JPH06218972A - Thermal head - Google Patents

Abstract

(57) [Abstract] [Purpose] Heat resistance of a thermal head in which at least a heating resistor layer, an electrode layer and a protective layer are sequentially laminated on a substrate,
Improves adhesion, corrosion resistance, heat generation performance, reliability and productivity. [Structure] The heating resistor layer 13 is formed of a material containing an oxide, and the element symbols Ti, Zr, Hf, V, Nb, Ta,
The electrode layer 14 is formed of a material containing at least one of metals represented by Cr, Mo, and W as a main component and containing nitrogen, and the heat resistance of the electrode layer 14 and the heat resistance and adhesion to the heating resistor layer 13 are A thermal head that improves both corrosion resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head used in a thermal printer or the like.

[0002]

2. Description of the Related Art In general, the thermal printing recording apparatus is of a type that uses thermal paper, one that thermally transfers ink to plain paper using an ink ribbon, one that uses sublimation dyes to record with ink vapor, etc. There are various types. In such a thermal printing recording device, high speed,
Colorization, multiple recording, gradation recording, etc. are in progress.

In order to achieve such high functionality,
Higher performance of the thermal head is required. First, in order to increase the speed of the thermal head, it is necessary to shorten the energization time to the heating resistor of the thermal head and further increase the applied power to improve the heating temperature of the heating resistor layer. Therefore, as a thermal head that responds to such demands,
The heating resistor layer is made of Ta-SiO ₂ system and the electrode layer is made of Cr / P.
In Japanese Patent Publication No. 56-37071, the heating resistor layer is made of Zr—Al ₂ O ₃ system and the electrode layer is made of C / b.
Japanese Patent Publication No. 63-7442 discloses that r / Au / Cr is used, and Japanese Patent Publication No. 1-47871 discloses that the heating resistor layer is made of Cr-CrO-Si-SiO system and the electrode layer is made of C / Al.
JP-A-60-157884 in which the heating resistor layer is ruthenium oxide and the electrode layer is Ti / Au.
JP-A-2-177502 discloses that the heating resistor layer is ruthenium oxide and the electrode layer is Au.

In order to achieve a long life of the thermal head, it is necessary to prevent corrosion of the thermal head. Therefore, as a thermal head which meets such a demand, a heating resistor is made of Ta ₂ N and an electrode layer is made of Al /
It is proposed in JP-A-62-97391 to use Mo, and in JP-A-62-158063 to use a heating resistor of Ta ₂ N system and an electrode layer of Al / Ni.

As another conventional example, a thermal head disclosed in Japanese Patent Laid-Open No. 01-72862 filed by the present applicant is shown in FIG. In A, a glass glaze layer 2 and a heating resistor layer 3 such as ruthenium oxide (RuO ₂ ) are uniformly laminated on the surface of an alumina substrate 1, and an Al / Si layer is formed on the heating resistor layer 3. Electrode layers 6 having a double structure of 4 and Al layer 5 are formed. Then, the electrode layer 6 and the heating resistor layer 3 are patterned into a predetermined cross-sectional shape as shown in FIG. 4, so that the heating resistor layer 3 in a portion located between both electrodes of the paired electrode layers 6 generates heat. On the heating resistor layer 3 and the electrode layer 6 which are to be elements and are patterned in this way, the Al ₂ O ₃ protective layer 7 and the Si layer are formed.
The composite protective layer 9 including the C protective layer 8 is uniformly laminated.

[0006]

In the thermal head having the structure as shown in FIG. 4 described above, the heating resistor layer 3 in the portion located between both electrodes of the paired electrode layers 6 can locally generate heat. Therefore, it is possible to print an image on a thermal paper or the like by controlling the heating operation. Here, for the electrode layer 6 of the thermal head as described above, conditions such as sufficiently low electric resistivity, adhesion to the heating resistor layer 3 and the like, heat resistance and corrosion resistance are required, Further, in order to realize high-speed image printing and high resolution of the thermal printer, it is necessary to raise the heat generation temperature of the thermal head. Therefore, the surface temperature of the thermal head is currently 35.
It is required to be 0 to 450 (° C). Here, for example, as the material having a low electric resistivity, copper and gold are used in addition to the above-mentioned aluminum, but these copper and gold do not have good adhesion to the heating resistor layer 3 and the like. Copper is not preferable because it does not have sufficient corrosion resistance.

In this respect, aluminum and aluminum alloys shown in FIG. 4 have good adhesion to the heating resistor layer 3 and the like and enable bonding, so that productivity is good. However, unstable contact resistance occurs at the joint, and aluminum has a low melting point and a recrystallization temperature of 200.
The heat resistance is not sufficient because it is as low as around (° C). Also, aluminum is a chemically very active metal as shown in the electrochemical ionization series, and when left in dry air, aluminum oxide (Al ₂ O ₃ ) is produced, which acts as a protective film and causes passivation. The reaction does not proceed any further, but if water is present, aluminum hydroxide Al (OH) ₃
You can And this aluminum hydroxide Al (OH)
₃ is amphoteric and has the property of dissolving in both acid and alkali. Therefore, it is very susceptible to water containing impurities. Further, as the impurity ions, Cl ⁻ , Na ^{+ and the} like are considered, and Cl ⁻ ions and Na ⁺ ions are present everywhere including the human body and thermal paper. When these ions are present and the Al wiring is exposed, Al corrosion is likely to occur in pinholes, cracks, etc. of the protective layer. Therefore, it is not practical to form the electrode layer 6 with aluminum or an aluminum alloy.

Further, if the heat resistance of the electrode layer 6 is not sufficient as described above, the base material for forming the protective layer 7 thereon, that is, the alumina substrate on which the heating resistor layer 3, the electrode layer 6 and the like are formed. Since it is also necessary to keep the temperature of 1 low, this is not preferable because conditions such as the method of forming the protective layer 7 are limited. In the thermal heads disclosed in the above publications, the heating resistor layer is made of a material that raises the heating temperature, but the electrode layers are made of Au, Cr, Al, etc., so that the heat resistance, adhesion, etc. I have a problem.

The present invention solves the problems by selecting the material used for the above-mentioned electrode layer, improves the heat resistance, adhesiveness and corrosion resistance, and has high performance and high reliability and productivity. The head is provided.

[0010]

In a thermal head in which at least a heating resistor layer, an electrode layer, and a protective layer are sequentially laminated on a substrate, the heating resistor layer is formed of a material containing an oxide, and At least a portion of the electrode layer joined to the heating resistor layer is represented by the element symbols Ti, Zr, Hf, V,
It is formed of a material containing at least one of metals represented by Nb, Ta, Cr, Mo and W as a main component and containing nitrogen, and at least a portion of the electrode layer joined to the protective layer is represented by element symbols Ti and Zr. , Hf and at least one of the metals represented by Hf as a main component and formed of a material containing nitrogen.

[0011]

Since the heat resistance of the electrode layer and the adhesion to the heating resistor layer can both be improved, it is possible to improve the heat generation temperature of the thermal head and contribute to speeding up of image printing and resolution. In addition, it is possible to contribute to improving the productivity of the thermal head by raising the temperature of the base material when forming the protective layer, and also to improve the productivity of the thermal head. Since it is possible to prevent corrosion, it is possible to obtain a thermal head having high performance and good reliability and productivity.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. First, as shown in FIG. 1, the thermal head 10 has a glaze layer 12 uniformly formed on a ceramic substrate 11 made of alumina or the like, and a heating resistor containing an oxide such as ruthenium oxide is formed on the glaze layer 12. The body layer 13 is laminated. The electrode layer 14 laminated on the heating resistor layer 13 includes a first electrode layer 15 made of a material containing nitrogen as a main component of so-called refractory metal such as niobium and a second electrode layer made of aluminum. The electrode layer 16 and the electrode layer 16 are laminated to form a two-layer structure. The protective layer 17 formed on the electrode layer 16 is also a first protective layer 18 made of Si—O—N or the like.
And a second protective layer 19 made of SiC or the like are laminated to form a two-layer structure.

In this thermal head 10, since the heating element 20 can be formed by the heating resistor layer 13 located between both electrodes of the electrode layers 14, 14 patterned in a predetermined shape, the heating element 20 is sub-scanned. The serial type and line type thermal heads 10 can be realized by arranging the thermal heads 10 in series in the horizontal direction and the main scanning direction.

In such a structure, in the thermal head 10, a voltage applied between both electrodes of the electrode layers 14 and 14 is controlled to heat the desired heating element 20 to generate a dot matrix type image on a thermal paper or the like. It is designed to print.

A specific example of a method of manufacturing such a thermal head 10 will be described below. First, the heating resistor layer 13 of the thermal head 10 includes, for example, a barium oxide ruthenium (BaRuO ₃ ) target, a mixed target of barium ruthenium oxide (BaRuO ₃ ) and barium titanate (BaTiO ₃ ), a titanium oxide and an oxide. A material containing an oxide such as a mixed target of ruthenium, a mixed target of tantalum and silicon oxide, or a mixed target of niobium and silicon oxide is formed by RF (Radio-Frequency) sputtering to a film thickness of 5
It is formed by forming a film in the range of 00 to 3000 (Å).

The first electrode layer 15 located on the heating resistor layer 13 formed as described above is, for example, a niobium target or a mixed target of niobium and titanium (Nb: Ti = 9: 1 (wt). %)) Etc., so-called refractory metal as the main component, total pressure (argon + nitrogen)
Electric power 2 in a mixed gas of 4.0 to 20.0 (mTorr) and nitrogen / total gas (argon + nitrogen) flow rate of 0 to 50 (%)
It is formed by forming a film with a film thickness of 200 to 2000 (Å) by reactive RF sputtering of 00 to 1500 (W).

Then, the second electrode layer 16 located on the first electrode layer 15 formed as described above is formed by sputtering aluminum to a film thickness of 1.0 to 2.0 (μm). And these first and second electrode layers 15,
The electrode layer 14 is formed by patterning 16 into a predetermined shape by photolithography.

The first and second protective layers 18 and 19 located on the heating resistor 13 and the electrode layer 14 formed as described above are made of Si--O--N and SiC by RF sputtering. It is formed by forming a film with a film thickness of 2 (μm), and the substrate temperature at that time is about 150 (° C.). Further, such Si—O—N of the protective layer 17 can be formed by a plasma CVD method (Chemical Vapor Deposition), and SiH ₄ , N is used for forming the protective layer 17 by the plasma CVD method. ₂ O, NH ₃ , and N ₂ gas are used, and the substrate temperature at that time is 300 to 400.
(℃) is required.

Further, as the protective layer 17 as described above,
A mixed film of alumina and silicon oxide (Al
It is also possible to use silicon carbide (SiC) for the second protective layer 19 using ₂ O ₃ .SiO ₂ ). Furthermore, a mixed film of alumina and silicon oxide (Al ₂ O ₃ .SiO ₂ ) is used for the second protective layer 19 using Si-O-N for the first protective layer.
And a protective layer (not shown) having a three-layer structure using silicon carbide (SiC) as the third protective layer is also possible. The thickness of each layer of the protective layer having such a three-layer structure is (Si-ON) / (Al ₂ O ₃ .SiO ₂ ) / (SiC) = 2.0 (μm) / 5000 (Å) / 2.
It is desirable to set it to about 0 (μm). Similarly, a protective layer (not shown) with a four-layer structure is used for (Si-ON) / (SiC) / (Si-ON) / (SiC) = 2.0 (μm) / 5000 (Å) / 50
00 (Å) /2.0 (μm) (Si-ON) / (SiC) / (Al ₂ O ₃ · SiO ₂ ) / (SiC) = 2.0 (μm) / 5000
(Å) / 5000 It is also feasible to form a (Å) /2.0 (μm), the protective layer of the five-layer structure (not shown), (Si-ON) / (Al 2 O 3 · SiO 2 ) / (SiC) / (Al ₂ O ₃・ SiO ₂ ) / (SiC) =
It is also possible to form it as 2.0 (μm) / 5000 (Å) / 5000 (Å) / 5000 (Å) /2.0 (μm).

Therefore, the applicant of the present invention prototypes various thermal heads using the above-described manufacturing method, using aluminum as the material of the second electrode layer and different materials of the first electrode layer and the heating resistor layer, respectively. These trial thermal heads were left at the set temperature for 1 hour, and then the set temperature was increased with time to measure the resistance change rate. Therefore, the results of this experiment will be described below together with various conditions and evaluation criteria.

1. Composition of heating resistor layer Material (α) ... Ba-Ru-O (Film composition ratio, Ba: Ru = 1: 1
) Material (β) ... Ti-Ru-O (film composition ratio, Ti: Ru = 2: 3
) Material (γ) ... Ta-Si-O (target composition ratio, T
a: SiO ₂ = 53: 47 (mol%)) Material (δ) ... Nb-Si-O (target composition ratio, N
b: SiO ₂ = 50: 50 (mol%)) 2. Composition of first electrode layer Material (1) ... None Material (2) ... Al-Si material (3) ... Nb material (4) ... Nb-Ti material (5) ... Nb-N material (6) ... Nb-Ti -N 3. Definition of resistance change rate (difference in resistance before and after heat treatment / resistance before heat treatment) × 10
0 (%) 4. Definition of heat resistant temperature Temperature at which resistance change rate ≥ 5 (%) 5. Evaluation criteria of heat resistant temperature A ... 500 (° C.) or higher B ... 400 to 500 (° C.) C ... 300 to 400 (° C.) D ... 300 (° C.) or lower

[0022]

[Table 1]

As is apparent from Table 1 above, the first electrode layers (5) and (6) formed of a material containing niobium as a main component and containing nitrogen have electric resistances even if heat treatment is performed at high temperature. It was found that the changes were kept small.

Next, in order to investigate the adhesiveness between the heating resistor layer and the first electrode layer, the present applicant applies the above-mentioned material (α) of Ba—Ru—O as the heating resistor layer. IP with a prototype with a different material for the first electrode layer
It was immersed in A (isopropyl alchol) and subjected to an ultrasonic cleaning test for 20 minutes to confirm the presence or absence of peeling of the first electrode layer. Here, the results of this experiment are illustrated in Table 2.

[0025]

[Table 2]

As is clear from Table 2 above, A
The first electrode layers (2), (5), and (6) made of 1-Si, Nb-N, or Nb-Ti-N are adhered to the heating resistor layer (α) made of Ba-Ru-O. Was found to be good. Incidentally, such first electrode layers (2), (5),
When the adhesion between (6) and the other heating resistor layers (β), (γ) and (δ) was similarly tested, it was confirmed that peeling did not occur and adhesion was good in these cases as well. Was done. In other words, by stacking the first electrode layer containing nitrogen mainly containing niobium on the heating resistor layer containing oxide, this first electrode layer has heat resistance and adhesion to the heating resistor layer. Both were found to be good.

Next, the present applicant prototyped a thermal head on which circuit components such as a driver IC were actually mounted, and changed the drive pulse applied to the thermal head to investigate the life of the apparatus. Here, a thermal head (not shown) in which a first electrode layer (2) made of Al-Si is formed on a heating resistor layer made of Ba-Ru-O is used as a conventional example for comparison. An experiment was conducted. Further, in this experiment, the thermal head was driven in the blank printing state without using thermal paper, and the driving pulse had a pulse width of 0.65 (msec) and a pulse period of 2 (msec). Therefore, the contents of a sample of such an experiment are shown below in Table 3 and the results are shown in FIG.

[0028]

[Table 3]

Therefore, as is clear from the graph of FIG. 2, the thermal head of Sample e manufactured as a conventional example has a resistance change rate of about + 6% when the number of applied pulses is "1 × 10 ⁸ ". Although increasing, in the thermal heads of samples a to d manufactured as the present example, the resistance change rate is negative even when the number of applied pulses is "4 × 10 ⁸ ", and even when driven for a long time. It was confirmed that the characteristics were stable.

In order to confirm the superiority of the heating resistor layer made of a material containing an oxide, the present applicant manufactured the heating resistor layer by RF sputtering with a mixed target as exemplified below. When a driving experiment as described above was performed, all of the samples a to d in Table 3 above were
It was confirmed that the resistance change rate was kept negative as in the case of. 1. Calcium oxide ruthenium (CaRuO ₃ ) 2. Strontium ruthenium oxide (SrRuO ₃ ) 3. Silicon oxide-ruthenium oxide 4. Titanium oxide-ruthenium oxide 5. Tungsten oxide-ruthenium oxide 6. Zirconium oxide-ruthenium oxide 7. Chrome-silicon oxide 8. Titanium-silicon oxide 9. Zirconium-aluminum oxide

In order to confirm the superiority of the electrode layer containing niobium as a main component and containing nitrogen, the applicant of the present invention performed electrode formation by reactive RF sputtering with a mixed target as exemplified below in a gas mixture with argon. When the layers were manufactured and the driving experiment as described above was performed, it was confirmed that similar results were obtained. 1. Niobium-Chromium (Nb: Cr = 9: 1)
(Wt%)) 2. Niobium-molybdenum (Nb: Mo = 9: 1)
(Wt%)) 3. Niobium-tantalum (Nb: Ta = 9: 1)
(Wt%)) 4. Niobium-zirconium (Nb: Zr = 9: 1
(Wt%)) 5. Niobium-Vanadium (Nb: V = 9: 1)
(Wt%)) 6. Niobium-Tungsten (Nb: W = 9: 1)
(Wt%) 7. Niobium-hafnium (Nb: Hf = 9: 1
(Wt%))

In the above description, niobium (N) is used as the metal that is the main component of the first electrode layer that is joined to the heating resistor.
Although b) has been exemplified, the present invention is not limited to the metals of the above elements, and titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium may be used as the metal serving as the main component of the electrode layer. (V), tantalum (Ta),
One of chromium (Cr), molybdenum (Mo), tungsten (W), or a combination thereof may be used, and similar results can be obtained by incorporating nitrogen in the same process as described above. The applicant has confirmed that it can be obtained. The table of the experimental results is shown below.

[0033]

[Table 4]

[0034]

[Table 5]

[0035]

[Table 6]

[0036]

[Table 7]

[0037]

[Table 8]

[0038]

[Table 9]

Further, the present applicant has made the electrode layer by reactive RF sputtering with a mixed target as exemplified below in a gas mixture with argon using a material containing the metals in the above table as main components and containing nitrogen. When the electrode layer was manufactured and the driving experiment as described above was performed, it was confirmed that similar results were obtained. 1. Titanium-Chromium (Ti: Cr = 9: 1
(Wt%)) 2. Titanium-molybdenum (Ti: Mo = 9: 1
(Wt%)) 3. Titanium-tantalum (Ti: Ta = 9: 1
(Wt%)) 4. Titanium-niobium (Ti: Nb = 9: 1
(Wt%)) 5. Titanium-vanadium (Ti: V = 9: 1)
(Wt%)) 6. Titanium-zirconium (Ti: Zr = 9: 1
(Wt%) 7. Titanium-hafnium (Ti: Hf = 9: 1
(Wt%) 8. Molybdenum-Chromium (Mo: Cr = 9: 1
(Wt%) 9. Molybdenum-niobium (Mo: Nb = 9: 1
(Wt%)) 10. Molybdenum-tantalum (Mo: Ta = 9:
1 (wt%)) 11. Molybdenum-zirconium (Mo: Zr = 9:
1 (wt%)) 12. Molybdenum-Vanadium (Mo: V = 9:
1 (wt%)) 13. Molybdenum-Tungsten (Mo: W = 9:
1 (wt%)) 14. Molybdenum-hafnium (Mo: Hf = 9:
1 (wt%)) The same applies hereinafter.

A second embodiment of the present invention will be described with reference to FIG. The present inventor uses the two types of materials, Ba-Ru-O (sample A) and Ta-Si-O (sample B), as materials for the heating resistor layer by the above-described manufacturing method, and uses these heating resistors. For each of the layers, a thermal head using aluminum as the material of the first electrode layer (Sample 1), aluminum as the material of the first electrode layer, and the second electrode layer containing nitrogen with titanium as the main component. A thermal head (Sample 2) made of a material
Furthermore, the first electrode layer is formed of a material containing titanium as a main component and containing nitrogen, and the second electrode layer is formed of aluminum,
Further, a thermal head (Sample 3) in which the third electrode layer is made of a material containing titanium as a main component and containing nitrogen is manufactured, and the thermal head is kept in contact with a thermal paper containing impurity ions and an atmosphere of high temperature and high humidity is produced. (85 ° C, 85%
The sample was left in RH) and the rate of resistance change was measured. Therefore, the results of this experiment will be described below together with various conditions.

1) Composition of heating resistor layer Sample (A) ... Ba-Ru-O (film composition ratio Ba: Ru =
1: 1) Sample (B) ... Ta-Si-O (target composition ratio Ta: SiO
₂ = 53: 47 (mol%)) 2) Composition of electrode layer Sample (1) ... Al (first electrode layer) Sample (2) ... Al (first electrode layer) / Ti-N (second electrode layer) Sample (3) ... Ti-N (first electrode layer) / Al (second electrode layer) / Ti-N (third electrode layer) 3) Definition of resistance change rate (difference in resistance value before and after leaving test / leave Resistance before test) ×
100 (%) 4) Definition of corrosion resistance time Time when resistance change rate ≥ 5 (%) 5) Evaluation criteria of corrosion resistance time A ... 500 hours or more B ... 300 to 500 hours C ... 100 to 300 hours D ... 100 hours or less 6) ion concentration Cl contained in the thermal paper using ^{_{- ... 1000ppm SO 4 2- ... 60ppm}} Na + ... 500ppm K + ... 100ppm

7) Experimental results

[Table 10]

In this experiment, the resistance value of the electrode portion increases with the progress of corrosion due to ions or the like, so that the resistance change rate increases, but as is clear from the above table, the electrode layer joined to the protective layer. When was formed from a material containing titanium as a main component and containing nitrogen, an increase in resistance value due to corrosion in a short time was no longer observed. Further, in order to confirm the superiority of the electrode layer containing titanium as a main component and containing nitrogen, the present inventor uses reactive RF sputtering with a mixed target as described below in a mixture of argon and nitrogen to form a protective layer. When an electrode layer to be joined with was manufactured and the above-mentioned experiment was conducted, it was confirmed that similar results were obtained. 1. Titanium-Chromium (Ti: Cr = 9: 1
(Wt%)) 2. Titanium-molybdenum (Ti: Mo = 9: 1
(Wt%)) 3. Titanium-tantalum (Ti: Ta = 9: 1
(Wt%)) 4. Titanium-niobium (Ti: Nb = 9: 1
(Wt%)) 5. Titanium-vanadium (Ti: V = 9: 1)
(Wt%)) 6. Titanium-zirconium (Ti: Zr = 9: 1
(Wt%) 7. Titanium-hafnium (Ti: Hf = 9: 1
(Wt%))

As described above, titanium is exemplified as the metal serving as the main component of the electrode layer, but the present invention is not limited to the above, and zirconium or hafnium is used as the main component of the electrode layer. Alternatively, it was confirmed that similar results could be obtained by using a mixture of these metals.

[0045]

As described above, the present invention is a thermal head in which at least a heating resistor layer, an electrode layer, and a protective layer are sequentially laminated on a substrate, and the heating resistor layer is made of a material containing an oxide. The element symbols Ti, Zr, H are formed at least in the portion of the electrode layer that is joined to the heating resistor layer.
A portion formed by a material containing nitrogen as a main component represented by f, V, Nb, Ta, Cr, Mo and W, and joined to the protective layer is represented by element symbols Ti, Zr and Hf. Since the electrode is prevented from being corroded and the heat resistance of the electrode layer and the adhesion to the heat-generating resistor layer are both improved by forming the material containing a metal as a main component and containing nitrogen, the thermal head It is possible to contribute to the speeding up of image printing and the enhancement of resolution by improving the heat generation temperature of the above, and also to improve the productivity of the thermal head by raising the base material temperature when forming the protective layer. You can
The effect is that a thermal head having high performance and good reliability and productivity can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional front view showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a change with time of a resistance change rate.

FIG. 3 is a perspective view showing an embodiment of the present invention.

FIG. 4 is a vertical sectional front view showing a conventional example.

[Explanation of symbols]

 10 Thermal Head 11 Substrate 13 Heating Resistor Layer 14 Electrode Layer 17 Protective Layer

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 25, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (2)

[Claims] 1. In a thermal head in which at least a heating resistor layer, an electrode layer, and a protective layer are sequentially laminated on a substrate, the heating resistor layer is formed of a material containing an oxide, and at least the electrode layer is formed. The portions joined to the heating resistor layer are represented by element symbols Ti, Zr, Hf, V, Nb, Ta,
A thermal head comprising a material containing at least one of metals represented by Cr, Mo and W as a main component and containing nitrogen. 2. In a thermal head in which at least a heating resistor layer, an electrode layer and a protective layer are sequentially laminated on a substrate, the heating resistor layer is formed of a material containing an oxide, and at least the electrode layer is formed. 2. The thermal head according to claim 1, wherein the portion bonded to the protective layer is formed of a material containing at least one of metals represented by element symbols Ti, Zr, and Hf as a main component and containing nitrogen.