JP4895344B2

JP4895344B2 - Heating resistance element, thermal head and printer using the same

Info

Publication number: JP4895344B2
Application number: JP2005274899A
Authority: JP
Inventors: 義則佐藤; 利光師岡; 法宜東海林
Original assignee: セイコーインスツル株式会社
Priority date: 2005-09-22
Filing date: 2005-09-22
Publication date: 2012-03-14
Anticipated expiration: 2025-09-22
Also published as: JP2007083532A

Description

The present invention relates to a heating resistor element, a thermal head using the same, and a printer .

The heating resistor element is used for, for example, a thermal head of a thermal printer. Generally, a heat storage layer made of glass or the like is laid on a substrate made of alumina ceramic or the like, and a plurality of heating resistors are formed thereon. It is set as the structure which provided.

Here, the thermal printer is a general term for a thermal transfer printer that heats and melts ink with a thermal head and transfers it to a printing target, a direct thermal printer that directly heats thermal paper with a thermal head, and the like.

A thermal printer selectively generates heat in each heating resistor of a thermal head and applies heat to a desired position of a heating target such as an ink ribbon or thermal paper, thereby melting the ink in a desired pattern. The image is transferred to a print target or the thermal paper is heated in a desired pattern.

In devices using such heating resistance elements, in recent years, power-saving products that can be driven by a battery, with a focus on small and lightweight portable applications, are becoming widespread. In addition, due to the energy situation from the viewpoint of environmental considerations etc., the movement of power saving is active, such as aiming at zero standby power even in stationary electronic devices that do not use batteries, increasing energy efficiency. It has become essential.

In the conventional heating resistor element, most of the heat generated by the heating resistor is transmitted to the substrate side through the material constituting the heating resistor element or the heat storage layer without contributing to the heat treatment for printing or the like. It is said that it is closed.

For this reason, the heat generated by the heating resistor is effectively utilized for heat treatment such as printing without being transmitted to the substrate as much as possible (that is, by increasing the heating efficiency), thereby reducing the power consumption of the heating resistor. Is considered.

In addition, when the thermal head performs printing output continuously, heat is continuously transmitted to the substrate, so that the heat radiation of the substrate cannot be made in time, and the entire thermal head becomes extremely hot. This temperature rise causes a drop in print quality, and thus it is necessary to increase the heat generation efficiency of the thermal head in order to realize high-quality continuous printing.

As a thermal head with improved heat generation efficiency, for example, one having a structure shown in Patent Document 1 described later has been devised. This thermal head has a plurality of heating resistors arranged at intervals on the surface of an insulating substrate consisting of an insulating substrate body and an underglaze layer formed on the surface of the insulating substrate body. It has a structure in which wiring for supplying power to the body is laid. By providing a strip-shaped cavity extending in the arrangement direction of the heating resistors at an intermediate position in the thickness direction of the underglaze layer, the strip-shaped cavity functions as a heat insulating layer having a low thermal conductivity, thereby generating a heating resistor. It is considered to improve the heat generation efficiency by reducing the amount of heat flowing from the body to the insulating substrate side.

The band-shaped cavity is formed in the underglaze layer by embedding the band-shaped cellulosic resin when the underglaze layer is formed, and evaporating the cellulosic resin during the baking process. .
JP-A-6-166197

However, the thermal head of Patent Document 1 has the following problems.

First, by providing a hollow portion under the heating resistor, there is a heat insulation effect toward the insulating substrate body, but the underglaze layer itself is relatively formed in order to form the hollow portion at an intermediate position in the thickness direction. It needs to be thick. For this reason, the amount of heat transferred to the underglaze layer is accumulated in the underglaze layer, and the amount of heat transferred to the surface side of the heating resistor is small, so the heat generation efficiency is low.

Second, the dimensional accuracy of the resin material that is evaporated to form the cavity is low, and it is not possible to form a precisely shaped cavity. For this reason, since the cavity is formed in a strip shape so as to straddle the plurality of heating resistors along the arrangement direction of the plurality of heating resistors, the strength of the underglaze layer at the position of the heating resistors is low, and printing is performed. At this time, the cavity is easily crushed by the pressure applied to the heating resistor. In particular, since the drum sandwiching the printing paper with the heating resistor is arranged along the arrangement direction of the heating resistors, the underglaze layer may break along the arrangement direction of the heating resistors.

Third, the conventional method of providing a cavity at the middle position in the thickness direction of the underglaze layer is to print and dry an evaporative component layer made of a cellulosic resin on the surface of the underglaze lower layer, An underglaze surface layer forming paste made of the same insulating material as the underglaze lower layer is formed on the surface and dried. Further, the insulating material laminated in this way is baked at a temperature of about 1300 ° C. to evaporate the evaporation component layer. Therefore, a complicated process is required to provide the cavity under the heating resistor, and time is required for manufacturing.

The present invention has been made in view of the above-described circumstances, and improves the heat generation efficiency of the heating resistor to reduce power consumption, while improving the strength of the substrate under the heating resistor, while being simple and inexpensive. It is an object of the present invention to provide a heat generating resistive element that can be manufactured in the same manner, a thermal head and a printer using the same.

In order to solve the above problems, the present invention employs the following means.

That is, the present invention includes a substrate, a heat storage layer that is bonded to one surface of the substrate, and a plurality of heating resistors arranged with intervals on a heat storage layer, a plurality of said one surface of said substrate The recess formed in the region facing the heating resistor is closed by the heat storage layer, thereby communicating with each other along the arrangement direction of the plurality of heating resistors between the substrate and the heat storage layer. In addition, a heating resistor element is provided in which a heat insulating cavity that is sealed from the outside is formed.

In the heating resistance element configured as described above, a recess such as a groove is formed in a region facing the heating resistor on one side of the heat storage layer of the substrate, and the opening of the recess is closed by the heat storage layer, thereby In a region facing the heat generating resistor between the heat storage layer and the heat storage layer, a heat insulating cavity that is in communication with each other and sealed to the outside is formed.

The gas layer in the cavity functions as a heat insulating layer that regulates the inflow of heat from the heat storage layer to the substrate.

Since this heating resistance element can be made by the same manufacturing method as the heating resistance element having no cavity, except that the substrate having the recess and the heat storage layer are bonded together, the heating resistance having a conventional gap is formed. Compared with the device, the manufacturing process is simplified and the manufacturing cost is low.

Moreover, in this heat generating resistive element, since the depth of a recessed part becomes the thickness of a heat insulation layer, control of the thickness of a heat insulation layer is easy.

In addition, the shape of the recess may be formed in a groove shape extending over a plurality of heating resistors .
Since the recesses extending over the plurality of heating resistors are communicated with each other, the hollow portions provided for each heating resistor are connected to each other, and each heating element is heated according to the difference in the operating state of each heating resistor. Even if a temperature difference of the resistor occurs, it is possible to prevent an internal pressure difference between the hollow portions. Since the pressure in the cavity affects the heat conduction, the heat generation characteristics of the respective heating resistors can be easily made uniform by connecting the cavity.

In this heating resistor element, the depth of the recess may be 1 μm or more and 100 μm or less.

In this case, the thickness of the gas layer in the cavity is sufficiently secured to be 1 μm or more, and the heat insulation effect by this gas layer is high, so that the power consumption of the heating resistor element can be reduced. Moreover, since the depth of the recess is 100 μm or less, the thickness of the heating resistor element can be suppressed.

Moreover, in the said invention, gas may be enclosed in the cavity part.

In this case, the pressure applied to the heating resistor is supported by the pressure of the gas sealed in the cavity, and the pressure resistance performance can be further improved.

Here, the gas sealed in the cavity is preferably an inert gas.

By doing in this way, deterioration, such as oxidation of a heating resistor, can be prevented and reliability and durability can be improved.

Further, in any one of the above heating resistor elements , the inside of the cavity portion may be decompressed to an atmospheric pressure or lower.

In this case, the fluctuation of the internal pressure in the cavity can be suppressed by a temperature change caused by the operation of the heating resistor.

In the above heating resistor element, the heat storage layer may be made of thin glass having a thickness of 10 μm to 100 μm.

In this case, the heat storage layer is made of thin glass having a thickness of 10 μm or more, and its mechanical strength is sufficiently ensured, so that the reliability is high.

In addition, since the heat storage layer is as thin as 100 μm or less and the heat capacity of the heat storage layer itself is small, in this heating resistor element, the heat generated by the heating resistor is not taken away by the heat storage layer and used for the intended heat treatment. And heat generation efficiency is high.

It is preferable that the thin glass-made heat storage layer and the substrate are bonded at a temperature of 700 ° C. or lower .

In this case, since the joining process is performed at a temperature lower than the softening point of the thin glass constituting the heat storage layer, the shape accuracy of the heat storage layer can be maintained and the reliability is high.

The present invention also provides a thermal head including the heating resistor element having the above configuration.

According to this thermal head, since the heat generating resistor element having high heat generation efficiency and low manufacturing cost is used, low cost is achieved while realizing low power consumption.

The present invention also provides a printer using the thermal head configured as described above.

According to this printer, since the thermal head having high heat generation efficiency and low manufacturing cost is used, low cost is achieved while realizing low power consumption.

The present invention is also a method of manufacturing a heating resistor element having a substrate, a heat storage layer formed on the substrate, and a heating resistor provided on the heat storage layer, the substrate and the heat storage layer. And at least one of them is configured such that a recess is provided on one surface, and a bonding step of bonding the substrate and the heat storage layer in a direction in which the one surface is a bonding surface, and the above on the heat storage layer There is provided a method for manufacturing a heating resistor element comprising a heating resistor forming step of forming the heating resistor in a portion facing a recess.

In this method of manufacturing a heating resistor element, at least one of the substrate and the heat storage layer has a configuration in which a recess is formed on one surface, and the surface on which the recess is formed is connected to the substrate and the heat storage layer. Join in the orientation. Thereby, a cavity is formed in a region where a recess is formed between the substrate and the heat storage layer. The gas layer in the cavity functions as a heat insulating layer that regulates the inflow of heat from the heat storage layer to the substrate.

Further, a heating resistor is formed in a portion facing the recess on the heat storage layer. As a result, a heating resistor element in which a cavity is formed in a portion facing the heating resistor can be obtained.

Since the manufacturing method of this heating resistance element can use the same process as the manufacturing method of the heating resistance element that does not have a cavity, except that the concave portions are formed on the substrate and the heat storage layer and these are bonded together. The manufacturing process can be simplified as compared with the conventional method for manufacturing a heating resistor element having a gap, and the manufacturing cost can be reduced.

Here, the substrate or the heat storage layer may be formed into a shape having a recess in the manufacturing stage, or may be formed by etching, machining, or the like after being formed into a flat plate shape. Since the processing by etching has high processing accuracy, the shape accuracy of the concave portion can be sufficiently increased even when the concave portion is fine. Moreover, the thickness of a heat insulation layer can be adjusted by adjusting the depth of a recessed part.

In addition, the present invention provides an adhesive layer forming step of forming an adhesive layer having a predetermined shape on one surface of the substrate, and adhering a heat storage layer to the one surface of the substrate, and the adhesive between the substrate and the heat storage layer. Production of a heating resistor element comprising: an adhesion step for forming a cavity where no layer is formed; and a heating resistor formation step for forming a heating resistor in a region facing the cavity on the heat storage layer Provide a method.

In this method for manufacturing a heating resistor element, the substrate and the heat storage layer are bonded together via an adhesive layer. An adhesive layer is not provided in a part of the region between the substrate and the heat storage layer, thereby forming a cavity. The gas layer in the cavity functions as a heat insulating layer that regulates the inflow of heat from the heat storage layer to the substrate.

Furthermore, a heating resistor is formed at a portion facing the cavity on the heat storage layer. As a result, a heating resistor element in which a cavity is formed in a portion facing the heating resistor can be obtained.

The manufacturing method of the heating resistor element is the same as the manufacturing method of the heating resistor element having no cavity, except that an adhesive layer having a predetermined pattern is formed between the substrate and the heat storage layer and these layers are bonded together. Since the process can be used, the manufacturing process can be simplified as compared with the conventional method for manufacturing a heating resistor element having a void, and the manufacturing cost can be reduced.

Here, the thickness of the heat insulating layer formed by the cavity can be adjusted by adjusting the thickness of the adhesive layer.

According to the heating resistor element, the thermal head, and the printer according to the present invention, the manufacturing cost can be reduced while realizing low power consumption. In addition, the strength of the heating resistor element can be improved.

Embodiments of the present invention will be described below with reference to the drawings.
[First embodiment]
In this embodiment, an example in which the present invention is applied to a thermal printer is shown.

As shown in FIG. 1, a thermal printer 1 according to this embodiment includes a main body frame 2, a horizontally disposed platen roller 3, and a thermal head 4 (heating resistance element) disposed to face the outer peripheral surface of the platen roller 3. And a paper feed mechanism 6 that feeds the thermal paper 5 between the platen roller 3 and the thermal head 4, and a pressurizing mechanism 7 that presses the thermal head 4 against the thermal paper 5 with a predetermined pressing force.

The thermal head 4 has a plate shape as shown in the plan view of FIG. 2, and as shown in a cross-sectional view of FIG. 3 (a cross-sectional view taken along arrow α-α in FIG. 2), A heat storage layer 12 joined to the heat storage layer 12, a heat generating resistor 13 provided on the heat storage layer 12, and a protective film layer 14 covering the heat storage layer 12 and the heat generating resistor 13 to protect them from wear and corrosion. .

In the present embodiment, the substrate 11 and the heat storage layer 12 are joined by anodic bonding. A plurality of heating resistors 13 are arranged in the thermal head 4 along the longitudinal direction of the platen roller 3.

In the thermal head 4, an insulating substrate such as a glass substrate, a silicon substrate, or an alumina ceramic substrate is used as the substrate 11, as in a general thermal head. A glass substrate having a silicon dioxide content of 50% to 80% is used. As the alumina ceramic substrate, an aluminum oxide content of 95% to 99.5% is used. In the present embodiment, a silicon substrate is used as the substrate 11.

Here, as will be described later, since the heat storage layer 12 is made of thin glass, when a silicon substrate having properties close to the material of the heat storage layer 12 is used as the substrate 11, the thermal head 4 is thermally expanded. Less distortion.

An alumina ceramic substrate is generally used as a substrate for a thermal head, and has a Young's modulus larger than that of a glass or silicon substrate and higher mechanical strength. When various kinds of thin films are formed, distortion due to film stress hardly occurs.

The heat storage layer 12 is made of thin glass having a thickness of 10 μm or more, and has sufficient mechanical strength. Further, the thickness of the heat storage layer 12 is set to 100 μm or less, whereby the thickness of the thermal head 4 is reduced.

The heating resistor 13 includes a heating resistor layer 21 formed in a predetermined pattern on the heat storage layer 12, and an individual electrode 22 and a common electrode 23 provided on the heat storage layer 12 in contact with the heating resistor layer 21. ing.

In this thermal head 4, a recess 26 is formed in a region facing the heating resistor 13 in at least one of the surface of the substrate 11 on the heat storage layer 12 side and the surface of the heat storage layer 12 on the substrate 11 side. Has been. As a result, a cavity 27 is formed in a region facing the heating resistor 13 between the substrate 11 and the heat storage layer 12.

The gas layer in the hollow portion 27 functions as a heat insulating layer that regulates the inflow of heat from the heat storage layer 12 to the substrate 11.

Here, the shape of the recess 26 is arbitrary, and the size thereof may be larger or smaller than the heating resistor 13 as long as it is close to the dimension of the heating resistor 13.

When the size of the concave portion 26 in plan view is larger than the effective heat generation area of the heating resistor 13, the heat insulation performance between the heating resistor 13 and the substrate 11 is increased. On the other hand, when the size of the recess 26 in plan view is made smaller than the effective heat generation area of the heat generating resistor 13, the mechanical strength of the silicon substrate 11 can be improved.

In the present embodiment, the recess 26 is provided on the one surface side of the substrate 11 and has a substantially rectangular shape slightly smaller than the heating resistor 13 in plan view. Further, the depth D of the recess 26 is set to 1 μm or more and 100 μm or less. That is, in this thermal head 4, the thickness of the gas layer in the cavity 27 is sufficiently secured to be 1 μm or more, and the heat insulating effect by this gas layer is high. Further, since the depth of the recess 26 is 100 μm or less, the thickness of the thermal head 4 can be suppressed.

Next, a method for manufacturing the thermal head 4 according to the present embodiment will be described.

First, a recess 26 having a predetermined depth is formed in a region on one surface of the substrate 11 (silicon wafer) where the heating resistor layer 21 is formed (recess forming step).

The recess 26 is created by performing etching or laser processing on one surface of the substrate 11, for example.

When processing the substrate 11 by etching, first, an etching mask having an etching window opened in a region where the recess 26 is provided is formed on one surface of the substrate 11 by sputtering, vacuum deposition, CVD, or other methods. To do. In this state, one surface of the substrate 11 is etched to form a recess 26 having a predetermined depth.

In the present embodiment, a photoresist material is applied to one surface of the substrate 11, and this photoresist material is exposed using a photomask having a predetermined pattern to solidify a portion other than a region where the recess 26 is formed. Thereafter, one surface of the substrate 11 is washed to remove the unsolidified photoresist material, thereby obtaining an etching mask in which an etching window is formed in a region where the recess 26 is formed. In this state, the concave portion 26 having a predetermined depth is obtained by etching one surface of the substrate 11. For this etching process, dry etching such as reactive ion etching (RIE) or plasma etching is used in addition to wet etching using, for example, a tetramethylammonium hydroxide solution or a hydrofluoric acid-based etching solution.

Next, after all the etching mask is removed from one surface of the substrate 11, a thin glass plate having a thickness of 10 μm to 100 μm is bonded to the one surface to obtain the heat storage layer 12 (bonding step).

In this state where the thin glass is bonded to one surface of the substrate 11 to form the heat storage layer 12, an independent cavity 27 is formed between the substrate 11 and the heat storage layer 12 in the region where the recess 26 is formed. It is formed. Here, since the depth D of the recess 26 becomes the thickness of the cavity 27 (the thickness of the heat insulating layer), the thickness of the heat insulating layer can be easily controlled.

It should be noted that the ambient atmosphere gas in the bonding process is sealed in the cavity portion 27. For example, when the bonding process is performed in the atmosphere, the atmosphere is sealed in the cavity 27.

In the present embodiment, the bonding between the substrate 11 and the thin glass is performed using an anodic bonding technique.

Specifically, first, one surface of the thin glass sheet is combined with one surface of the substrate 11, and the substrate 11 and the thin glass sheet are heated from 300 ° C. to 500 ° C. In this state, when a voltage of 500 V to 1 kV is applied between the substrate 11 and the thin glass, a large electrostatic attractive force is generated between the substrate 11 and the thin glass, and these interfaces are chemically bonded and bonded. Is done.

The joining process between the thin glass-made heat storage layer 12 and the substrate 11 is performed at a temperature of 700 ° C. or lower, that is, at a temperature lower than the softening point of the thin glass. Therefore, the thermal head 4 maintains the shape accuracy of the heat storage layer 12. Can be reliable.

Here, a thin glass sheet having a thickness of about 10 μm is difficult to manufacture and handle and is expensive. Therefore, instead of directly bonding such a thin sheet glass to the substrate 11, after bonding the sheet glass having a thickness that can be easily manufactured and handled to the substrate 11, the sheet glass is desired by etching or polishing. You may process so that it may become thickness. In this case, a very thin heat storage layer 12 can be easily and inexpensively formed on one surface of the substrate 11.

In addition, the various etching used for formation of the recessed part 26 as mentioned above can be used for the etching of thin glass. In addition, for polishing the thin glass, for example, CMP (chemical mechanical polishing) used for high-precision polishing of a semiconductor wafer or the like can be used.

On the heat storage layer 12 thus formed, the heating resistor layer 21, the individual electrode 22, the common electrode 23, and the protective film layer 14 are sequentially formed (heating resistor forming step). The order in which the heating resistor layer 21, the individual electrode 22, and the common electrode 23 are formed is arbitrary.

The heating resistor layer 21, the individual electrode 22, the common electrode 23, and the protective film layer 14 can be formed using a method for manufacturing these members in a conventional thermal head.

Specifically, a thin film of a heating resistor material such as a Ta-based or silicide-based film is formed on the heat storage layer 12 by using a thin film forming method such as sputtering, CVD (chemical vapor deposition), or vapor deposition. By forming a thin film of a resistor material using a lift-off method, an etching method, or the like, the heating resistor 13 having a desired shape is formed.

Similarly, a wiring material such as Al, Al-Si, Au, Ag, Cu, and Pg is formed on the heat storage layer 12 by sputtering or vapor deposition, and this film is formed using a lift-off method or an etching method. The wiring material is screen-printed and then fired to form the individual electrodes 22 and the common electrode 23 having desired shapes.

In the present embodiment, two independent individual electrodes 22 are provided for one heating resistor 13, and the common electrode 23 is provided on one individual electrode 22, thereby reducing the wiring resistance value of the common electrode 23. We are trying to reduce it.

After forming the heating resistor layer 21, the individual electrode 22, and the common electrode 23 in this way, a protective film material such as SiO ₂ , Ta ₂ O ₅ , SiAlON, Si ₃ N ₄ , diamond-like carbon, etc. on the heat storage layer 12. Is formed by sputtering, ion plating, CVD, or the like to form the protective film layer 14.

Thereby, the thermal head 4 shown in FIG. 1 is manufactured.

In the thermal head 4 configured as described above, a cavity portion 27 is formed in a region facing the heating resistor 13 between the substrate 11 and the heat storage layer 12, and the gas layer in the cavity portion 27 is configured to store heat. It functions as a heat insulating layer that regulates the inflow of heat from the layer 12 to the substrate 11. In the present embodiment, the depth D of the recess 26 is 1 μm or more, and the thickness of the gas layer in the cavity 27 is 1 μm or more, so that the heat insulating effect by this gas layer is high.

Furthermore, in this thermal head 4, since the heat storage layer 12 is as thin as 100 μm or less and the heat capacity of the heat storage layer 12 itself is small, the heat generated by the heating resistor 13 is effective for printing without being taken away by the heat storage layer 12. Used for

As described above, in the thermal head 4, the heat generated by the heating resistor 13 can be effectively used for printing, so that the heating efficiency of the heating resistor 13 is high.

In addition, since the heat generated by the heating resistor 13 is not easily transmitted to the substrate 11, the temperature of the entire thermal head 4 is unlikely to rise even if print output is continuously performed. For this reason, the thermal printer 1 according to the present embodiment can perform high-quality continuous printing.

Further, the thermal head 4 is the same manufacturing method as the thermal head having no cavity 27 except that a concave portion 26 is formed on one surface of the substrate 11 and a thin glass plate that becomes the heat storage layer 12 is bonded to the one surface. Therefore, the manufacturing process is simplified and the manufacturing cost can be reduced as compared with the conventional thermal head having a gap.

Moreover, in this thermal head 4, since the board | substrate 11 and the thermal storage layer 12 are joined by anodic bonding, the board | substrate 11 and the thermal storage layer 12 can be joined directly, without apply | coating an adhesive agent, and a manufacturing process. Is simplified.

Thus, the thermal head 4 has high heat generation efficiency and low manufacturing cost.

For this reason, the thermal printer 1 using the thermal head 4 is low in cost while realizing low power consumption.

Here, as a reference example, an example in which the concave portion 26 is formed in the substrate 11 has been shown. However, the present invention is not limited to this, and instead of providing the concave portion 26 in the substrate 11, as shown in FIG. A recess 26 may be provided on the surface of the layer 12 facing the one surface of the substrate 11, and the recess 26 may be provided on both the substrate 11 and the heat storage layer 12 so as to face each other.

[Reference example]
The thermal printer shown in this reference example uses the thermal head 31 shown in FIG. 4 in place of the thermal head 4 in the thermal printer 1 shown in the first embodiment.

Hereinafter, members that are the same as or the same as those of the thermal head 4 shown in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

The thermal head 31 is provided with an adhesive layer 32 having a predetermined pattern between the substrate 11 and the heat storage layer 12 instead of providing the recess 26 in the substrate 11 in the thermal head 4 shown in the first embodiment. Here, since the temperature of the heating resistor 13 rises from about 200 ° C. to about 300 ° C. during the operation of the thermal head 31, the adhesive constituting the adhesive layer 32 can withstand the temperature of the heating resistor 13. High heat resistant material is used.

Specifically, the adhesive layer 32 is made of a glass paste mainly composed of silicon dioxide or boron trioxide, or a polymer resin material such as a polyimide resin or an epoxy resin.

Of the region between the substrate 11 and the heat storage layer 12, the region facing the heating resistor 13 is a cavity 27 where the adhesive layer 32 is not formed.

The shape of the hollow portion 27 is arbitrary, and the size thereof may be larger or smaller than the heating resistor 13 as long as it is close to the size of the heating resistor 13.

When the size of the cavity 27 in plan view is larger than the effective heat generation area of the heating resistor 13, the heat insulation performance between the heating resistor 13 and the substrate 11 is increased. On the other hand, when the size of the hollow portion 27 in plan view is made smaller than the effective heat generation area of the heating resistor 13, the mechanical strength of the silicon substrate 11 can be improved.

In this reference example , a substantially rectangular cavity 27 that is slightly smaller than the heating resistor 13 in plan view is formed between the substrate 11 and the heat storage layer 12.

In this reference example , the thickness T of the adhesive layer 32 is set to 1 μm or more and 100 μm or less. That is, in the thermal head 31 according to this reference example , the thickness of the gas layer in the cavity 27 formed between the substrate 11 and the heat storage layer 12 is in the range of 1 μm to 100 μm.

That is, in this thermal head 31, the thickness of the gas layer in the cavity 27 is sufficiently secured to be 1 μm or more, and since the heat insulation effect by this gas layer is high, the power consumption can be reduced. Moreover, since the thickness of the cavity 27 is 100 μm or less, the thickness of the thermal head 31 can be suppressed.

Hereinafter, a method for manufacturing the thermal head 31 will be described.

First, the adhesive described above is applied to one surface of the substrate 11 or the surface of the heat storage layer 12 facing the substrate 11 to form an adhesive layer 32 having a predetermined pattern (adhesive layer forming step).

The adhesive layer 32 is formed on one surface of the substrate 11 by patterning using screen printing or photolithography.

In this reference example , the adhesive layer 32 is formed by patterning using photolithography. Specifically, a mask pattern in which a region for forming the adhesive layer 32 is formed by photolithography is formed on the substrate 11, and after filling the opening with the adhesive, the mask pattern is removed to form a predetermined pattern. An adhesive layer 32 is formed.

Here, in this thermal head 31, since the thickness T of the adhesive layer 32 becomes the thickness of the heat insulating layer, the control of the thickness of the heat insulating layer is easy.

After drying the adhesive layer 32 formed in this manner, the substrate 11 and the heat storage layer 12 are bonded via the adhesive layer 32 (adhesion step). Thereby, the cavity 27 in which the adhesive layer 32 is not formed is formed between the substrate 11 and the heat storage layer 12.

Here, when the said glass paste is used as an adhesive agent, the board | substrate 11 and the thermal storage layer 12 are adhere | attached by performing heat processing. In order to prevent deformation of the heat storage layer 12 during the heat treatment, a glass paste having a low melting point below the softening point (700 ° C.) of the thin glass constituting the heat storage layer 12 should be used. Is preferred.

It should be noted that the ambient atmosphere gas in the bonding process is enclosed in the cavity 27. For example, when the bonding process is performed in the air, the air is enclosed in the cavity 27.

Thereafter, in the same manner as the thermal head manufacturing method shown in the first embodiment, the heating resistor 13 is formed in a region facing the cavity 27 on the heat storage layer 12 (heating resistor forming step).

In the thermal head 31 configured as described above, a region facing the heating resistor 13 between the substrate 11 and the heat storage layer 12 is a cavity 27 where the adhesive layer 32 is not formed, The gas layer in the hollow portion 27 functions as a heat insulating layer that regulates the inflow of heat from the heat storage layer 12 to the substrate 11.

In this thermal head 31, the substrate 11 is a silicon substrate, and the adhesive constituting the adhesive layer 32 is a glass material or a polymer resin material. That is, in the thermal head 31, a material having low thermal conductivity is used as an adhesive, and the amount of heat flowing from the heat storage layer 12 to the substrate 11 through the adhesive layer 32 is small.

For this reason, in this thermal head 31, the heat generated by the heating resistor 13 can be effectively used for printing, and the heating efficiency of the heating resistor 13 is high.

Further, the thermal head 31 is manufactured in the same manner as the thermal head having no cavity 27 except that an adhesive layer 32 having a predetermined pattern is formed between the substrate 11 and the heat storage layer 12 and these are bonded together. Since it can be produced by the method, the manufacturing process is simplified and the manufacturing cost is low as compared with a thermal head having a conventional gap.

In this thermal head 31, since the adhesive layer 32 is formed by patterning using screen printing or photolithography, the shape accuracy of the obtained adhesive layer 32 is high. That is, in the thermal head manufacturing method according to the present embodiment, the cavity 27 can be accurately formed at a desired position, so that the yield of the thermal head 31 is good.

Here, in each of the above-described embodiments, the inside of the cavity 27 provided to face each heating resistor 13 may be decompressed to an atmospheric pressure or lower.

In this case, the heat conduction by the gas in the cavity 27 can be reduced, and the heat insulation effect can be further improved. Further, it is possible to avoid the pressure in the cavity portion 27 in the sealed state from fluctuating according to the temperature change due to the operation of the heating resistor 13. Here, a higher effect can be obtained by making the inside of the cavity 27 into a vacuum state.

Further, a gas in a pressure state higher than the atmospheric pressure may be enclosed in the cavity 27 provided to face each heating resistor 13. By doing in this way, when a force is applied from the outside to the heat generating surface of the heat generating resistor 13 composed of a thin film, the pressure in the cavity 27 opposes this external force and prevents the heat generating surface from being deformed. Alternatively, the effect of restoring the original state after deformation can be obtained.

In this case, it is preferable to use an inert gas such as N ₂ , He, or Ar as the gas sealed in the cavity 27. By doing in this way, even if the gas enclosed in the cavity part 27 permeates | transmits the thermal storage layer 12, and reaches | attains the heat generating resistor 13, the problem that the heat generating resistor 13 oxidizes or a characteristic deterioration can be prevented. The reliability and reproducibility of the thermal head is increased.

Further, as a reference example , the shape of the concave portion 26 formed in the substrate 11 and the cavity portion 27 formed between the substrate 11 and the heat storage layer 12 are arbitrary, and each heating resistor 13 is independently provided. It may be provided, or may be formed in a shape that spans the plurality of heating resistors 13. It should be noted that the number and arrangement of the recesses 26 (or the cavity portions 27) corresponding to the respective heating resistors 13 can be arbitrary.

For example, as in the thermal head 4a shown in FIG. 5, a plurality of concave portions 26 may be provided at positions facing each of the heating resistors 13. In this case, it is possible to reduce the size of each recess 26 while maintaining the sum of the sizes of the recesses 26 corresponding to one heating resistor 13. That is, in the thermal head 4a, the mechanical strength of the substrate 11 can be maintained while maintaining the heat insulating performance by maintaining the size of the heat insulating layer.

Here, in the example shown in FIG. 5, nine concave portions 26 are squarely arranged in the heat generation effective area of the heat generating resistor 13, and the concave portions 26 are opposed to the central portion of the heat generating resistor 13 to be heated most. By providing, high heat insulation performance is obtained.

In the first embodiment, as in the thermal head 4 b shown in FIG. 6, a communication hole 26 a that communicates each recess 26 formed individually for each heating resistor 13 may be provided.

Here, the thermal head 4b shown in FIG. 6 is an example in which a groove-shaped communication hole 26a is formed on the side of the substrate 11 and the heat storage layer 12 where the recess 26 is formed. Moreover, the thermal head 4c shown in FIG. 7 as a reference example is an example in which a groove-shaped communication hole 26a is formed on the side of the substrate 11 and the heat storage layer 12 where the concave portion 26 is not formed.

When these structures are adopted, even if the temperature state is different for each heating resistor 13, the pressure state in the recesses 26 for all the heating resistors 13 can be made constant. The communication hole 26 a can be created using the same method as that for the recess 26. Further, the communication hole 26a can be easily created by performing groove processing with the dicer on the substrate 11 and the heat storage layer 12.

Further, as a reference example , the recess 26 may be opened to the atmosphere like the thermal head 4d shown in FIG. 8 or the thermal head 4e shown in FIG.

Here, the thermal head 4d shown in FIG. 8 is obtained by providing a groove-like communication hole 26a from an arbitrary recess 26 to the end of the thermal head in the thermal head 4b shown in FIG. A thermal head 4e shown in FIG. 9 is the same as the thermal head 4c shown in FIG. 7, except that the end of the communication hole 26a extends to the outer surface of the end of the thermal head.

When these configurations are employed, the internal pressure in the cavity 27 provided in each heating resistor 13 can be maintained at a uniform atmospheric pressure. Since the pressure in the cavity 8 affects heat conduction, the heat generation characteristics of the respective heating resistors 13 can be made uniform by opening the cavity 27 to the atmosphere.

In each of the above-described embodiments, the heating resistor layer 21, the individual electrode 22, and the common electrode 23 of the thermal head have been shown to be formed by a thin film process. However, the heating resistor layer is not limited to this. 21, the individual electrode 22, and the common electrode 23 may be formed by a thick film process using resinate gold or ruthenium oxide, respectively.

Further, the present invention can be applied to all types of thermal heads regardless of the structure of the full glaze type, the partial glaze type, the near edge type, or the like.

In addition, the present invention uses a thermal paper called a direct thermal type, uses a thermal transfer ribbon of a melt type or a sublimation type, and recently, once printed on a film-like medium and then reprinted on a hard medium. It can be applied to all types of thermal printers such as those to be transferred.

In addition to the thermal heads 4 and 31 shown in the above embodiments, the present invention fixes a thermal erasing head having substantially the same structure as the thermal heads 4 and 31 and a printer that requires thermal fixing. The present invention can be applied to electronic components having other film-like heating resistor elements such as heaters and thin film heating resistor elements of optical waveguide type optical components. In addition, there is a possibility that it can be applied to thermal and bubble ink jet heads.

1 is a longitudinal sectional view illustrating a configuration of a thermal printer according to a first embodiment of the present invention. It is a top view which shows the structure of the thermal head which concerns on 1st embodiment of this invention. FIG. 3 is a cross-sectional view taken along the line aa in FIG. 2. It is a longitudinal cross-sectional view which shows the structure of the thermal head which concerns on the reference example of this invention. It is a top view which shows the other example of a thermal head which concerns on 1st embodiment of this invention. It is a top view which shows the other example of a thermal head which concerns on 1st embodiment of this invention. It is a top view which shows the other example of a thermal head which concerns on the reference example of this invention. It is a top view which shows the other example of a thermal head which concerns on the reference example of this invention. It is a top view which shows the other example of a thermal head which concerns on the reference example of this invention.

Explanation of symbols

1 Thermal printer 4, 4a-4e, 31 Thermal head (heating resistance element)
11 substrates
12 heat storage layers
21 Heating resistor layer 26 Recess 27 Cavity 32 Adhesive layer

Claims

A substrate,
A heat storage layer bonded to one surface of the substrate;
A plurality of heating resistors arranged at intervals on the heat storage layer;
An array of a plurality of heating resistors is provided between the substrate and the heat storage layer by closing recesses formed in a region facing the plurality of heating resistors on the one surface of the substrate with the heat storage layer. A heat generating resistive element in which a heat insulating cavity is formed which communicates with each other along a direction and is sealed from the outside .
The heating resistance element according to claim 1, wherein the depth of the recess is 1 μm or more and 100 μm or less.
The heating resistance element according to claim 1, wherein a gas is sealed in the hollow portion .
The heating resistor element according to claim 3 , wherein the gas is an inert gas.
The heating resistance element according to claim 1, wherein the inside of the hollow portion is depressurized to an atmospheric pressure or lower.
The heating resistance element according to any one of claims 1 to 5 , wherein the heat storage layer is made of a thin glass sheet having a thickness in a range of 10 µm to 100 µm.
The heating resistor element according to any one of claims 1 to 6, wherein the substrate and the heat storage layer are bonded at a temperature of 700 ° C or lower .
A thermal head comprising the heating resistor element according to claim 1 .
A printer using the thermal head according to claim 8 .