JPH10151784A - Thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal head which can be improved in heat resistance. SOLUTION: The thermal head comprises a stainless substrate 21 having a long common electrode part 22 projected on a surface thereof, a first glaze glass 241 formed at a left surface of the stainless substrate 21 at the left side of the common electrode part 22, a second glaze glass 242 formed at a right surface of the stainless substrate 21 at the right side of the common electrode part 22, a heat-generating resistance body 25 formed all over surfaces from the first glaze glass 241 to the second glaze glass 242 through the common electrode part 22, a first independent electrode 261 formed on the surface of the first glaze glass 241 and a second independent electrode 262 formed on the surface of the second glaze glass 242 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermal head suitable for use in a thermal printer.

[0002]

2. Description of the Related Art FIG. 4 is a side view showing a configuration of a printing section of a thermal printer to which a conventional thermal head is applied. The thermal printer performs full-color printing on printing paper by combining, for example, three sublimation inks of yellow, magenta, and cyan.

In FIG. 4, reference numeral 1 denotes a platen roller which is sequentially rotated by an angle corresponding to one line by a drive motor (not shown). 2 is a printing paper,
The platen roller 1 conveys one line at a time. 3 is a color ink ribbon, the surface of which is
The above-described yellow ink, magenta ink, and cyan ink are repeatedly applied.

[0004] These yellow inks and the like have the property of sublimating when grayscale energy is applied in addition to bias energy. Here, the bias energy refers to the energy required for the yellow ink or the like to start sublimation, while the gradation energy refers to the energy for controlling the color density of the yellow ink or the like on the printing paper 2. That is, the sublimation rate of the yellow ink or the like is determined according to the applied gradation energy. Reference numeral 4 denotes a thermal head having a plurality of heating resistors each corresponding to one dot, and applies energy generated by a supplied current to the color ink ribbon 3. The thermal head 4 has a so-called double-line configuration.

Here, the configuration of the above-described thermal head 4 will be described with reference to FIGS. FIG.
FIG. 6 is a plan view showing the configuration of the thermal head 4, and FIG.
FIG. 6 is a sectional view taken along line AA ′ shown in FIG. 5. In FIG. 5, reference numeral 51 denotes a first alumina substrate. Reference numeral 52 denotes a second alumina substrate which is opposed to the first alumina substrate 51 at a predetermined interval. Reference numeral 6 denotes a metal plate interposed between the first alumina substrate 51 and the second alumina substrate 52. As shown in FIG. 6, the upper end 6a has the first alumina substrate 51 and the second alumina substrate 52. It is provided so as to slightly protrude from the respective surfaces 51a and 52a of the alumina substrate 52.

The first alumina substrate 51, the second alumina substrate 52 and the metal plate 6 are integrated by metallizing. Reference numeral 71 denotes a first glass grace substrate formed on the surface 51a of the first alumina substrate 51 on the left side of the figure from the metal plate 6. A second glass grace substrate 72 is formed on the surface 52a of the second alumina substrate 52 on the right side of the figure from the metal plate 6.

.. Shown in FIG. 5 are a plurality of first heating resistors provided corresponding to one dot, respectively.
6 are formed on the surface of the first glass grace substrate 71 on the left side of the metal plate 6 shown in FIG. 6 at regular intervals by sputtering. These first heating resistors 8
1, 81,... Apply energy (Joule heat) generated according to the supplied current to the color ink ribbon 3 (see FIG. 4).

Are heat generating resistors 81, 81,...
.. Are a plurality of first individual electrodes provided respectively corresponding to. And are formed on the surface of the first alumina substrate 51 at regular intervals. One end of the first individual electrode 91 is electrically connected to one end 81a of the first heating resistor 81 shown in FIG.

.. Shown in FIG. 5 are a plurality of second heating resistors provided corresponding to one dot, respectively, and are the same as those of the metal plate 6 shown in FIG. They are formed at regular intervals by sputtering on the surface of the second glass grace substrate 72 on the right side. The second heating resistors 82, 82,... Transfer energy (Joule heat) generated according to the supplied current to the color ink ribbon 3.
(See FIG. 4).

, 92, 92,... Are second heat generating resistors 82,
Are a plurality of second individual electrodes provided in correspondence with 82,... Respectively, and are formed at regular intervals on the surface of the second alumina substrate 52. One end of the second individual electrode 92 is connected to one end 82 of the second heating resistor 82 shown in FIG.
a. Reference numeral 10 denotes a common electrode provided along the metal plate 6, and has a rear surface 10 shown in FIG.
a is electrically connected to the upper end surface 6b of the metal plate 6.

The common electrode 10 is electrically connected to the other end 81b of the first heating resistor 81 and the other end 82b of the second heating resistor 82, respectively. That is, the first heating resistor 81 has one end 81a and the other end 81b.
Other parts actually act as resistors. On the other hand, the second
In the heating resistor 82, the portion other than the one end portion 82a and the other end portion 82b actually acts as a resistor.

In FIG. 6, reference numeral 11 denotes a first individual electrode 91,
A protective film formed on each surface of the first heating resistor 81, the common electrode 10 and the like.
It serves to protect the first individual electrode 91, the second individual electrode 92, the common electrode 10 and the like from abrasion caused by contact with the electrodes. In FIG. 5, illustration of the protective film 11 is omitted.

Reference numeral 121 shown in FIG. 5 denotes a first control IC (Integ) provided on the surface of the first alumina substrate 51.
rated circuit), and the first individual electrodes 91, 91, ...
Has a plurality of terminals respectively corresponding to. These terminals are electrically connected to the other ends of the first individual electrodes 91, 91,..., Respectively.
Reference numeral 21 denotes a first pulse voltage having a pulse width corresponding to the first print data based on the first print data supplied from a control unit (not shown).
Are applied to the first heating resistors 81, 81,.

Reference numeral 122 denotes a second control IC provided on the surface of the second alumina substrate 52, and has a plurality of electrodes respectively corresponding to the second individual electrodes 92, 92,... . These terminals are connected to the second individual electrodes 92, 92,
Are electrically connected to the other ends, respectively. Based on the supplied second print data, the second control IC 122 has a pulse width corresponding to the second print data. The second pulse voltage is applied to the second individual electrodes 92, 92,.
Are applied to the second heating resistors 82, 82,.

FIG. 7 is a circuit diagram showing an electrical configuration of the above-described conventional thermal head. In this figure, FIG.
The same reference numerals are given to the portions corresponding to the respective portions. 7, the common electrode 10 (see FIG. 5) is grounded. The first control IC 121 applies a first pulse voltage V1 having a pulse width corresponding to the input first print data DATA1 to the first heating resistors 81, 81,.
Is applied or not applied.

The switching control includes a first clock signal CLOK1 input from a control unit (not shown) and a first clock signal CLOK1.
Print data DATA1, the first latch signal LATCH
1 and the first strobe signal STROB1. 131 is the ground and the first control IC 1
A first pulse voltage V1 supplied to the first heating resistors 81, 81,... Which is a first DC power supply interposed between the input terminals 21 and 21 (not shown). It is.

The second control IC 122 applies a second pulse voltage V2 having a pulse width corresponding to the input second print data DATA2 to the second heating resistors 82, 82,... Or switching control of not applying voltage is performed.

The switching control includes a second clock signal CLOK2 and a second clock signal
Print data DATA2, the second latch signal LATCH
2 and the second strobe signal STROB2. 132 is a ground and second control IC 1
A second DC power supply interposed between the input terminals 22 and 22 (not shown), and a voltage source of a second pulse voltage V2 supplied to the second heating resistors 82, 82,... It is.

In the above configuration, the thermal head 4
However, in a state of being pressed against the platen roller 1 via the color ink ribbon 3 and the printing paper 2, one line portion of the color ink ribbon 3 (printing paper 2) is the first heating resistor 81 shown in FIG. , 81,... And 2 of the color ink ribbon 3 (printing paper 2).
The line portion is the second heating resistor 82, 82, shown in FIG.
It is assumed that it is located immediately above.

In the above state, the first control IC 121 shown in FIG.
At the timing of the first print data DATA of the first line
1 and the first print data DATA of the first line at the timing of the first latch signal LATCH1.
1 is latched by a latch circuit (not shown).

And now, the first strobe signal STR
When OB1 becomes “high”, the first control IC1
21 is a first heating resistor 8 based on the first print data DATA1 latched by the latch circuit at the timing of the first strobe signal STROB1.
A first pulse voltage V1 is applied to 1, 81,.
Here, the pulse width of the first pulse voltage V1 is as shown in FIG.
Is the value of the bias pulse width PB + the gradation pulse width PG shown in FIG. The bias pulse width PB is a value corresponding to the aforementioned bias energy. On the other hand, the gradation pulse width PG is a value corresponding to the gradation energy, and the change in the gradation pulse width PG corresponds to a change in the gradation from 0 to 255 gradations.

Thus, the first heating resistors 81, 81,
Generate Joule heat, and as a result, energy corresponding to the Joule heat is applied to one line portion of the color ink ribbon 3 (see FIG. 4). Thereby, the ink on one line portion of the color ink ribbon 3 sublimates,
A color having a desired color density is generated on one line portion of the printing paper 2.

On the other hand, in parallel with the above-described printing operation for one line portion of the printing paper 2, the second control IC 122 shown in FIG. 7 performs the second printing of the second line at the timing of the second clock signal CLOK2. Data DATA2
After reading the second print data DATA2 on the second line at the timing of the second latch signal LATCH2.
Are latched by a latch circuit (not shown).

Now, the second strobe signal STR
When OB2 becomes "high", the second control IC1
22 is a second heating resistor 8 based on the second print data DATA2 latched by the latch circuit at the timing of the second strobe signal STROB2.
A second pulse voltage V2 is applied to 2, 82,.
As a result, Joule heat is generated in the second heating resistors 82, 82,...
The energy corresponding to the Joule heat is applied to the two line portions (see FIG. 4). As a result, the ink on the two lines of the color ink ribbon 3 sublimates, and the printing paper 2
In the two lines, a color having a desired color density is generated.

Then, 1 and 2 of the above-described printing paper 2
When the printing on the line portion is completed, the platen roller 1 shown in FIG. 4 is driven to rotate by an angle corresponding to one line, and in conjunction with this, the color ink ribbon 3 and the printing paper 2 are conveyed by one line. As a result, the two line portions of the color ink ribbon 3 (printing paper 2) are located immediately above the first heating resistors 81, 81,... Shown in FIG. Are located immediately above the second heating resistors 82, 82,....
Then, in the same manner as the above-described operation, the printing operation is performed on the 2 and 3 line portions of the printing paper 2.

Here, the line printing time tL required for printing one line portion of the printing paper 2 is expressed by the following equation (1). tL = PB + PG (1) In the above equation (1), PB is the pulse width PB for bias shown in FIG. 9, and P G is the pulse width P G for gradation shown in FIG. is there. The page printing time tp required to print one page on the printing paper 2 is expressed by the following equation (2). tP = tL × L × 3 (2) In the above equation (2), L is the total number of lines on the printing paper 2, and “3” is yellow, magenta, and cyan. This is the number of colors used for printing. The actual actual printing time is a time obtained by adding the paper loading time, the paper discharging time, and the like to the page printing time tp. According to the method of driving the thermal head 4 described above, the printing time can be reduced in principle by half compared to the method of driving the single-line thermal head.

In the thermal head 4 described above, in addition to the above-described driving method, the first heating resistors 81, 81,... After applying the pulse voltage V1, the second heating resistor 82, 82,.
The driving method of applying the pulse voltage V2 is also applicable.

According to the other driving method, the printing time can be reduced by 0.83 to 0.66 times as compared with the driving method of the single-line thermal head. Here, the single-line thermal head is a thermal head having only the first heating resistors 81, 81,... Shown in FIG. Therefore, this single-line thermal head can print only one line at a time.

FIG. 8 is a sectional view showing another example of the structure of a conventional thermal head. In this figure, parts corresponding to the respective parts in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted. 8, the first alumina substrate 5 shown in FIG.
1, an alumina substrate 14 and a metal plate 15 are provided instead of the second alumina substrate 52 and the metal plate 6.

On the alumina substrate 14 shown in FIG. 8, a groove 14a having a concave cross section is formed in a portion corresponding to the common electrode 10. The metal plate 15 is fitted into the groove 14 a of the alumina substrate 14 such that its upper end 15 a slightly projects from the surface 14 a of the alumina substrate 14. The common electrode 10 is provided on the upper end surface 15b of the metal plate 15.
Are electrically connected to each other.

[0031]

Incidentally, the above-described double-line thermal head has the advantage that the printing time can be shortened theoretically as compared with the single-line thermal head, but will be described below. There was a problem that it was not practically used due to a serious disadvantage. That is, the first alumina substrate 51 and the second alumina substrate 52 shown in FIG. 6 and the metal plate 6 have different thermal expansion coefficients due to the difference in material. The thermal head 4
Are subjected to a heat treatment of about 400 ° C. in the manufacturing process, and further, at the time of printing, the first heating resistors 81, 81,.
And the temperature of the second heating resistors 82, 82, ... reach a maximum of 600 ° C.

Accordingly, at the time of the high temperature, the first alumina substrate 51 and the second alumina substrate 52 and the metal plate 6 expand with different coefficients of thermal expansion. As a result, a thermal strain due to the above-described difference in the thermal expansion coefficient occurs on the joint surface between the first alumina substrate 51 and the second alumina substrate 52 and the metal plate 6, and in the worst case, the first The alumina substrate 51 and the second alumina substrate 52 are separated from the metal plate 6.

Further, since the mechanical strength of the common electrode 10 shown in FIG. 6 is extremely low, the common electrode 10 is broken at the time of the above-described peeling. Therefore, in the worst case, the common electrode 10 is disconnected from the first heating resistors 81, 81,... And the second heating resistors 82, 82,. That is, the above-described conventional thermal head has a defect that it lacks heat resistance. The present invention has been made under such a background, and has as its object to provide a thermal head capable of improving heat resistance.

[0034]

According to a first aspect of the present invention, there is provided a substrate having a common electrode portion having a predetermined length protrudingly formed on a central surface thereof, and a substrate having a common electrode portion on one side of the common electrode portion. A first insulator formed on the surface, a second insulator formed on the surface of the substrate on the other side from the common electrode portion, and a second insulator formed on the surface of the first insulator, and One end is formed on the surface of the first heating resistor electrically connected to the common electrode portion and the surface of the second insulator, and one end is electrically connected to the common electrode portion. And a second heating resistor.

According to a second aspect of the present invention, in the thermal head according to the first aspect, an output terminal of the thermal head is connected to the other end of the first heating resistor. A first control means for applying a first pulse voltage having a pulse width corresponding to print data between the other end and the common electrode, and an output terminal connected to the other of the second heating resistor A second control that is connected to an end and applies a second pulse voltage having a pulse width corresponding to the print data between the other end of the second heating resistor and the common electrode unit; Means.

According to a third aspect of the present invention, in the thermal head according to the first or second aspect, the substrate is formed of a stainless steel material.

According to a fourth aspect of the present invention, in the thermal head according to the first or second aspect, the first insulator and the second insulator are both formed of a glass material. And

[0038]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cut perspective view showing an external configuration of a thermal head according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line BB ′ shown in FIG.
In the thermal head 20 shown in FIG. 1, for example, a stainless substrate 21 having a thickness of 0.8 mm has a long common electrode portion 22 protruding from the surface of the stainless substrate 21. The height of the common electrode section 22 is 50
μm. 23 is a grace glass formed on the back surface of the stainless steel substrate 21.

Reference numeral 241 denotes a first grace glass formed on the left surface of the stainless steel substrate 21 on the left side of the common electrode portion 22 shown in FIG. 2, and a portion near the common electrode portion 22 is bulged. 24
1a. Reference numeral 242 denotes a second grace glass formed on the right surface of the stainless steel substrate 21 on the right side of the drawing with respect to the common electrode portion 22, and a portion near the common electrode portion 22 is formed to be bulged.
It has been.

Reference numeral 25 denotes a heating resistor, which is formed on each surface from the first grace glass 241 to the second grace glass 242 via the common electrode portion 22.
The heating resistors 25 are provided corresponding to one dot, and a plurality of the heating resistors 25 are actually provided at regular intervals. In the heating resistor 25, a portion of the common electrode portion 22 that contacts the surface 22a is electrically connected to the surface 22a.

Reference numeral 261 denotes a first individual electrode formed on the surface of the first grace glass 241;
It is electrically connected to one end of the heating resistor 25. The other end of the first individual electrode 261 is connected to a terminal of a first control IC (not shown). The first control IC is a first control IC shown in FIG.
It has the same function as C121.

Reference numeral 262 denotes a second individual electrode formed on the surface of the second grace glass 242.
It is electrically connected to the other end of the heating resistor 25. The other end of the second individual electrode 262 is connected to a terminal of a second control IC (not shown). The second control IC is the second control IC shown in FIG.
It has the same function as C122.

Reference numeral 27 denotes a common electrode disposed along the common electrode portion 22 shown in FIG. 1, and the back surface thereof is electrically connected to the surface of the heating resistor 25 shown in FIG. I have. That is, in the heating resistor 25 shown in FIG. 2, a portion that is not joined to the first individual electrode 261 and the common electrode 27 actually acts as a heating resistor.
This portion is referred to as a first heating resistor 251. Further, in the heating resistor 25, a portion not joined to the second individual electrode 262 and the common electrode 27 actually acts as a heating resistor, and this portion is hereinafter referred to as a second heating resistor 25.
Called 2.

That is, the thermal head 20 shown in FIG.
Has a plurality of first heating resistors 251, 251,... And a plurality of second heating resistors 252, 252,. Reference numeral 28 shown in FIG. 2 is a protective film covering the entire surface of the first individual electrode 261 and the like. In FIG. 1, illustration of the protective film 28 is omitted. The operation of the thermal head 20 according to the above-described embodiment is described below.
Since it is the same as the above-described conventional thermal head, its description is omitted.

Next, a method for manufacturing the thermal head 20 according to the above-described embodiment will be described with reference to FIGS. First, the stainless steel substrate 21 shown in FIG.
Is degreased and washed with an organic solvent such as n-propyl bromide, and then washed with a scrubber. As a result, dust and the like adhering to the front and back surfaces of the stainless steel substrate 21 are removed.

Next, the stainless steel substrate 21 is immersed in a cleaning solution of methyl bromide and then subjected to ultrasonic cleaning. As a result, dust adsorbed on the minute uneven portions on the front and back surfaces of the stainless steel substrate 21 is removed. Next, in order to polish the front and back surfaces of the stainless steel substrate 21, for example, FeCl ₃ : 50 g, HHl: 50.
0 ml and H ₂ O: immersed in 1000 ml of a ferric chloride solution for 2 minutes. Thus, the front and back surfaces of the stainless steel substrate 21 are polished by a gentle etching action.

When the polishing process is completed, the entire surface of the stainless steel substrate 21 is coated with a photoresist. When the coating process is completed, the common electrode portion 22 is formed by photolithography.
After a mask is applied to a portion where is to be formed, a photoresist is patterned by photolithography. Thereby, in the stainless steel substrate 21,
The photoresist remains only in the portion where the common electrode section 22 is to be formed.

Next, the stainless steel substrate 21 is made of H ₂ C ₂ O ₄
After being immersed in an oxalic acid solution of 2H ₂ O: 200 g + H ₂ O: 2000 ml, a voltage of 5 V is applied between the electrodes with an electrode interval (not shown) of 20 mm. As a result, an unmasked portion of the stainless steel substrate 21 is etched at an etching rate of about 0.67 μm / min. As a result, the unetched portion remains as the common electrode portion 22. That is, the common electrode portion 22 is gradually formed as the etching process proceeds. During the etching process, the height of the formed common electrode portion 22 is measured by a surface roughness measuring device. When the surface of the common electrode portion 22 is rough in a state where the above-described etching process is completed, the common electrode portion 22 is polished with a grindstone.

Next, the stainless steel substrate 21 was heated at 900.degree.
Bake for 0 minutes. Thereby, the stainless steel substrate 21
An oxide film is formed on the surface of the substrate. When the baking process is completed, the first glass paste 241b is screen-printed to a thickness of 20 μm on the left surface of the stainless steel substrate 21 on the left side of the common electrode portion 22 shown in FIG. Similarly, a second glass paste 242b is screen-printed to a thickness of 20 μm on the right surface of the stainless steel substrate 21 on the right side of FIG.

Here, the first glass paste 2 described above is used.
41b and the second glass paste 242b refer to a mixture of a solvent and glass powder. Then, the first
When the screen printing of the glass paste 241b and the second glass paste 242b is completed, each of these surfaces is flattened by leveling.

Next, a pre-baking process of heating the first glass paste 241b and the second glass paste 242b to a relatively low temperature of 140 ° C. in a furnace is performed. Here, the above 140 ° C. is a temperature at which the solvent contained in the first glass paste 241 b and the like is gradually volatilized without bumping. When the pre-baking process is performed, the solvent contained in the first glass paste 241b and the second glass paste 242b gradually evaporates.

When the above-mentioned pre-baking process is completed, the stainless steel substrate 21 is taken out of the furnace, and the stainless steel substrate 21 (the first glass paste 241b or the like) is removed.
Is naturally cooled from the above 140 ° C. to room temperature. next,
After the glass paste 23a is screen-printed with a certain thickness on the back surface of the stainless steel substrate 21, the glass paste 2
The surface of 3a is flattened.

When the above-described flattening process is completed, the pre-baking process is performed at 140 ° C. as described above. Thereby, the solvent contained in the glass paste 23 screen-printed on the back surface of the stainless steel substrate 21 gradually evaporates. Next, the stainless substrate 21 is fired at 850 ° C. for 10 minutes, and then naturally cooled to room temperature. As a result, the first glass paste 241b and the second glass paste 242b become
Each is made of grace glass, and the glass paste 23a is made of grace glass 23 (see FIG. 2).

Next, using a metal mask, the first partial glass paste 241c and the first partial glass paste 241c are applied to both side walls of the common electrode portion 22 and both surfaces of the glaze glass at both portions of the common electrode portion 22 shown in FIG. Second partial glass paste 242c
Are each screen printed at a thickness of 30 μm. When the screen printing is completed, the first partial glass paste 241 c and the second partial glass paste 2
The surface of 42c is prepared.

Next, the first partial glass paste 241c
And the second partial glass paste 242c etc.
The prebaking is performed at a temperature of ℃, whereby the solvent contained in the first partial glass paste 241c and the like volatilizes.

When the pre-baking process is completed, the stainless steel substrate 21 is subjected to a baking process for 10 minutes in a furnace at a temperature of 950 ° C. As a result, the first partial glass paste 241c and the glass lace thereunder are integrated, and as a result, the first grace glass 241 having a raised portion 241a shown in FIG.
Is formed. At the same time, the second partial glass paste 242c shown in FIG. 3 and the glass grace thereunder are integrated, and as a result, the raised portion 2 shown in FIG.
A second grace glass 242 having 42a is formed. Here, the surface H including the common electrode portion 22 shown in FIG. 3 is polished as necessary. Thereby, the excess glass grace and the oxide film on the surface of the common electrode portion 22 are removed.

Next, the surfaces of the first grace glass 241 and the second grace glass 242 formed on the stainless steel substrate 21 shown in FIG.
A resistor film of, for example, TaSiO ₂ is formed on the surface of the substrate by sputtering so as to have a predetermined sheet resistance value. Next, on this resistor film, for example, NiCr is deposited in a thickness of 0.1 μm by an electron beam evaporation method.

Next, a photoresist is patterned by photolithography according to the shape of the heating resistor 25 shown in FIG. And the stainless steel substrate 2
1 is immersed in a cerium ammonium nitrate solution, using the photoresist pattern as a mask,
The above-described NiCr is etched. Then, the photoresist is removed, whereby the NiCr is patterned into the shape of the heating resistor 25.

Next, the resistor film is etched using NiCr as a mask. Thereby, the above-described resistor film is patterned into the shape of the heating resistor 25. Next, a binder thin film is formed on the surface of the heating resistor 25 to a thickness of 0.1 μm. The binder thin film includes a heating resistor 25 shown in FIG. 2, a first individual electrode 26 1, and a common electrode 27.
In addition, it has a function of improving the adhesion between the second electrode 262 and the second individual electrode 262.

Next, an aluminum film is deposited on the surface of the first heating resistor 251 by an electron beam evaporation method. When the vapor deposition is completed, the first individual electrode 2
The photoresist is patterned by photolithography so that the photoresist remains on the surface of the first heating resistor 251 corresponding to 61, the second individual electrode 262, and the common electrode 27.

Next, the stainless steel substrate 21 is immersed in an etching solution (phosphoric acid). Thereby, the first heating resistor 2
The portion 51 of the photoresist other than the mask is etched. By removing the photoresist, the first individual electrode 261 and the second individual electrode 262 are removed.
And a common electrode 27 are formed. Next, the entire surface of the first individual electrode 261, the first heating resistor 251, etc.
For example, SIALON (registered trademark) is formed with a thickness of 5 μm by sputtering. Thus, a protective film 28 is formed.

When the above processing is completed, the thermal head 20 shown in FIG.
Time). Next, although not shown in the drawing, an insulating film is deposited on the first IC arrangement area in the first individual electrodes 261, 261,... Shown in FIG. A first control IC (not shown) is die-bonded on the region of the insulating film. Then, each terminal of the first control IC and the corresponding first individual electrode 261, 261,... Are wire-bonded.

On the other hand, the second individual electrodes 262, 262,...
An insulating film is deposited in the second IC arrangement area in
A second control IC (not shown) is die-bonded on the insulating film in the second IC region. And
Each of the terminals of the second control IC and the corresponding second individual electrodes 262, 262,... Are wire-bonded. Then, as a final step, the wire bond portions of the first and second control ICs and the first individual electrodes 26 1, 26 1,.
.. Are partially sealed with epoxy resin.

As described above, according to the thermal head according to the above-described embodiment, the stainless substrate 21 and the common electrode portion 22 are formed of the same material having the same coefficient of thermal expansion. In addition, the effect of reducing the rate of occurrence of disconnection due to separation or the like due to a difference in the coefficient of thermal expansion can be obtained. That is, according to the thermal head according to the above-described embodiment, the effect that the heat resistance can be improved can be obtained.

Further, the inventor conducted an experiment in comparison with a conventional thermal head in order to quantitatively know the heat resistance effect of the thermal head according to one embodiment. The experimental results are shown below. First, as a sample for this experiment,
The following samples 1 to 3 are used. (A) Sample 1 (thermal head 20 according to one embodiment shown in FIG. 1) (b) Sample 2 (conventional thermal head shown in FIG. 8) (c) Sample 3 (single-line thermal head described above)

As an experimental method, each sample was heated (A) to 400 ° C. in an electric furnace, (B) immersed in water at 20 ° C., and (C) the disconnection of the pattern due to surface cracks was examined. After observation and evaluation using a magnifying glass, if (D) the above disconnection does not occur, the temperature is increased by 10 ° C. in (A), and (A) to (C) are repeated. Was used. The results of this experiment are shown below. (Sample) (Average temperature in furnace when disconnection occurred) Sample 1 800 ° C Sample 2 400 ° C or less Sample 3 460 ° C As is clear from the above experimental results, heat resistance of thermal head (sample 1) according to one embodiment It can be seen that the characteristics are significantly improved as compared with the conventional thermal head (samples 2 and 3).

As described above, one embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and a design change within a range not departing from the gist of the present invention. The present invention is also included in the present invention. For example, in the method of manufacturing a thermal head according to the above-described embodiment, the common electrode portion 2 shown in FIG.
Although the method of forming 2 has been described, instead of this method, a method of polishing, rolling, pressing or drawing the stainless steel substrate 21, or a combination of these processing methods may be used.

[0068]

According to the present invention, since the common electrode portion is formed on a substrate made of the same material as the common electrode portion, disconnection due to separation due to a difference in coefficient of thermal expansion occurs as in a conventional thermal head. The effect that it is difficult to obtain is obtained. That is,
ADVANTAGE OF THE INVENTION According to this invention, the effect that heat resistance can be improved is acquired.

[Brief description of the drawings]

FIG. 1 is a partially cut perspective view showing an external configuration of a thermal head according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line B-B 'shown in FIG.

FIG. 3 is a diagram illustrating a method for manufacturing a thermal head according to an embodiment of the present invention.

FIG. 4 is a side view showing a configuration of a printing unit of a thermal printer to which a conventional thermal head is applied.

FIG. 5 is a plan view showing an external configuration of a conventional thermal head.

6 is a sectional view taken along line A-A 'shown in FIG.

FIG. 7 is a circuit diagram showing an electrical configuration of a conventional thermal head.

FIG. 8 is a cross-sectional view showing another configuration example of a conventional thermal head.

FIG. 9 is a characteristic diagram showing a color density characteristic of the color ink ribbon 3 shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 Thermal head 21 Stainless steel substrate 22 Common electrode part 23 Grace glass 241 1st Grace glass 242 2nd Grace glass 251 1st heating resistor 252 2nd heating resistor 261 1st individual electrode 262 2nd individual Electrode 27 Common electrode

Claims (4)

[Claims] A substrate having a common electrode portion of a predetermined length protrudingly formed on a central surface thereof; a first insulator formed on a surface of the substrate on one side of the common electrode portion; A second insulator formed on the surface of the substrate on the other side of the common electrode portion; and a second insulator formed on the surface of the first insulator and having one end electrically connected to the common electrode portion. And a second heating resistor formed on the surface of the second insulator and having one end electrically connected to the common electrode portion. Characteristic thermal head. 2. An output terminal connected to the other end of the first heating resistor, and a print data between the other end of the first heating resistor and the common electrode portion. First control means for applying a first pulse voltage having a corresponding pulse width, and an output terminal connected to the other end of the second heating resistor, the other end of the second heating resistor And a second electrode having a pulse width corresponding to the print data between the common electrode section and the common electrode section.
2. The thermal head according to claim 1, further comprising a second control unit that applies the pulse voltage of (1). 3. The thermal head according to claim 1, wherein the substrate is formed of a stainless steel material. 4. The thermal head according to claim 1, wherein both the first insulator and the second insulator are formed of a glass material.