JP4297824B2 - Thermal head and manufacturing method thereof - Google Patents

Description

  The present invention relates to a thermal head mounted on various business and consumer printer devices, a thermal head corresponding to a printing function associated with a personal computer, a digital camera, and the like, and a manufacturing method thereof.

  There are thermal heads for batch heating that are used for batch erasing with rewrite media and overcoating for transfer to media. The thermal head for batch heating is not intended for printing as in the so-called multi-dot type, but can be used to erase the information printed on the printed material as described above depending on the required temperature, It is used for coating.

  The conventional structure of this thermal head is, for example, as shown in FIGS. 3 and 4, a ceramic substrate b2 disposed on a heat sink b1 formed in a substantially rectangular parallelepiped shape, and a belt-like shape on the ceramic substrate b2. A thick film heating element b3 applied to the electrode, an electrode b4 connected to both longitudinal ends of the heating element for applying power to the heating element b3, and a protective layer b5 covering the heating element b3. It becomes. The short direction perpendicular to the longitudinal direction of the heating element is the sub-scanning direction, which is the medium transport direction (or head moving direction).

  Also, as a main configuration of the conventional thermal head manufacturing method, generally, a heating element b3 is printed on the ceramic substrate b2 in a thick film, an electrode b4 is connected, and the surface of the heating element b3 is heated. The protective layer b5 is formed by softening glass or the like, and a polishing process is performed to ensure the required flatness.

  As another conventional thermal head structure, for example, in a thermal head having a plurality of heating resistor dot patterns on a straight line (different from the above-described batch heating thermal head), the heating resistor dot pattern is a straight line. These heating resistor patterns are connected to the lead electrode conductors. With the above configuration, there is a thermal head in which valleys are less likely to occur in the temperature distribution between the arrayed heating resistor patterns, and as a result, a uniform heat pulse can be applied during head scanning (see Patent Document 1). ).

  Further, a heating resistor provided on the surface of the glaze layer provided on the plate-like substrate, an electrode group electrically connected to the heating resistor, and a protective layer covering at least the heating resistor is provided. The body has a first heating resistor dedicated to thermal recording and a second heating resistor dedicated to thermal erasure. There is a thermal head in which a sufficient thermal recording function and thermal erasing function can be obtained by the above-described configuration and can be provided at a small size and at low cost (see Patent Document 2).

JP-A-6-286185 (second page, FIG. 1) JP-A-5-254168 (2nd page, FIG. 1)

The conventional thermal head described above has the following problems.
First, the above-described conventional thermal head has a temperature gradient because the electrodes for applying power to the heating element are connected to both ends in the longitudinal direction of the heating element, that is, the temperature distribution of the heating element. For example, when information printed on a printing material is erased, there is a problem that it cannot be completely erased due to the generated temperature unevenness.

  This problem is considered to be solved at first glance by the prior art exemplified in Patent Document 1 described above, however, the shape of the heating element has to be complicated to make the temperature distribution uniform, and the manufacturing process is complicated. Increase in production cost and production cost is inevitable, and it is difficult to maintain the quality of the finished product in a stable manner.

  Further, as in the prior art exemplified in the above-mentioned Patent Document 2 and the like, there are electrodes and electrode routing patterns at both ends in the head length direction. Since heating is performed only by heat conduction, thermal responsiveness at both ends is poor. In addition, in order to obtain an effective heat generation width in the head width direction, a chip size larger than the media width is necessary, and it is difficult to reduce the outer shape of the head, and as a result, the apparatus cannot be made compact.

  In particular, when manufacturing a chip mounted with a heating element on a large substrate, it is necessary to set an electrode extraction part in the chip length direction, so individual silk-printed plates or photomasks corresponding to the chip length in advance. Etc. are required, resulting in an increase in manufacturing costs.

  In addition, since the conventional heating element employs thick film printing, the surface roughness is poor, and a protective layer having a sufficient thickness (generally 100 to 1000 μm) is required to ensure the surface property. For this reason, an excessive heat storage phenomenon occurs between the heating element and the medium, resulting in poor responsiveness from the application of power to the transfer of heat to the medium and the transfer of effective heat to the surface of the protective layer. .

  Furthermore, in order to cope with hard card media and the like, it is necessary to polish the surface of the protective layer to ensure a flat surface, but the manufacturing process is very troublesome and complicated in order to ensure accuracy.

  In addition, the base ceramic substrate is inclined on the media transfer port and outlet side so that the media can be smoothly transported in both directions, but the interface between the ceramic processing surface and the protective layer is discontinuous. In addition, when the medium is transported, there is a case where the introduction to the effective heating element surface is not smoothly performed.

  Therefore, the present invention aims to provide a thermal head having a uniform temperature distribution of the heating element and excellent thermal response, and a method for manufacturing the thermal head, and further, eliminating a complicated manufacturing process such as a polishing process, and yield. It is an object of the present invention to provide a thermal head and a method for manufacturing the same.

In order to solve the above problems, the thermal head and the manufacturing method thereof according to the present invention employ the following technical means.
That is, the thermal head of the present invention has a single-dot strip shape on a glaze substrate composed of an insulating substrate provided on a substantially rectangular parallelepiped heat sink and a glaze layer formed on the substrate. A heating head having a structure provided with a heating element and an electrode for applying electric power to the heating element, wherein the electrodes are substantially the entire area of both ends of the heating element in the medium conveying direction. A second electrode connected to the heating element over the entire area, connected to the second electrode over substantially the entire area of both ends of the second electrode in the media transport direction, and from the substrate to the side of the heat sink And a first electrode formed of a flexible substrate.
In the thermal head of the present invention, in the glaze substrate, the substrate has an upper surface formed in a convex shape over a direction orthogonal to the media transport direction of the heat dissipation plate, and the glaze layer is formed on the substrate. It is a thin film formed on the top of the convex upper surface.
In the thermal head of the present invention, the convex step is less than 1.0 millimeter.
In the thermal head of the present invention, the width of the convex top is 1.5 mm or more.
In the thermal head of the present invention, the terminal portion of the first electrode is in contact with a base portion that is a rising base end of the top surface of the convex surface.
In the thermal head of the present invention, the thickness of the glaze layer is in the range of 20 to 200 micrometers.
The thermal head of the present invention includes a protective layer that covers the second electrode and the heating element.
In the thermal head of the present invention, the protective layer is formed as a thin film.
In the thermal head of the present invention, the heating element is formed as a thin film.
In the thermal head of the present invention, the second electrode is formed as a thin film.
In the thermal head of the present invention, the glaze layer is formed by softening and baking glass.
The thermal head according to the present invention is characterized in that the glaze substrate is formed in an inclined surface with a required angle so that the width gradually becomes narrower toward the convex top, and the protective layer is inclined. .
The manufacturing method of the thermal head of the present invention is a manufacturing method of a thermal head for batch heating, and an upper surface is convex on a substantially rectangular parallelepiped heat dissipation plate in a direction orthogonal to the medium conveying direction of the heat dissipation plate. Forming a substrate having insulating properties, forming a glaze layer as a thin film on the convex top, forming a heating element as a single-dot thin film on the upper surface of the glaze layer, and forming the convex upper surface Formed so that the terminal end of the first electrode made of a flexible substrate is in contact with the base that is the rising base end of the top, and electrically connects the terminal end of the first electrode and the end of the heating element The second electrode is formed as a thin film, and the protective layer is formed as a thin film so as to cover the second electrode and the heating element.
The manufacturing method of the thermal head of the present invention is a manufacturing method of a thermal head for batch heating, and an upper surface is convex on a substantially rectangular parallelepiped heat dissipation plate in a direction orthogonal to the medium conveying direction of the heat dissipation plate. An insulating substrate is formed on the convex top, and a glaze layer as a thin film is formed on the convex top by softening and baking glass, and a heating element as a single dot thin film is formed on the upper surface of the glaze layer. And a terminal portion of the first electrode formed of a flexible substrate is brought into contact with a base portion that is a rising base end of the top surface of the convex surface, and the terminal portion of the first electrode and the end of the heating element are formed. The second electrode is formed as a thin film so as to be electrically connected to the portion, and the protective layer is formed as a thin film so as to cover the second electrode and the heating element.
In the method for manufacturing a thermal head according to the present invention, the thickness of the glaze layer is in the range of 20 to 200 μm.
In the thermal head manufacturing method of the present invention, the upper surface of the glaze substrate composed of the insulating substrate and the glaze layer is inclined at a required angle so that the width gradually decreases toward the convex top. It is characterized by forming.

According to the present invention, it is possible to obtain a thermal head for batch heating having a uniform temperature distribution of a heating element and excellent thermal responsiveness while eliminating a complicated manufacturing process such as a polishing process.

  Next, a thermal head according to this embodiment will be described with reference to the accompanying drawings. In the figure, symbol A indicates a thermal head.

  As shown in FIG. 1, the thermal head A according to the present embodiment includes a ceramic substrate (insulating substrate) 1, a glaze layer 2, a heating element 3, an electrode 4, and a protective layer 5. Prepare.

  The ceramic substrate (insulating substrate) 1 is made of ceramics such as alumina, and is formed in a convex shape inclined at a required angle so that the upper surface gradually becomes narrower toward the top portion 1a along the longitudinal direction. And disposed on the heat sink 6 made of an aluminum material or the like formed in a substantially rectangular parallelepiped shape. The ceramic substrate 1 and the later-described glaze layer 2 constitute a glaze substrate.

  The upper surface formed in this convex shape preferably has a level difference of less than about 1.0 millimeter. This is because the step h between the first electrode 41, which will be described later, and the top of the protective layer 5, which is originally formed as a thin film, should be secured as large as possible in order to smoothly disperse the media W when it is transported. However, if the step is approximately 1.0 mm or more, however, the process becomes complicated, for example, pattern formation in the thin film process is divided and exposed on the top 1a side and the bottom side.

  Further, the width of the top portion 1a (short direction) is preferably a required width of at least 1.5 millimeters. In the first place, the erasing characteristic of the medium W such as a rewrite card needs to be kept at a different temperature range for a long time as compared with the time of printing, and gradually cooled, but the width of the top portion 1a is 1.5 mm. If it is less than the above, at a general card conveyance speed (20 to 60 mm / s) at the time of erasure, the contact time with the conveyed medium W cannot be ensured, and sufficient erasure quality cannot be ensured. Further, if the length of the top portion 1a is less than 1.5 millimeters, the top portion curvature becomes small, and the contact with the medium W becomes a state close to line contact from surface contact, and sufficient erasing quality cannot be ensured similarly to the above. Because.

  The glaze layer 2 is formed by softening and firing glass with a thickness of 20 to 200 micrometers on the convex top surface 1 a of the ceramic substrate 1. The reason why the thickness dh of the glaze layer 2 is set to 20 to 200 micrometers is that, as a specific manufacturing process, heat-resistant glass is printed and softened on the convex top portion 1a of the ceramic substrate 1, This is because high-precision flatness can be secured by the surface tension of the glass at that time. The glaze layer 2 may be formed as a thin film.

If it is less than 20 micrometers, it will be affected by the roughness of the convex top surface 1a of the ceramic substrate 1, and it will be difficult to maintain high-precision flatness by crystallization of glaze glass. However, if the convex top surface 1a of the ceramic substrate 1 is finished with high precision by polishing, the glaze layer 2 can also ensure high precision flatness as a result. However, this polishing process is very difficult. It is extremely preferable to eliminate the polishing process because it has to be carried out in a complicated procedure, leading to a decrease in yield and rebounding to production costs.
Further, if the thickness dh of the glaze layer 2 exceeds 200 micrometers, the temperature control becomes difficult due to heat storage or the like, causing a problem in thermal response, which is not suitable when the medium W is conveyed at high speed. End up.

  The heating element 3 is formed in a single dot band shape by a thin film resistor such as polysilicon, for example, and a thin film is formed on the upper surface of the glaze layer 2.

The electrode 4 includes a first electrode 41 and a second electrode 42.
The first electrode 41 is a flexible substrate having a required width provided with electrode terminals 43. The first electrode 41 is disposed on the bottom surface of the heat dissipation plate 6 so that the electrode terminals 43 are positioned, and between the heat dissipation plate 6 and the ceramic substrate 1. The end portion is brought into contact with a base portion which is a rising base end of the convex top surface portion 1a of the ceramic substrate 1 so as to be in close contact with the side surface in the longitudinal direction.

  The second electrode 42 is a conductive member, and is a thin film so that the terminal portion of the first electrode 41 and the end portion in the longitudinal direction of the heating element 3 are electrically connected over substantially the entire end portion. Is formed. In addition, this 1st electrode 41 and the 2nd electrode 42 are comprised by the pair provided so that it might oppose.

  The protective layer 5 is formed in a thin film so as to cover the second electrode 42 and the heating element 3, and the ceramic substrate 1 is inclined at a required angle so that the width gradually decreases toward the convex top 1a. Since it is formed in a planar shape, the protective layer 5 formed as a thin film is inclined along it.

Next, a method for manufacturing the thermal head A according to the above-described embodiment will be described.
First, the radiator plate 6 is formed in a substantially rectangular parallelepiped shape, and the ceramic substrate 1 having an upper surface formed in a convex shape over the longitudinal direction of the radiator plate 6 is disposed on the radiator plate 6. As described above, the convex upper surface is inclined at a required angle so as to gradually become narrower toward the top portion 1a.
And it forms so that the termination | terminus part of the 1st electrode 41 may contact | abut to the base which is a standup | rising base end of the convex upper surface top part 1a.

  Next, the glaze layer 2 is formed by softening and baking the glass on the convex top portion 1a, and a single dot heating element 3 is formed on the top surface of the glaze layer 2 using a thin film deposition apparatus. The second electrode 42 is formed in a thin film so as to electrically connect the terminal portion 41 and the end of the heating element 3, and the protective layer 5 is further provided so as to cover the second electrode 42 and the heating element 3. A thin film is formed. The glaze layer 2 may also be formed as a thin film.

  The thermal head A according to the present embodiment configured as described above is built in a thermal printing / erasing device or the like. At the time of use, the heating element 3 is applied with electric power to increase the required temperature, and a rewritable medium W such as a PET rewritable card printed by a so-called multi-dot thermal head is moved in the conveying direction of the heating element 3. It is transported and the printed information is erased.

As described above, the thermal head A according to the present embodiment connects the second electrode 42 over substantially the entire area of both ends in the transport direction of the heating element 3, and the second electrode 42, the protective layer 5, and the glaze. By forming the layer 2 and the heating element 3 as a thin film, the thermal head A has a uniform temperature distribution of the heating element 3 and excellent thermal responsiveness while eliminating a complicated manufacturing process such as a polishing process. That is, since the electrode portions that are electrically connected to the heating element are provided at both ends in the conveying direction of the heating element to reduce the distance between the electrode parts, the temperature distribution in the length direction of the heating element is reduced. It can be made uniform. In addition, since there is no electrode and a drawing pattern from the electrode at both ends in the head length direction, the end can be heated uniformly and with good responsiveness, and the outer size can be made compact. Also, in the case where the pre-process is manufactured with a large wafer and this is cut, there is no need for electrode parts and electrode routing patterns at both ends in the longitudinal direction of the heating element. The length of the heating element is arbitrarily set from the wafer created by the above, and can be appropriately adjusted to a desired length by cutting it. Further, by forming a glaze layer on the convex top surface of the glaze substrate and disposing a heating element thereon, bi-directional transport with hard media or the like, so-called straight path, becomes possible. In addition, by using a protective film using a thin film, a thermal head having a very excellent thermal response can be provided. In addition to the protective layer, the glaze layer, the heating element, and the second electrode are also formed into a thin film, so that the heat conduction efficiency to the medium can be improved and the size and weight can be reduced. In addition to the protective layer, the heating element and the second electrode are also formed into a thin film, and the glaze layer is formed by softening and baking the glass, improving the heat conduction efficiency to the media and reducing the size and weight. Can be achieved. In addition, by setting the thickness of the glaze layer to 20 to 200 micrometers, it is possible to easily ensure the flatness of the sliding surface between the heat storage function and the media on the protective film. Even if the surface of the insulating substrate, for example, the ceramic substrate has a roughness that is insufficient for the media sliding surface, the glaze layer is formed by the surface tension of the glaze layer when the glass is softened and fired. Since the upper surface can naturally ensure highly accurate flatness, the yield can be improved while eliminating complicated manufacturing processes such as a polishing process. In addition, the second electrode that is electrically connected to the heating element is formed at both ends of the heating element in the conveying direction (short direction), and the protective film, the heating element, and the second electrode are formed into a thin film. The distance between the electrode portions is reduced, and therefore a thermal head excellent in thermal responsiveness with a uniform temperature distribution in the length direction of the heating element can be manufactured. In addition, a glaze layer is formed on a convex top surface of the glaze substrate by forming a thin film or softening and baking glass, and a heating element is disposed on the glaze layer. A thermal head capable of a straight pass can be manufactured.

  The thermal head according to this embodiment has been described above. However, the above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto, and various modifications are made. Is possible.

It is the top view which a part of thermal head concerning this embodiment cut away. It is (X)-(X) sectional drawing in FIG. It is a front view of the conventional thermal head. It is a right view of the conventional thermal head.

Explanation of symbols

A thermal head 1 ceramic substrate 1a top 2 glaze layer 3 heating element 4 electrode 41 first electrode 42 second electrode 43 electrode terminal 5 protective layer 6 heat sink dh thickness of glaze layer h step between first electrode and top of protective layer W Media

Claims (16)

On a glaze substrate composed of an insulating substrate provided on a substantially rectangular heat sink and a glaze layer formed on the substrate, a single-dot belt-shaped heating element, and the heating element A thermal head for batch heating comprising a structure provided with an electrode for applying electric power,
The electrode is
A second electrode connected to the heating element over substantially the entire area of both ends of the heating element in the medium conveying direction;
A first electrode that is connected to the second electrode over substantially the entire area of both ends of the second electrode in the medium conveyance direction, and that is disposed from the substrate to the bottom surface of the heat sink, and is configured by a flexible substrate; With
Thermal head characterized by that. In the glaze substrate,
The substrate has a top surface formed in a convex shape over a direction orthogonal to the media transport direction of the heat sink,
The thermal head according to claim 1, wherein the glaze layer is a thin film formed on a top of the convex upper surface of the substrate. The thermal head according to claim 2, wherein the convex step is less than 1.0 millimeter. 4. The thermal head according to claim 2, wherein a width of the convex top is 1.5 millimeters or more. 5. The thermal head according to claim 2, wherein the terminal portion of the first electrode is in contact with a base portion that is a rising base end of the top portion of the convex upper surface. The thermal head according to any one of claims 2 to 5, wherein the thickness of the glaze layer is in a range of 20 to 200 micrometers. The thermal head according to any one of claims 1 to 6, further comprising a protective layer that covers the second electrode and the heating element. A thermal head according to claim 7, wherein the protective layer being formed as a thin film. The thermal head according to any one of claims 1 to 8, wherein the heating element is formed as a thin film. The thermal head according to any one of claims 1 to 9, wherein the second electrode is formed as a thin film. The glaze layer has a thermal head according to any one of claims 1 to 10, characterized in that it is formed by softening and baking the glass. The glazed substrate, said convex towards the top is formed to the required angle inclined surface shaped so gradually the width becomes narrow, claim from claim 1, wherein the protective layer is characterized by being inclined 11 The thermal head according to any one of the above. On the substantially rectangular parallelepiped heat radiating plate, an insulating substrate having an upper surface formed in a convex shape over a direction orthogonal to the medium conveying direction of the heat radiating plate is formed,
Forming a glaze layer as a thin film on the convex top,
Forming a heating element that is a single-dot thin film on the upper surface of the glaze layer;
Forming the base portion which is the rising base end of the top surface of the convex shape so as to contact the terminal portion of the first electrode formed of a flexible substrate ,
Forming a second electrode in a thin film so as to electrically connect the terminal end of the first electrode and the end of the heating element;
Forming a thin protective layer so as to cover the second electrode and the heating element;
A method of manufacturing a thermal head for batch heating , characterized by comprising: On the substantially rectangular parallelepiped heat radiating plate, an insulating substrate having an upper surface formed in a convex shape over a direction orthogonal to the medium conveying direction of the heat radiating plate is formed,
Forming a glaze layer as a thin film on the convex top by softening and baking glass,
Forming a heating element that is a single-dot thin film on the upper surface of the glaze layer;
Forming the base portion which is the rising base end of the top surface of the convex shape so as to contact the terminal portion of the first electrode formed of a flexible substrate ,
Forming a second electrode in a thin film so as to electrically connect the terminal end of the first electrode and the end of the heating element;
Forming a thin protective layer so as to cover the second electrode and the heating element;
A method of manufacturing a thermal head for batch heating , characterized by comprising:   15. The method of manufacturing a thermal head according to claim 13, wherein the thickness of the glaze layer is in the range of 20 to 200 [mu] m. Claims, characterized in that to form the insulating substrate having an upper surface of the glaze substrate composed of said glaze layer, and required angle inclined such that progressively narrow towards the convex top portion The method for manufacturing a thermal head according to any one of claims 13 to 15 .

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