples 7 to 9 were 10 ⁹ at all. Therefore, the heat stress durability is improved by three digits as compared with the prior art. Since the conventional heating resistance layer has been developed with a pulse width of 5 to 10 μsec, the above-mentioned condition of 1.0 μsec cannot be put to practical use as shown in the test results. However, as shown in the test results, the heat generating resistance layer of the present invention can sufficiently withstand a short pulse drive of 1.0 μsec. Therefore, since short pulse driving is possible, stable driving of foaming can be performed, and a highly reliable head with stable ejection performance can be provided.

In the seventh to ninth embodiments, the portion in contact with the lower layer of the heating resistor layer is made of a mixture of Ru and another metal, but may be made of only another metal. In the seventh to ninth embodiments, the material of the heat generating resistance layer is changed stepwise, but may be changed gradually. As a matter of course, any material may be used for the heat-generating resistance layer as long as it is durable.

[0042]

[Table 11] * Ta: Ru = 1: 1

[0043]

[Table 12] (Sputter gas pressure: 0.5 Pa)

[0044]

[Table 13] (Sputter gas pressure: 0.5 Pa)

[0045]

[Table 14] (Sputter gas pressure: 0.5 Pa)

[0046]

[Table 15] (Examples 10 to 12 and Comparative Example 7) Table 16 shows Examples 10 to 12.
12, the film configuration of Comparative Example 7, and Tables 17 to 19 show the film forming conditions of the heating resistance layers of Examples 10 to 12 and Comparative Example 7.
First, a heat storage layer 102 as a lower layer is formed of a material shown in Table 16 on silicon as a substrate 101.

In the case of SiO ₂ (Example 10, Comparative Example 7)
Is formed to a thickness of 1.0 μm by thermal oxidation. Also, A
In the case of l ₂ O ₃ (Example 11), a film thickness of 1.
It is formed to 0 μm. In the case of Si ₃ N ₄ (Example 1
2) CV using SiH ₄ and NH ₃ as source gases
Formed to a thickness of 1.0 μm by Method D.

Next, the heat-generating resistor layer 103 is used in the tenth embodiment.
Nos. To 12 are formed under the conditions shown in Tables 17 to 19 by co-sputtering using two targets. Example 10
１２12 were all 0.1 μm. Comparative Example 7 is Ta-Ir
Is formed to a thickness of 0.1 μm by sputtering. The film forming conditions of Comparative Example 7 were as follows: target power: 1.0 kW, sputtering gas pressure: 0.5 P
a. The sheet resistance value was 30 Ω / □ in Example 10,
Example 11 was 25 Ω / □, Example 12 was 22 Ω / □, and Comparative Example 7 was 20 Ω / □.

Next, as electrode layer 104, 0.005
μm and Au are deposited by 0.6 μm evaporation. Then, a circuit pattern as shown in FIG. 1 is formed by the photolithography technique, and a heating portion 201 of 30 μm × 150 μm is formed, thereby completing the heater board. The thus completed heater board was subjected to a thermal stress evaluation test under the same conditions as in Examples 1 to 3.

Table 20 shows the results of the heat stress endurance evaluation. Whereas Comparative Example 7 is broken at 10 ^six, Examples 10-12 are broken at 10 ^nine both. Therefore, the heat stress durability is improved by three digits as compared with the conventional case. Since the conventional heating resistance layer has been developed with a pulse width of 5 to 10 μsec, the above-mentioned condition of 1.0 μsec cannot be put to practical use as shown in the test results. However, as shown in the test results, the heat generating resistance layer of the present invention can sufficiently withstand a short pulse drive of 1.0 μsec. Therefore, since short pulse driving is possible, stable driving of foaming can be performed, and a highly reliable head with stable ejection performance can be provided.

In the tenth to twelfth embodiments, the portion in contact with the lower layer of the heating resistor layer is made of a mixed material of the material of the heating resistor layer and the lower layer. However, only the material of the lower layer may be used. In Examples 10 to 12, the material of the heat-generating resistance layer is changed stepwise, but may be changed gradually. As a matter of course, any material may be used for the heat-generating resistance layer as long as it is durable.

[0052]

[Table 16] * Ta: Ir = 1: 1

[0053]

[Table 17] (Sputter gas pressure: 0.5 Pa)

[0054]

[Table 18] (Sputter gas pressure: 0.5 Pa)

[0055]

[Table 19] (Sputter gas pressure: 0.5 Pa)

[0056]

[Table 20]

[0057]

As described above, according to the present invention, the heating resistance layer forming the electrothermal converter is made of a Pt group alloy, that is, Pt-based alloy.
System, Ir system or Ru system alloy, the material is non-uniform in the film thickness direction, and at least the side in contact with the lower layer is Pt, Ir
Alternatively, the content of the Ru metal is small, and the portion in contact with the lower layer of the heat generating resistance layer is made of Pt, Ir.
Alternatively, the content of the Ru metal is reduced, and the content of the Pt, Ir, or Ru metal is increased in the thickness direction of the heat generating resistance layer.

Further, the material of the heat generating resistance layer forming the electrothermal transducer is partially non-uniform in the film thickness direction, and at least the material of the lower layer is included. The portion in contact with the layer is configured to substantially match the material of the lower layer. Then, the material is changed in the thickness direction of the heating resistor layer, and the material of the heating resistor layer is used at the center in the thickness direction of the heating resistor layer.

By using the heating resistor layer as described above, the adhesion between the heating resistor layer and the lower layer is improved, and peeling between the heating resistor layer and the lower layer as in the conventional problem is prevented. Does not occur. In driving a short pulse, the durability against heat stress was improved as compared with the related art. Further, Pt, Ir, or Ru increased in areas other than the vicinity of the lower layer, and became electrochemically stable.

Therefore, it is possible to drive with good foaming stability, and to provide a highly reliable head with good ejection performance due to good foaming stability, and to provide a high-performance and highly reliable ink jet head. can do.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a heating unit heater board of the present invention.

FIG. 2 is an XY cross-sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Substrate 102 Heat storage layer 103 Heating resistance layer 104 Electrode layer 201 Heating part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/05 B41J 2/16 G01D 15/18

Claims (6)

(57) [Claims] And 1. A heat acting portion communicating with the orifice for a liquid discharge by applying thermal energy to the liquid to form a bubble in the liquid, a lower layer for heat accumulation of the thermal energy, on the lower portion layer provided having an electric-heat converter for generating the thermal energy, in having a structure in which electric thermal converter is in contact with ink directly
In the jet head , the heating resistance layer forming the electrothermal transducer is made of an alloy of a Pt group metal and another metal, the material in the thickness direction is partially non-uniform, and at least the lower layer Yes the content of Pt-group metal of the material of the nearby, what are those smaller than the other near the bottom layer in contact
An ink jet head characterized in that: 2. The Pt group metal is Pt, Ir or Ru.
The ink jet according to claim 1, wherein
Head . 3. The method according to claim 2, wherein the other metal is Ta.
The inkjet head according to claim 1, wherein 4. A heat acting portion communicating with the orifice for a liquid discharge by applying thermal energy to the liquid to form a bubble in the liquid, a lower layer for heat accumulation of the thermal energy, on the lower portion layer provided having an electric-heat converter for generating the thermal energy, in the manufacturing method of the ink-jet head having a structure in which electric thermal converter is in contact with the ink directly, as a heat generating resistive layer for forming the electrothermal transducers A material composed of an alloy of a Pt group metal and another metal, the material in the film thickness direction is partially non-uniform, and the content of the Pt group metal in the material at least near the lower layer is close to the lower layer. Continuously to reduce the number of
A method for manufacturing an ink jet head, comprising forming a film . 5. The Pt group metal is Pt, Ir or Ru.
The method for manufacturing an ink jet head according to claim 4, wherein: 6. The method for manufacturing an ink jet head according to claim 4 , wherein said other metal is Ta .