JPH0825289B2 - Thermal head and manufacturing method thereof - Google Patents

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 heat-generating print recording apparatus such as a facsimile and a printer, and a manufacturing method thereof.

[0002]

2. Description of the Related Art A standard thermal head for facsimile use has a standard resolution of 7.7 dots / mm in the sub-scanning direction. However, with the recent trend toward higher grade facsimiles, there has been a demand for a thermal head in which the resolution in the sub-scanning direction is increased to, for example, 15.4 dots / mm without lowering the heating resistor value.

In order to increase the resolution in the sub-scanning direction, the shape of the heating resistor is first changed. For example,
In order to double the resolution in the sub-scanning direction, the length of the heating resistor in the main scanning direction is not changed, but the length of the heating resistor in the sub-scanning direction is halved. However, with this alone, the resistance value of the heating resistor is also halved, the inflow current is doubled, and it is disadvantageous in terms of the total cost including the power supply and the like. Therefore, it has been attempted to increase the resistance by reducing the thickness of the heating resistor.

However, if the film thickness of the heating resistor is remarkably reduced, the heat resistance and the like are deteriorated, which leads to shortening the life of the thermal head. Therefore, in order to increase the resistance value of the heating resistor without reducing the film thickness, it is necessary to increase the specific resistance value. Specifically, 30m
Ω · cm extent is desired. Here, in order to obtain a high resistivity film, Ta-SiO ₂ material is known to be advantageous. However, it was revealed by the experiments by the present inventors that the stability of the Ta-SiO ₂ film was significantly lost as the resistivity was increased.

For example, general SiO ₂ is 53 mol%
When a heating resistor film is formed using a sputtering target whose remaining balance is substantially Ta, how the film forming conditions such as sputtering output, sputtering gas pressure, and sputtering gas flow rate and the film forming apparatus structure are changed. However, the upper limit of the specific resistance value of the film that can be stably formed is 15 mΩ · cm. Further, it contains 55 mol% of SiO ₂ and the balance is substantially T.
An attempt was made to form a film by using a sputter target consisting of a. Although a specific resistance film of 30 mΩ · cm or more could be obtained, the problem that the variation of the sheet resistance value was extremely deteriorated. . The variation of the resistance value in the head obtained from the formula of [(highest resistance value−minimum resistance value) / average value × 100 (Ω / mouth)] is SiO ₂ 53 mol%
In the case of composition, what was about ± 13% is SiO ₂
In case of 55 mol% composition, as shown in FIG.
%.

Normally, the standard internal resistance value of the thermal head is within ± 10%. With a heating resistor film having a specific resistance value variation of ± 45%, even if correction is made by the film thickness. It is extremely difficult to set it within ± 10%. Even if the correction is possible, the behavior of the change in the resistance value in the head during running of the actual machine remarkably differs depending on the parts, so that the thermal head becomes unreliable. Further, the large variation in the specific resistance value within the head means that it also increases between the individual thermal heads. Recently, the variation in the specific resistance value between thermal heads is required to be within ± 5%, but Ta-containing 55 mol% SiO ₂ composition is used.
In the case of the SiO ₂ film, it exceeds ± 20%, and the production yield is extremely reduced.

Further, the higher resolution of the thermal head causes the following problems. That is, in a high-resolution thermal head, the area of the heating resistor is significantly reduced, so that the energy density during running of the actual machine is inevitably high. Therefore, even if the amount of electric aging after mounting for stabilizing the heating resistor is performed at a level equivalent to that of a thermal head having a normal resolution, a high resolution thermal head cannot provide a sufficient effect. Therefore, the electric aging amount has to be made larger than that of a normal thermal head, but this has a limit. For example, the normal sub-scanning direction resolution is 7.7 dots / mm.
In the thermal head, the thermal head with stable resistance value was obtained by the electric aging of the level that reduces the resistance value by about 6%, but the resolution in the sub-scanning direction was 15.4 dots / mm. At the head
Electrical aging of a level that reduces the resistance value by approximately 12% is required. However, when electric aging of -12% is performed, phenomena such as blistering or corrosion of the conductive film connected to the heating resistor and blistering of the protective film of the heating resistor may occur depending on the head or the head portion. These also lead to abnormal resistance values.

On the other hand, a heat-resistant insulating substrate in which a heat-resistant resin layer such as a polyimide resin is provided as an insulating layer or a heat storage layer on a ceramic substrate or a metal substrate is used as a high resistance substrate of a thermal head. There is. A thermal head using such a heat-resistant insulating substrate has a polyimide resin having a thermal diffusivity of 1/3 to that of a conventional glaze glass layer.
Since it is as low as about 1/6, the thermal efficiency is very excellent. Further, since it becomes possible to use a flexible support substrate such as a metal substrate, it becomes possible to perform bending work. Therefore, it is attracting attention as a small-sized, inexpensive, and high-performance thermal head.However, in such a thermal head, even if the resolution is normal, the resistance value of the heating resistor tends to vary, which causes a problem. ing.

For example, as a thermal head having a heat-resistant resin layer, a heat-resistant resin layer made of a polyimide resin or the like which also serves as a heat storage layer and an insulating layer is formed on a metal substrate made of an Fe alloy or the like, and a silicon oxide is formed on the heat-resistant resin layer. nitride, sputtering ing coercive Mamoruso of amorphous silicon carbide or the like, after forming by plasma CVD method or the like,
That the heating resistor consisting of Ta-SiO ₂ or the like on the coercive Mamoruso This was film formed by a sputtering method, and the like are known. Here, on the coercive Mamoruso such as silicon oxynitride, when the heating resistor film made of Ta-SiO ₂ or the like formed by a sputtering method, the area resistance value would indicate a large variation. According to the experiments conducted by the present inventors, despite optimization of film forming conditions such as sputtering output, sputtering gas pressure, and sputtering gas flow rate, for example, on a substrate having a predetermined area where a thermal head is formed. And the variation reached ± 50%.

As described above, the standard variation of the in-head resistance value of the thermal head is within ± 10%. To this end, considering the variation in the shape at the time of pattern formation, the resistance value at the time of film formation of the resistor is considered. The variation is required to be within ± 6%. In the case of a substrate in which a Grace glass layer was formed on a ceramic plate, it was possible to deal with it relatively easily by providing a film thickness distribution. Even when a heat-resistant insulating substrate having a polyimide resin layer or the like is used, it is possible to make a correction based on the film thickness, but since the variation is large, the control of the film thickness becomes extremely difficult. Further, even if the variation in the sheet resistance value can be reduced from ± 50% to within ± 6% by controlling the film thickness, the variation in the specific resistance value does not change as it is. The non-uniformity of the resistance change during actual machine running becomes extremely remarkable as compared with the case of using a substrate in which a Grace glass layer is formed on a conventional ceramic plate, and the film thickness distribution becomes even more remarkable, Of course, the thinned portion is inferior in heat resistance and is easily broken, so that the life of the element is shortened. Such a thermal head is not very practical. In order to put it into practical use, it is essential to form a heating resistor film having a small variation in area resistance value, that is, a small variation in specific resistance value.

Further, a thermal head using a polyimide resin layer as a heat retaining layer is known to have better printing characteristics such as thermal efficiency than a thermal head formed on an ordinary ceramics substrate. It is desired to increase the resistance value of the heating resistor in order to further utilize it, to reduce the cost of the power supply used for the thermal head and the printing apparatus, and to achieve higher resolution as described above. For such demands, although Ta-SiO ₂ film of SiO ₂ 55 mol% composition as described above is valid, the variation of further specific resistance value in the heating resistor film having the above composition becomes remarkable Will end up.

Further, in the case of a thermal head using a polyimide resin layer as a heat retaining layer, if a normal electric aging process for stabilizing the heating resistor is performed after mounting,
The polyimide resin is often damaged, which is industrially difficult.

[0013]

As described above, in the high resolution thermal head, the heating resistor having a small variation in the specific resistance value when the specific resistance is increased and the polyimide resin layer as the heat insulating layer are used. In the conventional thermal head, there is a strong demand for a heating resistor capable of reducing the variation in the specific resistance value even on the protective layer. Further, in those manufacturing methods, there is a strong demand for making it possible to stabilize the heating resistor without requiring electrical aging after mounting.

The present invention has been made to address such a problem, and it is possible to essentially minimize the variation in the specific resistance value of the heating resistor and to easily stabilize the heating resistor. An object of the present invention is to provide a possible thermal head and a manufacturing method thereof.

[0015]

A first thermal head according to the present invention includes an insulating support base, a large number of heating resistors formed on the insulating support base, and a plurality of heating resistors. In a thermal head having a conductor connected thereto, the heating resistor is made of silicon in an amount of 5 to 25 mo.
1% and oxygen in the range of 10 to 50 mol% , and the balance is substantially formed by a composite body made of Nb or an Nb alloy. The second thermal head in the thermal head having the above structure, and in particular the on the supporting substrate and the heat-resistant resin layer and the coercive Mamoruso using an insulating supporting substrate formed in this order.

Further, according to the method of manufacturing a thermal head of the present invention, a large number of heating resistors are formed on the insulating support base, and a conductor connected to each heating resistor is formed to manufacture the thermal head. To do this, add 15 parts of silicon oxide.
A heating resistor film is formed on the insulative supporting substrate by using a sputtering target that is contained in the range of mol% to 70 mol% and the balance is substantially Nb or Nb alloy. It is characterized in that the heat treatment is performed in the temperature range of ℃ to 900 ℃.

In the thermal head of the present invention, silicon is used in an amount of 5 to 25 mol% and oxygen is used in an amount of 10 to 10 as a heating resistor.
A composite containing 50 mol% and the balance being substantially Nb or Nb alloy is used. Examples of the Nb alloy include Nb-Ta alloy and Nb-Fe alloy. Here, in the case of a heat resistant resin insulating substrate in which a heat resistant resin layer such as a polyimide resin layer is formed on a metal substrate, as described above, compared to a substrate in which a grace glass layer is formed on a normal ceramics substrate, The variation in the sheet resistance value of the heating resistor film increases about three times. Further, even when an attempt is made to increase the specific resistance of the heating resistor, the variation in the sheet resistance value is also greatly increased. As already mentioned, in order to improve the variation in the sheet resistance value, it is necessary to take an essential improvement measure to reduce the variation in the specific resistance value, and for that purpose, the heating resistor with originally small variation in the specific resistance value is required. Materials are required. Note that tantalum nitride, which has been conventionally used as a heating resistor material for a thermal head, has a problem that the specific resistance value is too low. On the other hand, Ta-SiO ₂ is relatively high resistivity has the disadvantage that it is difficult to control the resistance value as described above.

On the other hand, the heating resistor material in the thermal head of the present invention, that is , 5 to 25 mo
A composite containing 1% and oxygen in the range of 10 to 50 mol% and the balance substantially consisting of Nb or Nb alloy truly satisfies the above-mentioned demand. This is because the atomic weight of Ta is 180, whereas that of Nb is as small as 90, which is close to the molecular weight 60 of SiO ₂ . If the mass difference between the metal particles and the SiO ₂ particles is small, the particle emission angle by sputtering becomes similar, and the degree of scattering by the sputter gas such as Ar also becomes close, so that the composition variation on the substrate is reduced. In this way, by making it possible to suppress the variation in composition,
It is possible to obtain a heating resistor film which has an excellent specific resistance distribution and which has essentially a small variation in area resistance value. Further, even when the molar ratio of SiO ₂ is increased, it is possible to similarly suppress the composition variation. Therefore, even when the specific resistance of the heating resistor is increased, it is possible to reduce the variation in the sheet resistance value.

The reason for limiting the molar ratios of silicon and oxygen in the above composite to the ranges of 5 to 25 mol % and 10 to 50 mol % respectively is as follows. When the molar ratios of silicon and oxygen are less than 5 mol% and less than 10 mol%, respectively , the specific resistance becomes too small and the function as a resistor deteriorates. On the other hand, the molar ratios of silicon and oxygen are
If it exceeds 25 mol% or 50 mol% , it becomes difficult to manufacture the target, and it becomes difficult to control the resistance value, so that the variation in the sheet resistance value tends to increase. The molar ratio of silicon and oxygen is 10 to 20 mol % and 20 to 40 m , respectively.
More preferably, it is ol% .

5 to 25 mol% of silicon as described above ,
A heating resistor containing oxygen in the range of 10 to 50 mol% and the balance substantially consisting of a Nb or Nb alloy composite can be obtained by, for example, performing sputtering using the above composite as a target.

The heating resistor film obtained by this sputtering is preferably heat-treated at a temperature range of 200 ° C to 900 ° C. However, the thermal head of the present invention can withstand practical use without such heat treatment, and heat treatment is not an essential condition. However, heat treatment in advance stabilizes the heating resistor more effectively. , The change over time is further reduced. Further, the heating resistor can be stabilized to a level that cannot be achieved by conventional electric aging. As a result, in the conventional thermal head, not only the electrical aging process of the resistor, which is performed after mounting, can be omitted, but also the pulse resistance life is extended. Further, since the heat treatment process is performed in a very initial manufacturing process, the resistance of the heating resistor stabilized at this time is suppressed from varying in resistance value, and the process yield is also improved.

The heat treatment temperature for the heating resistor film is set in the temperature range of 200 ° C. to 900 ° C. as described above. If the heat treatment temperature exceeds 900 ° C., the resistance value of the heating resistor film is likely to be abnormal.
Further, if the temperature is lower than 200 ° C., the effect of heat treatment cannot be sufficiently obtained. More preferable heat treatment temperature is 3
The temperature is in the range of 00 ° C to 800 ° C, more preferably 40
It is in the range of 0 ° C to 750 ° C. Also, this heat treatment is
It is preferably performed in a vacuum of 10 ^-1 Torr or less or in an inert atmosphere such as a nitrogen atmosphere or an argon atmosphere. By performing heat treatment in these atmospheres,
Oxidation of the heating resistor film is suppressed, the area resistance value in the substrate is more easily made uniform, and the controllability is improved. further,
The heat treatment is preferably applied before the conductor is formed. This is because if the heat treatment is performed after the conductor is formed, the conductor material is likely to diffuse into the heating resistor film, which is not preferable in controlling the resistance value.

[0023]

EXAMPLES Examples of the thermal head of the present invention will be described below.

First, a concrete example of the heating resistor according to the present invention and its evaluation result will be described.

A polyimide resin layer and Si-Zr-Y- were arranged in the same vacuum chamber by using a sintered body target containing 55 mol% of SiO ₂ and the balance being substantially Nb.
On a stainless steel substrate and a N-O compounds ing from coercive Mamoruso, and the heating resistor film is formed by RF sputtering. This substrate is about 1 mm thick and 55 mm x
It has a film forming area of 270 mm. The sputtering conditions are high-frequency power of 2.0 kw and Ar pressure of 15 mTorr.
r, Ar flow rate 50 SCCM, Nb film thickness 100 nm
It was obtained -SiO ₂ film. The film forming apparatus used has a mechanism for forming a film by allowing the substrate to pass in parallel to a fixed target surface. The substrate passing speed was not intentionally changed so as to have a film thickness distribution that improves it, and the speed was set to a constant speed.

Nb-Si produced under such film forming conditions
When the sheet resistance value of the O ₂ film in the substrate was measured, it was 3.3 k.
An average value of Ω ± 5.5% and variation were shown. Regarding the specific resistance value, the average value of 33 mΩ · cm ± 5.8% and the variation were shown. Here, the area resistance value in the substrate was measured at 20 points evenly in the longitudinal direction in the central portion of the substrate, and the variation was [(maximum resistance value−minimum resistance value) / average value × 100 (Ω /
Mouth]]. The specific resistance is 20
It is calculated from the product of the film thickness at the point and the resistance value of the curved product.

On the other hand, as a comparison with the present invention, except that a sintering target containing 55 mol% of silicon oxide and the balance being substantially Ta is used, the same substrate and Ta-SiO ₂ are used under the same conditions and conditions as in the above-mentioned embodiment. When a film was prepared, the area resistance value and the specific resistance value were 3.4 kΩ ± 44.5%,
It was 34 mΩ · cm ± 50.3%.

Thus, the Nb-SiO ₂ according to the present invention is
It can be understood that the resistance film has a markedly excellent variation in the sheet resistance value as compared with the conventional Ta-SiO ₂ resistance film, and that this is a reflection of the small variation in the specific resistance value.

Next, a thermal head as shown in FIG. 1 was manufactured using the above-mentioned two types of resistor films. FIG. 1 is a cross-sectional view of essential parts schematically showing the configuration of a thermal head according to an embodiment of the present invention. A polyimide resin layer is provided as the heat-resistant resin layer 2 on the support substrate 1 made of an Fe-Cr alloy, and S is formed on the heat-resistant resin layer 2.
i-Zr-Y-N- O compound ing from product coercive Mamoruso 3 is provided. Further, on the coercive Mamoruso 3 This heating resistor 4 using two kinds of resistor film mentioned above individually are formed by sputtering. Then, a conductive layer 6 made of Al, that is, an individual electrode and a common electrode are formed on the heat generating resistor 4 so as to form an opening which becomes the heat generating part 5, and Si- is formed so as to cover at least the heat generating part 5.
A protective layer 7 made of a Zr—Y—N—O compound is formed. A large number of heating resistors 4 were provided by patterning, and a thermal head having a resolution of 8 dots / mm in the main scanning direction and a resolution of 15.4 dots / mm in the sub scanning direction was manufactured.

When the in-head resistance value distributions of these two types of thermal heads were examined, it was found that a thermal head using a conventional Ta-SiO ₂ resistor film had a resistance of 2.
The thermal head using the Nb-SiO ₂ resistor film of the present invention is 2.8 kΩ ± 6.5% as shown in FIG.
%, Which was a practical level. As described above, the thermal head using Nb-SiO ₂ of the present invention for the heating resistor has a markedly improved variation in resistance value as compared with the conventional thermal head, and in particular, the polyimide resin layer is provided as the heat retaining layer. , Greatly contributes to the practical application of a highly efficient thermal head.

In addition, 50 substrates having Nb-SiO ₂ resistor films formed thereon were prepared under the above conditions, and ₂ of these substrates were prepared.
For 5 sheets, 45 in a vacuum of 2 × 10 ⁻⁵ Torr.
Heat treatment was performed at a temperature of 0 ° C. By this heat treatment, the sheet resistance value was reduced by 10% to 3.0 kΩ. Also,
The variation was ± 5.5%, which was unchanged. Then, the thermal heads having the above-described configurations were produced together with the 25 substrates that were not subjected to the heat treatment. Since four thermal heads can be taken from one substrate, 100 thermal heads each with or without heat treatment were obtained. Incidentally, in a normal thermal head, electric aging is performed for the purpose of stabilizing the resistance value before running the actual machine, but here, only 100 thermal heads not subjected to the heat treatment are Electric aging was performed until the resistance value decreased by 10%.

The yield until the completion of the thermal head by the above steps was obtained. As for the specifications of the thermal head, the variation in resistance within the head is within 2.8 kΩ ± 10%, and the variation in resistance between heads is within 2.8 kΩ ± 10%.
As a result, the yield of the heat-treated product was 98%. This is because the film quality is stabilized by the heat treatment, and the variation in the resistance value during the process is much smaller than that of the product not subjected to the heat treatment.

As described above, in the thermal head using the heat-resistant resistor film of the present invention, the process yield is significantly improved as compared with the thermal head using the heat-resistant resistor film. In this example, the vacuum heat treatment apparatus was used for heat treatment, but this may be any method that applies heat to the resistor film, for example, electric field application, laser irradiation, etc., and is not limited to the above method. Not a thing.

Further, a pulse resistance life test was conducted on two types of thermal heads produced by the above steps, with and without heat treatment. The test condition is a pulse width of 0.8 mse
c, with a repetition cycle of 2 msec, a pulse of energy of 0.16 mJ / dot was continuously applied to the heating resistor, and the change in resistance value of the heating resistor was measured. The results of these tests are shown in FIG. In FIG. 4, A is a thermal head with heat treatment and no electric aging, and B is a thermal head without heat treatment and with electric aging. The thermal head of B also showed excellent life characteristics such as a resistance change rate of -4.0% when the number of pulses applied was 10 ⁸ , but
The thermal head of -1.1% shows even more excellent characteristics. This also shows that the conventional electric aging step can be omitted by introducing the heat treatment process. Further, the rise in heat generation temperature due to the decrease in the resistance value is suppressed, so that the heat damage to the polyimide resin layer is reduced. Therefore, according to an additional experiment, regarding the thickness of the polyimide protective layer, the thermal head without heat treatment needs to be at least 1 μm to sufficiently withstand practical use, while the thermal head with heat treatment has a thickness of 0.3 μm. It became enough.

As described above, the thermal head having the resistor film subjected to the heat treatment of the present invention has a significantly improved process yield as compared with the conventional thermal head, and the conventional electric aging process can be omitted. The polyimide protective layer can be made very thin, which greatly contributes to cost reduction.

Next, another embodiment of the present invention will be described. Containing 55 mol% of SiO ₂ , the balance being substantially Nb
A ceramic substrate having a glaze glass layer as an insulative support substrate was placed in the same vacuum chamber using the sintered target made of, and a resistor film was formed on the substrate by a high frequency sputtering method. The sputtering conditions were a high frequency power of 2.0 kW, an Ar pressure of 15 mTorr, an Ar flow rate of 150 SCCM, and a film thickness of 110 nm of Nb-SiO.
_Two films were obtained. When the in-substrate area resistance value of this Nb-SiO ₂ film was measured, it showed an average value of 3.71 kΩ ± 2.2% and a variation. The specific resistance value is 40.8
An average value of 1 Ω · cm ± 2.3% and variation were shown.

When another Nb-SiO ₂ film was formed on 99 other substrates under the same sputtering conditions, the average sheet resistance value of each substrate was 3.63 kΩ to 3.77 kΩ, and the average specific resistance value was 39.8 mΩ. cm to 41.5 mΩ · cm, which was extremely reproducible. Further, in each of the substrates, the variation in the average sheet resistance value and the average specific resistance value was ± 4% or less.

Further, the substrate 100 thus obtained
The sheet was heat treated at a temperature of 500 ° C. Heat treatment is 3 ×
It was performed by heating with an infrared heater in a vacuum of 10 ⁻⁵ Torr or less. By this heat treatment, the sheet resistance value of 100 substrates uniformly decreased by 12%. It should be noted that the variation in the resistance value within the substrate of each substrate was not changed and was 4% or less.

Next, a thermal head having a resolution in the main scanning direction of 8 dots / mm and a resolution in the sub-scanning direction of 15.4 dots / mm is formed using the substrate having the resistor film (ceramic substrate having the glaze glass layer). Was produced. The heating resistor was patterned into a rectangle of 110 μm in the main scanning direction and 90 μm in the sub scanning direction. The sub-scanning direction of 90 μm means that the resolution in the normal sub-scanning direction is 7.
It is half the size of a thermal head of 7 dots / mm. The configuration was the same as that of the above-described embodiment shown in FIG. 1 except for the shapes of the insulating support substrate and the heating resistor.

In this way, a total of 400 thermal heads were manufactured. FIG. 5 shows variations in the specific resistance value of a typical thermal head. In the case of this thermal head, the average value is 35.8 mΩ · cm, and the variation is ± 2.6.
%Met. The resistance value of the thermal head with a resolution of 15.4 lines / mm in the sub-scanning direction is ± 1 within the head.
0% or less, usually 2.66 kΩ to 2.94 k between heads
Although about Ω is required, all of the 400 thermal heads obtained in this example satisfy the above-mentioned standard.

[0041] In _contrast, using a Ta-SiO ₂ film of SiO 2 55 mol% composition, similarly were manufactured thermal head, the yield by standard that the 7% to 8
It was about%. Further, when a thermal head was manufactured by using the Nb-SiO ₂ film to stabilize the heating resistor by electric aging after mounting, the yield was 47%. From this, it can be seen that the heat treatment is directly applied to the heating resistor film.

Further, in FIG. 6, a heating resistor film made of Nb-SiO ₂ is heat-treated at 500 ° C. (C-1) and 600 ° C. (C-2) in a vacuum of 3 × 10 ⁻⁵ Torr or less. ), A thermal head subjected to heat treatment (C-3) at 400 ° C., and after mounting, -8% electric aging (D-1) and -12% electric aging (D-).
2 shows the pulse life resistance characteristics of the thermal heads subjected to 2). The substrate and other conditions for forming the heating resistor were the same as those in the above-mentioned embodiment. The test condition is 1
A pulse width of 0.75 according to the typical high resolution thermal head of 5.4 dots / mm thermal head.
The change in resistance value of the heating resistor was measured by continuously applying a pulse of energy of 0.16 mJ / dot to the heating resistor at msec and a repeating cycle of 2 msec. Normally, the standard is that the rate of change in resistance value is within ± 10% when a pulse is applied 1 × 10 ⁸ times.

As is apparent from FIG. 6, the 400 ° C. heat-treated product (C-3) and the -8% electric aging (D-1) show almost the same behavior, and therefore both of them have the same heating resistance. It has a stabilizing effect, and both can be said to have a slight lack of stabilization. The 500 ° C. heat-treated product (C-1) and the −12% electric aging product (D-2) exhibit almost the same behavior, and it can be said that the heating resistor stabilization level is at an appropriate level for both. However, -12% electric aging product (D-2)
In many cases, the one showing an abnormal resistance value appeared at the time of applying this. The process yield of the -12% electric aging product was 72%. On the other hand, the process yield of the 500 ° C. heat-treated product (C-1) was 100%. 600 ℃ heat treated product (C-2)
Is a 500 ° C heat-treated product (C-
Although slightly inferior to 1), the life standard was sufficiently satisfied. It is considered to be roughly equivalent to a 600 ° C heat-treated product,-
We also tried to manufacture a 17% electric aging product, but before the decrease in resistance value reached 17%, all the thermal heads showed abnormal resistance values at about 13% to 15%, and it was practically impossible to manufacture it. there were.

In the above embodiment, the heat treatment temperature is 5
00 ° C was the optimum. Even with traditional electric aging,
Trimming by -12% provided the same heat-resistor stabilization effect as the 500 ° C. heat-treated product, but as described above, about 30% of the thermal heads failed due to electric aging.

[0045]

As described above, according to the present invention, in a highly efficient thermal head provided with a polyimide resin layer or the like as a heat retaining layer, it is possible to easily realize uniform resistance values of the heating resistors. Further, even in the case where a heating resistor having a high specific resistance is required to realize high resolution, uniform control of the resistance value becomes very easy. Furthermore, after the heating resistor film is formed, it is subjected to heat treatment to stabilize the resistor film quality, and since it can be stabilized to a level that cannot be achieved by conventional electric aging. In addition to the extremely high process yield, it is possible to omit the conventional electric aging process.
Further, for example, in the case of providing a coercive Mamoruso the polyimide resin, it can be very thin film thickness of the protective layer. Therefore, according to the present invention, a high-efficiency and high-resistance type thermal head provided with a polyimide resin layer as a heat-retaining layer, and a high-resistance thermal head with high resolution in the sub-scanning direction are provided at a stable high yield and at low cost. It becomes possible to produce.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a main part of a thermal head according to an embodiment of the present invention.

FIG. 2 is a graph showing an in-head resistance value distribution of a thermal head according to an embodiment of the present invention.

FIG. 3 is a graph showing an in-head resistance value distribution of a conventional thermal head.

FIG. 4 is a diagram showing the results of pulse withstand life tests of thermal heads that have been subjected to various treatments according to an embodiment of the present invention.

FIG. 5 is a graph showing a typical in-head resistivity distribution of a thermal head according to another embodiment of the present invention.

FIG. 6 is a diagram showing the results of pulse withstand life tests of thermal heads that have been subjected to various treatments according to another embodiment of the present invention.

FIG. 7 is a graph showing an in-head specific resistance value distribution of a conventional thermal head.

[Explanation of symbols]

 1 ... Supporting substrate 2 ... Heat-resistant resin layer 3 ... Protective layer 4 ... Heating resistor 5 ... Heating part 6 ... Conductive layer 7 ... Protective layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01C 17/12 H01C 17/12 (72) Inventor Takashi Ishigami 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Incorporated company Toshiba Yokohama office (72) Inventor Mitsuo Kawai 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Incorporated company Toshiba Yokohama office (56) Reference JP 63-148601 (JP, A) JP Sho 62-56160 (JP, A) JP-A-53-113554 (JP, A) JP-A-63-278205 (JP, A)

Claims (5)

[Claims] 1. A thermal head comprising an insulating support base, a large number of heating resistors formed on the insulating support base, and a conductor connected to each of the heating resistors. The body has 5 to 25 mol% silicon and 1 oxygen.
A thermal head, characterized in that it is contained in the range of 0 to 50 mol% and the balance is substantially formed of a composite body made of Nb or an Nb alloy. 2. A support base and the support base on the heat-resistant resin layer formed, and the coercive Mamoruso provided in the heat-resistant resin layer, a large number of heat-generating resistor formed on this coercive Mamoruso In a thermal head including a body and a conductor connected to each of the heating resistors, the heating resistor contains silicon in an amount of 5 to 2
5 mol%, containing oxygen in the range of 10 to 50 mol% ,
A thermal head characterized in that the balance is substantially formed of a composite body made of Nb or an Nb alloy. 3. When a thermal head is manufactured by forming a large number of heat generating resistors on an insulating support substrate and forming a conductor connected to each of these heat generating resistors, silicon oxide of 15 mol% to In the range of 70 mol%,
A heating target resistor film is formed on the insulating supporting substrate by using a sputtering target whose balance is substantially Nb or Nb alloy, and the heating target resistor film is formed at 200 ° C. to 9 ° C.
A method of manufacturing a thermal head, characterized by performing heat treatment in a temperature range of 00 ° C. 4. The method of manufacturing a thermal head according to claim 3, wherein the heating resistor film is heat-treated in a vacuum of 1 × 10 ⁻¹ Torr or less or in an inert atmosphere. Method of manufacturing thermal head. 5. The method of manufacturing a thermal head according to claim 3, wherein the heat treatment for the heating resistor film is performed before the conductor is formed.