JPH02214671A - Thermal head - Google Patents

Abstract

PURPOSE:To enhance the thermal efficiency and the high-speed thermal response properties of a heat generating resistor by a construction wherein auxiliary current supplying conductor layers formed of a material with a low thermal conductivity is intermediately provided so that the widthwise interval thereof accords with a heat generating part of a heat generating resistor, and the widthwise spacing between a common current supplying conductor layer and a discrete current supplying conductor layer is set to be larger than the widthwise interval of the auxiliary current supplying conductor layers. CONSTITUTION:Auxiliary current supplying conductor layers 9 are formed of Ti, Zr or an alloy thereof which has a thermal conductivity of about 1/10 times that of Al used for common and discrete current supplying conductor layers 4a, 4b. Therefore, heat generated by passing an electric current to a heat generating resistor 3 is hardly transmitted to the conductor layers 4a, 4b. The widthwise spacing L between the current supplying conductor layers 4a and 4b is set to be greater than a heat generating part of a heat generating resistor 3, which construction increases the spacing between the contact part of the layer 4a and the resistor 3 and the contact part of the layer 4b and the resistor 3, so that it becomes more difficult for the heat of the resistor 3 to be transmitted to the layers 4a, 4b, and heat insulating property in the electrode direction at the location of the resistor 3 can be enhanced. It is thereby possible to increase the thermal output of the resistor 3, enhance thermal efficiency in printing, maintain a high printing energy density, and to obtain a high high-speed response property.

Description

[Detailed Description of the Invention] [Field of Industrial Application] °The present invention relates to a thermal head that is installed in a thermal printer and performs desired printing by heating and energizing according to printing information, and particularly relates to an improvement in its thermal characteristics. Ill do it.

(Prior Art) In general, a thermal head installed in a thermal printer has, for example, a plurality of heat generating resistors arranged in a straight line on an insulating substrate, and each of the heat generating resistors is selectively energized according to printed information. It is heated to perform color recording on thermosensitive recording paper, or is used to melt the ink on an ink ribbon and transfer it to plain paper.

Figure 2 shows the general structure of the conventional thermal head of this scale.
A glaze WJ2 made of flat glass that functions as a heat storage layer is formed, and this glaze f! On the upper surface of 2, a plurality of heating resistors 3 made of Ta2N or the like are deposited,
They are formed by being deposited by sputtering or the like and then etching to be aligned in a straight line. A common power supply layer 4a and an individual power supply layer 4b for supplying power to each heat generating resistor 3 are formed on both upper surfaces of each of these heat generating resistors 3, and each of these power supply layers 4a , 4b are made of a soft metal such as All, Cu, or Au, and are formed into a desired pattern by vapor deposition, sputtering, or the like. Each heating resistor 3 is connected to the common power supply layer 4a and the individual power supply layer 4.
A heating area corresponding to one dot, which is the minimum printing unit, is formed between the heating resistors 3 and 4b, and each heating resistor 3 generates heat by applying a voltage between each of the power supply layers 4a and 4b. It is designed so that

A protective layer 5 having a thickness of approximately 7 to 10 μm is formed on the upper surface of the heat generating resistor 3 and the power supply layers 4a and 4b to protect the heat generating resistor 3 and the power supply layers 4a and 4b. Ho 31! ! 5 is an oxidation-resistant layer 6 with a thickness of about 2 μm made of 5ho2 or the like that protects the heating resistor 3 from deterioration due to oxidation, and this oxidized layer 61 is coated with l? The heating resistor 3 and the power supply layer 4a are damaged due to abrasion due to contact with the ink ribbon cap.

Approximately 5-8 μm consisting of 1-a205 etc. that protects 4b
This protection 15 is made up of a wear-resistant layer 7 having a film thickness of 13, and covers the entire surface of each power supply layer 4a, 4b other than the terminal portion.

There is. The oxidation-resistant layer 6 and the wear-resistant layer 7 of this protective layer 5 are
are sequentially formed by means such as sputtering, and then
In the final process, the insulating substrate 1 is divided into 1:1 parts of the desired thermal head f-tube.

In the thermal transfer printer using the conventional adhesive head, the thermal head is brought into pressure contact with the paper via the ink ribbon, and electricity is applied to the individual power supply WJ4b corresponding to the desired heating resistor 3 based on predetermined printing information. As a result, desired printing is performed on the paper by selectively using the heating resistor 3 to melt and transfer ink from the ink ribbon onto the paper.

However, in the conventional multi-head described above, the heat generated in the heat generating resistor 3 due to energization is transmitted in the direction of the glaze wJ2, and approximately 40% of the heat is lost, and each of the power feeders J14a, 4b Approximately 40% of the heat is transferred and lost in the direction.
Only 20% of the heat is used to effectively reduce the printing energy to 1! Therefore, the thermal efficiency decreases considerably, and the printing energy vf! The temperature could not be maintained at a high level, resulting in a large energy loss.

Furthermore, if the thickness of the glaze [12 is made large in order to increase thermal efficiency, glaze II! There was a problem in that the heat capacity opening of No. 12 became large and the heat storage m increased, making it impossible to obtain the high-speed thermal response required for high-speed printing.

FIG. 3 shows a thermal head designed to improve the thermal efficiency of the heat generating resistor, which includes a power supply body 114a,
4b is formed in a 2JI style, and each of the power supply bodies 1m 4a, 4bes is formed into a thin-walled portion 8 near the heat-generating portion of the heat-generating resistor 3.
This is how it is formed.

In this thermal head, each of the power supply layers 4a,
Since the cross-sectional area of each of the power supply layers 4a and 4b can be reduced by the thin wall portion 8 of 4b, the heating resistor 3
The heat from the power supply layer 4a.

The transmission to the 4b side can be somewhat reduced.

(Problems to be Solved by the Invention) By the way, such an improved conventional adhesive head has a thin wall with a pH of 8, so that the unevenness of the heat generating part of the heat generating resistor 3 is made small, and the heat generating part is attached to the platen of the printer. One purpose is to improve the contact property of the
Although heat transfer can be somewhat reduced by the thin wall portion 8, since the power feeders 114a and 4b are made of a material such as Al1 that has extremely high electrical conductivity and thermal conductivity, the heating resistor This method has the problem that the heat transfer of No. 3 cannot be significantly reduced.

Furthermore, it is conceivable to form only the thin part 8 with a material with low thermal conductivity, but since the pattern of the thin part 8 is formed at the same time as the heating resistor 3, the thin part 8 is It is necessary to limit the materials to materials that have good etching selectivity for the heat generating resistor 3, resulting in a problem that the range of material selection is limited.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal head capable of solving the above-mentioned problems of the prior art, increasing the thermal efficiency of a heating resistor, and improving high-speed thermal response.

[Means to solve the problem]

In order to achieve the above object, the thermal head according to the present invention includes a glaze layer formed on an insulating substrate, and a number of meters of heat-generating resistors, each having a longitudinal center portion as a heat-generating portion, arranged on the glaze layer in an array. and a common power supply layer and an individual power supply layer for selectively supplying power to each heat generation resistor are laminated on each of the heat generation resistors, the glaze layer and the heat generation resistor. auxiliary power supply layers made of a material with low thermal conductivity are interposed on both sides of the heat generating part of the heat generating resistor so that the width interval thereof corresponds to the heat generating part of the heat generating resistor; The width interval between the common power supply layer and the individual power supply layers is formed to be larger than the width interval between the auxiliary power supply layers so that the ends of both power supply layers are set back from the end of the auxiliary power supply layer. There is.

[For production]

According to the present invention having the above-described structure, since the auxiliary power supply layer is formed of a material with low thermal conductivity, the heat generated by energizing the heating resistor is difficult to transfer to the glaze layer side. Moreover, since the width interval between both the power supply layers is formed to be larger than the width interval between both the auxiliary power supply layers, the contact portion between the power supply layer and the heat generating resistor becomes distant, and the distance between the heat generating resistor portions increases. The insulation properties in the electrode direction can be significantly improved. Therefore, the heat generation m of the heating resistor increases, the printing thermal efficiency can be significantly increased, the printing energy density can be kept high, high high-speed thermal response can be obtained, and the auxiliary power supply Since the body layer is formed on the lower surface side of the heat generating resistor and the patterning of the auxiliary power supply layer can be performed separately from the heat generating resistor, the material of the auxiliary power supply layer is different from that of the heat generating resistor. It is not necessary to limit the material to a material with good etching selectivity, and it can be formed of any desired material.

〔Example〕

The present invention will be explained below with reference to embodiments shown in the drawings.

FIG. 1 shows an embodiment of a thermal head according to the present invention, in which a glaze layer 2 made of glass, which functions as a heat storage layer, is formed on the upper surface of an insulating substrate 1 made of aluminum or the like. On the upper surface of this glaze layer 2, an auxiliary power supply layer 9 made of Ti, 7R, or alloys thereof, etc., which has a low thermal conductivity of about 1/10 of 81, is formed to a thickness of about 0.3 μm by etching. ing. This auxiliary power supply layer 9 is made of the glaze li! After being formed on the heat generating resistor 2, a pattern is formed by photolithography or the like so that the width interval corresponding to the heat generating portion at the center in the longitudinal direction of the heat generating resistor 3 is 1.

Also, the auxiliary power feeder! On the upper surface of the heating resistor 19, a plurality of heating resistors 3 made of Ta2N or the like and having a heat generating portion in the center in the longitudinal direction are formed in a linear arrangement by vapor deposition, sputtering, etc., and each of these heating resistors An ann for supplying power to each heating resistor 3 is provided on the upper surface of both sides of the body 3.
A common power supply body 114a and an individual power supply body 14b consisting of
are each formed to have a thickness of 2 μm.

Each of the power supply layers 4a and 4b is a power supply layer 4a.

4b is etched by a photolithography technique or the like so that the width interval # is larger than the width interval p of the auxiliary power supply layer 9 so that the end portion of the auxiliary power supply layer F119 is retracted from the end of each auxiliary power supply body F119. The heat generating resistor 3 is exposed, and then the heat generating resistor 3, each of the power feeders VA4a, 4b, and the auxiliary power feeder layer 9 are etched and divided into comb shapes so that the individual parts are aligned. Become. and,
The width interval 1 of the auxiliary power supply layer 9 determines the width dimension of the dots of the heat generating portion of the heat generating resistor 3.

Furthermore, the heating resistor 3 and the power supply layer 4a.

4b, the heating resistor 3 and the power supply layers 4a, 4
A protective layer 5 is formed which protects b from oxidation and wear.

In the thermal transfer printer using the thermal head of the embodiment with the above-described configuration, the thermal head is brought into contact with the paper via an ink ribbon (not shown), and the thermal head is connected to a desired heating resistor 3 based on predetermined printing information. By energizing the individual power supply layer 4b and the auxiliary power supply layer 9, the heating resistor 3 generates heat, and the ink of the ink ribbon is melted and transferred to the paper, thereby making a desired print on the paper. It is supposed to be done.

At this time, the auxiliary power supply layer 9 is connected to each power supply layer 4a, 4b.
7i, which has a thermal conductivity about 1/10 of that of 81 used in
or Lr or an alloy thereof, the heat generated by energizing the heating resistor 3 is difficult to be transmitted to the power supply bodies 14a and 4b, and moreover, the self-supply power interruption 11! Since the width interval between f48°4b is larger than the heat generating part of the heat generating resistor 3, the power supply body ff
The contact area between 148.4b and the heating resistor 3 becomes distant,
The heat of the heat generating resistor 3 becomes difficult to be transmitted to each power supply layer 4a, 4bll, and the temperature of the heat generating resistor aalS becomes t'
The insulation properties in the electrode direction can be significantly improved.

In this way, in this embodiment, the heat insulation properties of the heat generating resistor 3 portion in the electrode direction can be greatly improved, so the heat generating portion of the heat generating resistor 3 increases, and the printing thermal efficiency is significantly improved. It can increase printing energy density, maintain high printing energy density, and provide high-speed thermal response. ? can be done. In addition, since the width interval between the two power feeders 1!14a and 4b is formed large, the unevenness of the heat generating part of the heat generating resistor 3 can be made small, and the heat generating part to the platen of the printer can be formed small. It is possible to reverse the contact property of C. Furthermore, the auxiliary power supply layer 9 is formed on the lower surface side of the heating resistor 3, and the patterning of the auxiliary power supply WJ9 can be performed separately from the heating resistor 3. There is no need to limit the material of the feeder layer 9 to materials with good etching selectivity with respect to the heating resistor 3, and the auxiliary power feeder layer 9 may be made of Ti or 2'.
Or when using those alloys - 6, the auxiliary power supply II! 9 can be formed satisfactorily.

Note that the present invention is not limited to the above embodiments,
Various changes can be made as necessary. For example, various other materials can be selected as the material of the auxiliary power supply body 1lI9 as long as it has a low thermal conductivity.

(Effects of the Invention) As described above, according to the thermal head according to the present invention, it is possible to reduce the transfer of heat of the heating resistor to each power supply layer side, and the heat generating resistor portion 1 can be reduced. Since the thermal insulation properties in the force direction can be moderated, the heat generation of the heating resistor will increase, the printing thermal efficiency can be significantly increased, and the printing energy density can be maintained high. This has the effect that high high-speed thermal response can be obtained.

FIGS. 2 and 3 are longitudinal sectional views of a conventional linear head, respectively.

DESCRIPTION OF SYMBOLS 1... Insulating substrate, 2... Glaze layer, 3... Heat generating resistor, 4a... Common power supply layer, 4b... Individual power supply layer, 5... Protective layer, 9. ...Auxiliary power supply layer.

Claims (1)

[Claims] A glaze layer is formed on an insulating substrate, a plurality of heating resistors each having a longitudinal center portion as a heating portion are formed in an array on the glaze layer, and each heating resistor is placed on each of the heating resistors. In a thermal head formed by laminating a common power supply layer and individual power supply layers for selectively supplying power to the
Between the glaze layer and the heat generating resistor, auxiliary power supply layers made of a material with low thermal conductivity are provided on both sides of the heat generating part of the heat generating resistor, and the width interval thereof is the same as the heat generating part of the heat generating resistor. The common power supply layer and the individual power supply layers are arranged so that the width interval between the common power supply layer and the individual power supply layer is set to the width interval between the auxiliary power supply layers so that the ends of both power supply layers are set back from the end of the auxiliary power supply layer. A thermal head characterized by being larger.