JP2001277570A - Thermal head and method of manufacturing the head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent adverse effect of accumulated heat by enhancing the heat dissipation performance of a thermal head. SOLUTION: A heating element is covered, on the vicinity thereof, with a protective film 216 covering a part of the first plane 208 of an elongated planar heat resistant substrate 100, the end face 202 of the elongated planar heat resistant substrate 100, and a part of the second plane 212 of the elongated planar heat resistant substrate 100. The first and second planes 208, 212 exposed from the protective film 216 are insulated electrically by a mesh-like insulation film 120 and a heat dissipater 230 for dissipating heat generated from a heater 110 is fixed to the first or second plane 208, 212 through the insulation film 120 and a fluid heat transmission substance 220 spreading into the insulation film 120.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a thermal head having high heat radiation efficiency and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a sublimation printer or a thermal printer forms an image using a thermal head. A conventionally used thermal head has the following structure.

[0003] For example, a thermal head disclosed in Japanese Utility Model Publication No. 6-53151 is configured as shown in FIGS. FIG. 8 is an exploded perspective view of a conventional thermal head, and FIG. 9 is a sectional view taken along line AA of FIG. FIG. 10 is an exploded perspective view of another conventional thermal head, and FIG. 11 is a sectional view taken along line BB of FIG. Hereinafter, these conventional thermal heads will be described.

As shown in FIGS. 8 and 9, a plurality of heating elements are arranged in the longitudinal direction on the end face side of the surface of the thermal head substrate 800, and a heating element 810 is formed. On the surface of the thermal head substrate 800, individual electrodes 813 for individually connecting a plurality of heating elements of the heating element 810 are formed. Also, on the back surface of the thermal head substrate 800, avoiding the regions 820 at both ends thereof,
A common electrode 816 for connecting all of the plurality of heating elements of the heating element 810 in common is formed.

[0005] Each heating element selectively generates heat when an image is formed on transfer paper. Therefore, in order to lower the temperature of the thermal head substrate 800, a heat sink 830 is attached to the back surface of the thermal head substrate 800. The heat sink 830 has projections 840 and 850 for attaching the thermal head substrate 800 at both ends. The protrusions 840 and 850 are formed in regions 820 at both ends of the thermal head substrate 800 (regions where the common electrode 816 is not formed).
And the thermal head substrate 800 and the heat sink 830 are integrated.

[0006] When integrated as described above, a gap is formed in a region excluding regions at both ends of the thermal head substrate 800 and the heat radiating plate 830. If this gap is present, the heat dissipation of the thermal head substrate 800 is adversely affected (heat dissipation is reduced), so the silicone resin 860 having good thermal conductivity and excellent electrical insulation is filled in this gap. are doing.

FIGS. 10 and 11 show improvements of the thermal head shown in FIGS. 8 and 9. FIG. The thermal head is provided with protrusions 840, 850 of a heat sink 830.
In the area excluding the above, the cylindrical protrusions 1000 for supporting the thermal head substrate 800 are evenly provided on the longitudinal center line of the heat radiating plate 830. Touching circular part 10
10 is different from the thermal head shown in FIGS. 8 and 9 in that the common electrode 816 is not formed. Other structures are exactly the same.

The cylindrical protrusion 1000 is provided to prevent the thermal head substrate 800 from bending when subjected to an external force, and the diameter of the protrusion 1000 is in contact with the protrusion 1000. It is formed smaller than the diameter of the circular portion 1010.

[0009]

However, in the conventional thermal head as described above, the thermal head substrate 800 and the heat radiating plate 83 are interposed via the silicone resin 860.
0 is integrated, the heat radiation efficiency and the uniformity of heat radiation are not very good.
The amount of heat radiation tends to be insufficient with respect to the amount of heat generated, and there is a concern that a problem of deteriorating image quality may occur.

That is, in the above-described conventional thermal head, since both ends of the thermal head substrate 800 are joined to the heat radiating plate 830, the thermal head substrate 800 and the heat radiating plate 83 are inevitably considered in consideration of bending of the thermal head.
The gap at the center with zero must be made larger. Therefore, the thickness of the silicone-based resin 860 is also inevitably increased, and naturally, the heat radiation efficiency is reduced. Further, in the thermal head in which the columnar protrusions 1000 are formed, heat is radiated from the thermal head substrate 800 via the protrusions 1000 or the silicone resin 860, and thus the heat radiation of the thermal head substrate 800 is locally different. As a result, the heating element 810 becomes uneven in temperature. This temperature unevenness appears as band-like unevenness in the sub-scanning direction of the transfer paper during printing. To solve this, countless protrusions 100
0 may be provided on the heat radiating plate 830, but since the common electrode 816 needs to be formed on the back surface of the thermal head substrate 800, it is not possible to provide innumerable protrusions 1000.

The occurrence of such a problem is of particular concern in a sublimation type printer which requires a higher printing speed or uses a multi-time ribbon. Sublimation type printers generate more heat per unit time than other types of printers, and are easier to store heat.
This is because heat radiation tends to be insufficient.

When the heat radiation becomes insufficient, the temperature of the thermal head becomes difficult to decrease as a whole. Therefore, after printing a high-density image or printing a high-density character in a single sheet, the tail remains like an afterimage. When printing a relatively high-density uniform image, the printing density may increase as printing progresses (these phenomena are called tailing phenomena). Further, when a plurality of sheets are printed, a phenomenon in which the print density gradually increases appears. Such a phenomenon is because heat is accumulated in the thermal head during printing, and it is difficult to control for printing at a desired density.

In order to cope with the occurrence of these phenomena due to heat storage, a printer using a conventional thermal head has
Perform uniform correction, startup correction, fall correction, etc.
In the control during printing, power supply to each heating element is controlled so that the overall temperature fluctuation of the thermal head is minimized.

By the way, the temperature rise of the thermal head is as follows.
The thermal conductivity of the entire thermal head has a great influence.
Usually, cells used as heat-resistant substrates for thermal heads
The thermal conductivity of a lamic substrate is 60 × 10^-3cal
/ Cm · sec · ° C, from which heat transfer takes place
50 × 10 protective film^-3cal / cm · sec · ° C, flow
Heat transfer material (eg, heat conductive grease, heat conductive contact)
Adhesive) 1-2 × 10 ^-3cal / cm · sec · ° C, keep
0.5 × 10^-3cal / cm · sec · ° C, heat radiation
Vessel (for example, aluminum) is 486 × 10^-3cal /
cm · sec · ° C. As you can see from these figures
In addition, the heat transfer coefficient of the protective layer is extremely small compared to other members.
It is clear that the protective layer is a factor
Call

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional thermal head.
It is an object of the present invention to provide a thermal head that has a structure that can utilize the plane near the second plane or the vicinity of the second plane as a heat transfer path, improves the heat radiation of the thermal head, and can prevent the adverse effect of heat storage, and a method of manufacturing the same.

[0016]

[MEANS FOR SOLVING THE PROBLEMS] To solve the above-mentioned problems,
In order to achieve the object, a thermal head according to the first aspect of the present invention is configured such that a heating element is formed by arranging a plurality of heating elements in a longitudinal direction of an end face of a long plate-shaped heat-resistant substrate, A first plane on which a control element for selectively controlling the plurality of heating elements and supplying power to the conductive substrate is provided, and a second plane on which an electrode common to the plurality of heating elements is formed. The vicinity of the heating element is covered with a protective film that is formed and covers a part of the first plane, an end surface of the long plate-shaped heat resistant substrate, and a part of the second plane, and is exposed from the protective film. The first plane and the second plane are electrically insulated by a mesh-shaped insulating film;
A radiator for radiating heat generated from the heating element is attached to the first plane or the second plane via the insulating film and a fluid heat transfer material that has entered the insulating film. It is characterized by being.

According to the first aspect of the present invention, the first
, The end face of the long plate-shaped heat-resistant substrate, and a protective film covering a part of the second plane, respectively, and then the first plane and the second plane exposed from the protective film. Since it is covered with a mesh-shaped insulating film for electrical insulation and a radiator is attached via the insulating film and a fluid heat transfer material that has entered the insulating film, a long plate-like heat resistance is provided. The heat transfer between the substrate and the radiator becomes better, the heat radiation efficiency of the long plate-shaped heat-resistant substrate is improved, and the radiator radiates the heat energy generated during operation of the heating element evenly and efficiently. become able to.

Therefore, for example, even in a sublimation type high-speed printer or a sublimation printer using a multi-time ribbon, the heat storage in the vicinity of the heating element can be reduced, and the above-mentioned "tailing phenomenon" can be avoided. And the image quality is improved. Further, even when printing a plurality of sheets, it is possible to suppress a rise in temperature near the heating element, so that high-quality printing can be performed. That is, if the printing speed is the same, higher quality printing can be performed than the conventional thermal head. In addition, if printing is performed at the same quality as a conventional thermal head, the printing speed can be increased.

According to a second aspect of the present invention, there is provided a thermal head according to the first aspect, wherein an area of an open area of the mesh-like insulating film is a region where the insulating film is formed. 30-90% of the area of
It is characterized by being.

According to the second aspect of the present invention, the area of the open area of the insulating film formed in a mesh shape is 30 to 90% of the area of the region where the insulating film is formed. Heat transfer and sufficient insulation can be ensured (especially at 90%).

According to a third aspect of the present invention, in the thermal head, a heating element is formed by arranging a plurality of heating elements in the longitudinal direction of the end surface of the long plate-shaped heat-resistant substrate. A first plane on which a control element for selectively controlling the plurality of heating elements and supplying power is provided, and a second plane on which an electrode common to the plurality of heating elements is formed, The vicinity of the heating element is covered with a protective film that covers a part of the first plane, an end surface of the long plate-shaped heat-resistant substrate, and a part of the second plane, and is exposed from the protective film. The first plane and the second plane are electrically insulated by an insulating film composed of a plurality of fine protrusions, and a radiator for radiating heat generated from the heating element is provided on the insulating film and the insulating film. The first through an inflowing fluid heat transfer material Characterized in that attached to the plane or the second plane.

According to the third aspect of the present invention, the first
, The end face of the long plate-shaped heat-resistant substrate, and a protective film covering a part of the second plane, respectively, and then the first plane and the second plane exposed from the protective film. To electrically insulate, cover with an insulating film consisting of a plurality of fine protrusions,
Since the radiator is attached via the insulating film and the fluid heat transfer material that has entered the insulating film, heat transfer between the long plate-shaped heat-resistant substrate and the radiator becomes good, The heat radiation efficiency of the heat-resistant substrate is improved, and the heat radiator can uniformly and efficiently radiate the heat energy generated during the operation of the heating element.

Therefore, for example, even in a sublimation type high-speed printer or a sublimation printer using a multi-time ribbon, the heat storage in the vicinity of the heating element can be reduced, and the "tailing phenomenon" described above can be avoided. And the image quality is improved. Further, even when printing a plurality of sheets, it is possible to suppress a rise in temperature near the heating element, so that high-quality printing can be performed. That is, if the printing speed is the same, higher quality printing can be performed than the conventional thermal head. In addition, if printing is performed at the same quality as a conventional thermal head, the printing speed can be increased.

According to a fourth aspect of the present invention, there is provided the thermal head according to the first aspect, wherein the area of the open area of the insulating film including the plurality of fine projections is equal to the area of the region where the insulating film is formed. 30-90% of area
It is characterized by being.

According to the fourth aspect of the present invention, the area of the open area of the mesh-like insulating film composed of a plurality of fine projections is 30 to 90% of the area of the region where the insulating film is formed. Therefore, sufficient heat transfer (especially in the case of 90%) and sufficient insulation can be ensured.

A thermal head according to a fifth aspect of the present invention is the thermal head according to any one of the first to fourth aspects, wherein the thickness of the insulating film is the same as the thickness of the protective film or the thickness of the protective film. It is characterized in that it is thinner than the thickness of the film.

According to the fifth aspect of the present invention, since the thickness of the insulating film is equal to or smaller than the thickness of the protective film, the thickness of the long heat-resistant substrate and the radiator can be reduced. The heat transfer distance is reduced, and the radiator can efficiently radiate the heat energy generated during the operation of the heating element.

According to a sixth aspect of the present invention, in the method of manufacturing a thermal head, a plurality of heating elements are arranged in a longitudinal direction of an end surface of the long plate-shaped heat-resistant substrate to form a heating element. Forming a first plane provided with a control element for selectively controlling the plurality of heating elements and supplying power to the conductive substrate, and forming an electrode common to the plurality of heating elements on the long plate-shaped heat-resistant substrate. Is formed, and the vicinity of the heating element is covered with a protective film covering a part of the first plane, an end face of the long plate-shaped heat resistant substrate, and a part of the second plane. A radiator for covering the first plane and the second plane exposed from the protective film with a mesh-like insulating film to electrically insulate and radiating heat generated from the heating element; Through the insulating film and the fluid heat transfer material that has entered the insulating film. Characterized by producing a thermal head by attaching to the first plane or the second plane Te.

According to the sixth aspect of the present invention, the first
, The end face of the long plate-shaped heat-resistant substrate, and a protective film covering a part of the second plane, respectively, and then the first plane and the second plane exposed from the protective film. Since it is covered with a mesh-shaped insulating film for electrical insulation and a radiator is attached via the insulating film and a fluid heat transfer material that has entered the insulating film, a long plate-shaped heat-resistant substrate The heat transfer between the heat sink and the heat radiator is improved, the heat radiating efficiency of the long plate-shaped heat resistant substrate is improved, and the heat radiator can evenly and efficiently radiate the heat energy generated when the heating element operates. Become like

Therefore, even in a sublimation type high-speed printer or a sublimation printer using a multi-time ribbon, for example, the heat storage near the heating element can be reduced, and the occurrence of the "tailing phenomenon" described above can be avoided. And the image quality is improved. Further, even when printing a plurality of sheets, it is possible to suppress a rise in temperature near the heating element, so that high-quality printing can be performed. That is, if the printing speed is the same, higher quality printing can be performed than the conventional thermal head. In addition, if printing is performed at the same quality as a conventional thermal head, the printing speed can be increased.

Further, since the portion away from the heat generating portion can be formed as a conventional insulating film, the radiator is temporarily fixed to the plate-like heat resistant substrate by a simple temporary fixing means such as a double-sided tape on the insulating film. You can also. Therefore, it is possible to manufacture a thermal head having good heat radiation efficiency without reducing the productivity of the thermal head.

According to a seventh aspect of the present invention, in the method for manufacturing a thermal head according to the sixth aspect, an area of an open area of the mesh-shaped insulating film is equal to the insulating area. The area is 30 to 90% of the area of the region where the film is formed.

According to the seventh aspect of the present invention, the area of the open area of the insulating film formed in a mesh is 30 to 90% of the area of the region where the insulating film is formed. The film can be manufactured by applying a practical method such as silk screen printing or seal printing. Further, the thermal head manufactured by this manufacturing method can secure sufficient (especially in the case of 90%) heat transfer and sufficient insulation.

In the method for manufacturing a thermal head according to the present invention, a heating element is formed by arranging a plurality of heating elements in a longitudinal direction of an end surface of a long plate-shaped heat-resistant substrate. Forming a first plane provided with a control element for selectively controlling the plurality of heating elements and supplying power to the conductive substrate, and forming an electrode common to the plurality of heating elements on the long plate-shaped heat-resistant substrate. Is formed, and the vicinity of the heating element is covered with a protective film covering a part of the first plane, an end face of the long plate-shaped heat resistant substrate, and a part of the second plane. To cover the first plane and the second plane exposed from the protective film with an insulating film composed of a plurality of fine projections for electrically insulating the first plane and the second plane, and to radiate heat generated from the heating element. Flow of heat into the insulating film and the insulating film Characterized by producing a thermal head by attaching via the transmitter to the first plane or the second plane.

According to the eighth aspect of the present invention, the first
, The end face of the long plate-shaped heat-resistant substrate, and a protective film covering a part of the second plane, respectively, and then the first plane and the second plane exposed from the protective film. To electrically insulate, cover with an insulating film consisting of a plurality of fine protrusions,
Since the radiator is attached via the insulating film and the fluid heat transfer material that has entered the insulating film, heat transfer between the long plate-shaped heat-resistant substrate and the radiator becomes good, and the long plate-shaped heat-resistant The heat radiation efficiency of the conductive substrate is improved, and the heat radiator can uniformly and efficiently radiate the heat energy generated during the operation of the heating element.

Therefore, for example, even in a sublimation type high-speed printer or a sublimation printer using a multi-time ribbon, the heat storage near the heating element can be reduced, and the occurrence of the "tailing phenomenon" can be avoided. And the image quality is improved. Further, even when printing a plurality of sheets, it is possible to suppress a rise in temperature near the heating element, so that high-quality printing can be performed. That is, if the printing speed is the same, higher quality printing can be performed than the conventional thermal head. In addition, if printing is performed at the same quality as a conventional thermal head, the printing speed can be increased.

Further, since the portion away from the heat generating portion can be formed as a conventional insulating film, the radiator is temporarily fixed to the plate-like heat resistant substrate by a simple temporary fixing means such as a double-sided tape on the insulating film. You can also. Therefore, it is possible to manufacture a thermal head having good heat radiation efficiency without reducing the productivity of the thermal head.

According to a ninth aspect of the present invention, there is provided a thermal head manufacturing method according to the eighth aspect, wherein an area of an open area of the insulating film including a plurality of fine protrusions is the same as that of the insulating film. Characterized in that the area is 30 to 90% of the area of the region in which is formed.

According to the ninth aspect of the present invention, the area of the open area of the insulating film composed of a plurality of fine projections is
Since the area is 30 to 90% of the area of the region where the insulating film is formed, the insulating film can be manufactured by applying a practical method such as silk screen printing or seal printing. Further, the thermal head manufactured by this manufacturing method can secure sufficient (especially in the case of 90%) heat transfer and sufficient insulation.

According to a tenth aspect of the present invention, there is provided a thermal head manufacturing method according to the sixth aspect, wherein the thickness of the insulating film is the same as the thickness of the protective film. Alternatively, the thickness is smaller than the thickness of the protective film.

According to the tenth aspect of the present invention, the thickness of the insulating film is equal to or smaller than the thickness of the protective film. The distance of heat transfer with the heater is reduced, and the radiator can efficiently radiate heat energy generated during operation of the heating element.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a thermal head and a method for manufacturing the same according to the present invention will be described below in detail with reference to the accompanying drawings.

Due to the structure of the thermal head, it is necessary to fix the heat radiator to the long plate-shaped heat-resistant substrate, and at that time, the first or second plane of the long plate-shaped heat-resistant substrate is radiated. However, electrical insulation between the radiator and the long heat-resistant substrate is indispensable. The thermal head of the present invention has a structure in which the vicinity of the first plane or the second plane wrapped around the end surface of the long plate-shaped heat resistant substrate closest to the heating element can be used as a heat transfer path, And prevent the adverse effects of heat storage.

First Embodiment FIG. 1A is an external view of a thermal head according to a first embodiment, and FIG. 1B is an enlarged view of a portion D in FIG. 1A. FIG. 2 is a sectional view taken along line CC of FIG. In this embodiment, the insulation between the radiator and the long plate-shaped heat-resistant substrate is performed by a mesh-shaped insulating film.

As shown in FIG. 1 (a), the long plate-shaped heat-resistant substrate 100 has a flat cutting board shape, and its end face (downward on the paper surface) extends in the longitudinal direction. A plurality of heating elements are arranged so that the heating element 110 is formed. In this embodiment, the long plate-shaped heat-resistant substrate 10 is used.
The material of No. 0 is ceramic. Long plate heat resistant substrate 1
The front side (first plane) and a part of the back side (second plane) of No. 00 secure electrical insulation between the radiator and the long plate-shaped heat-resistant substrate 100 when attached to the radiator. Insulating film 120 is formed. The insulating film 120 is formed as shown in FIG.
It is formed in a mesh shape (mesh shape) as shown in (b),
The thickness of the insulating film 120 is made as thin as possible. In addition,
The fluid heat transfer material enters the depressions 130, 130,... Of the insulating film 120.

As shown in FIG. 2, the thermal head according to the present embodiment extends on the end face 202 of the long heat-resistant substrate 100 extending in the front-back direction of the drawing and extends in the longitudinal direction of the long heat-resistant substrate 100. Is formed, and the heating element 11 in which a plurality of heating elements are arranged is formed on the glaze 204.
0 is formed. On a first plane 208 in the longitudinal direction of the long plate-shaped heat-resistant substrate 100, a pattern on which a control element connected to the heating element 110 for selectively controlling a plurality of heating elements and supplying power is mounted. 210 are formed. On the second plane 212 of the long plate-shaped heat-resistant substrate 100,
An electrode 214 common to a plurality of heating elements of the heating element 110 is formed. In the vicinity of the heating element 110, the first plane 2
08, the end face 202 of the long plate-shaped heat-resistant substrate 100 and the second flat surface 212 are covered with a protective film 216.

In a region where the protective film 216 is not formed on the first plane 208 and the second plane 212, a mesh-like insulating film 120 as shown in FIG. 1B is formed. The recesses 130 of the mesh-like insulating film 120 are provided with the fluid heat transfer material 22 having fluidity and electrical insulation and good heat transfer efficiency.
Fill with 0. The long heat-resistant substrate 100 and the radiator 230 are fixed to each other using a double-sided tape 235 or an adhesive. Note that the fluid heat transfer material 220 may also serve as the adhesive.

Note that, as shown in FIG.
5 or in the case of fixing using an adhesive, the insulating film 1
The portion to which the double-sided tape 235 is applied or the portion to which the adhesive is applied are not mesh-shaped, but a conventional smooth insulating film 240. Also, if a material that also functions as an adhesive is used for the fluid heat transfer material 220, the insulating film 12
It is not necessary to provide the smooth insulating film 240 on a part of 0.

Since the double-sided tape 235 and the adhesive also affect the quality of heat transfer between the long plate-shaped heat-resistant substrate 100 and the radiator 230, the double-sided tape 235 and the adhesive should be made of a material having a large heat transfer coefficient. Is desirable. Since the double-sided tape 235 has a foam layer, the heat transfer coefficient of the double-sided tape 235 is generally about 0.3 × 10 ⁻³ cal / cm · sec · ° C.

The insulating film 120 on the first plane 208 side includes
The protective cover 250 is put on. In addition, on the long plate-shaped heat-resistant substrate 100 side of the radiator 230, the long plate-shaped heat-resistant substrate 10
In order to prevent the flowable heat transfer material 220 from protruding toward the double-sided tape 235 and to reduce the adhesive force when the heat radiator 230 is pressed against and attached to the heat sink 230, an excess flowable heat transfer material 220 is poured. Groove 255 is provided. The shape of the groove 255 depends on the flowable heat transfer material 22 used.
It is desirable to make the shape optimal according to the type of 0.

Incidentally, the heat transfer coefficient of the glaze 204 serving as the heating element 110 for printing by contacting the recording paper is 0.5
× 10 ⁻³ cal / cm · sec · ° C. This portion is intended to store heat for each pixel. The heat transfer coefficient of the long heat-resistant substrate (ceramic substrate) 100 that forms the long heat-resistant substrate 100 that absorbs and transmits the heat energy from the glaze 204 in preparation for printing of the next pixel is 6
It is 0 × 10 ⁻³ cal / cm · sec · ° C., and has a thermal conductivity that is 120 times that of the glaze 204. Further, the heat transfer coefficient of the protective film 216 that transmits heat energy after the glaze 204 is 50 × 10 ⁻³ cal /.
cm · sec · ° C., and the flowable heat transfer material (for example, heat conductive grease, heat conductive adhesive) 220 is 1 to 2
× 10 ⁻³ cal / cm · sec · ° C., the insulating film 120 is 0.5 × 10 ⁻³ cal / cm · sec · ° C., the radiator (for example, aluminum) 230 is 486 × 10 ⁻³ cal / cm.
cm · sec · ° C. As is clear from these numerical values, the heat transfer coefficient of the insulating film 120 is remarkably worse than other members, which impedes the heat radiation of the thermal head.

A unit of thermal conductivity, cal / cm · sec ·
As can be seen from ° C., it can be seen that the degree of transfer of thermal energy changes depending on the distance, time, and temperature difference. Therefore, even with a ceramic substrate having a large thermal conductivity, the heat transfer efficiency increases as the contact area with the radiator 230 increases, and the heat transfer efficiency increases as the contact area with the insulating film 120 decreases. Therefore, in the present invention, the insulating film 120 is formed in a mesh shape, and the fluid heat transfer material 220
, Heat from the long heat-resistant substrate 100 is transmitted to the radiator 230 via the insulating film 120 and the fluid heat transfer material 220.

Specifically, assuming that the thickness of the long plate-shaped heat-resistant substrate 100 is T, the region where the mesh-like insulating film 120 is formed is T or more from the junction between the protective film 216 and the insulating film 120. , Preferably a distance of 2T to 3T. Further, the thickness of the insulating film 120 is preferably made as small as possible. For example, the thickness of the insulating film 120 is equal to or smaller than the thickness of the protective film 216. If the fineness of the mesh is 10 to 100 squares per inch, there is no thermal non-uniformity and the manufacture can be easily performed.
Also, when attaching the long plate-shaped heat-resistant substrate 100 to the radiator 230, for example, a heat conductive grease, a heat conductive adhesive, or the like, which is interposed between the insulating film 120 and the radiator 230. Has a high heat transfer coefficient, preferably 1
A material having a heat transfer coefficient of 10 ³ cal / cm · sec · ° C. or more is used, and its thickness is made as small as possible. As described above, the region where the insulating film 120 is formed is
If the distance from the junction between the insulating film 120 and the insulating film 120 is set to be equal to or longer than T and the thickness of the insulating film 120 is reduced, the heat from the protective film 216 can flow directly through the fluid heat transfer material 220 without passing through the insulating film 120.
The area transmitted to the heat radiator 230 through the heat sink 230 increases, and the distance between the protective film 216 and the heat radiator 230 can be reduced, so that the heat radiation efficiency of the long plate-shaped heat-resistant substrate 100 becomes very large.

As described above, the mesh-shaped insulating film 120 covers a part of the first plane 208 and a part of the second plane 212 over a dimension longer than the thickness T of the long plate-shaped heat resistant substrate 100. Fluid heat transfer material 22 is provided in the depression of the insulating film.
Since 0 is satisfied, heat transfer between the long plate-shaped heat-resistant substrate 100 and the radiator 230 is improved, and heat storage accompanying the operation of the thermal head can be reduced. As a result, the heat radiation efficiency is improved, and the occurrence of the "tailing phenomenon", which has conventionally been concerned, can be avoided as much as possible. Therefore, if the printing speed is the same, higher quality printing can be performed than the conventional thermal head. In addition, if printing is performed at the same quality as a conventional thermal head, the printing speed can be increased.

In the above embodiment, the area of the open area (the recess 13
The total area of the open area is preferably as large as possible in terms of heat transfer.
It is desirable that the upper limit be 90% of the area of the region where 0 is formed, and it is more preferable that the range be 30 to 90%. As for the thickness of the network-like continuous projection, it is better to make the thickness as thin as possible in consideration of the unit of thermal conductivity. Specifically, as shown in FIG.
When 20 is set to 10 grids per inch (mesh 10), it is desirable that the thickness of the mesh-like continuous projection portion of the insulating film 120 is about 5 μm to 20 μm.

The shape of the mesh of the insulating film 120 is a square in the above embodiment, but a diamond as shown in FIG. 4A, a rectangle as shown in FIG. 4B, and a rectangle as shown in FIG. Of course, it may be a rounded shape such as an ellipse.

The thermal head according to the first embodiment is manufactured by the following procedure. First, a glaze 204 extending in the longitudinal direction of the long plate-shaped heat-resistant substrate 100 is formed on the end surface 202 of the long plate-shaped heat-resistant substrate 100 extending in the front-back direction of the drawing. Next, the heating element 110 in which a plurality of heating elements are arranged in the glaze 204 is formed. Then, a pattern 210 for selectively controlling a plurality of heating elements and supplying power is formed on the first flat surface 208 in the longitudinal direction of the long plate-shaped heat-resistant substrate 100. . Further, the second flat surface 21 of the long plate-shaped heat resistant substrate 100
2, an electrode 2 common to a plurality of heating elements of the heating element 110
14 is formed. In the vicinity of the heating element 110, the first plane 2
08, the end face 202 of the long plate-shaped heat-resistant substrate 100 and the second flat surface 212 are covered with a protective film 216.

An insulating material is applied to the area of the first plane 208 and the second plane 212 where the protective film 216 is not formed, and the mesh-like insulating film 120 is formed by silk screen printing or seal printing. A conventional smooth insulating film 240 is formed. When forming an insulating layer for electrically insulating the first plane 208 and the second plane 212 exposed from the protective film, when an insulating material is applied so that only the insulating film 120 overlaps the protective film 216, After the application, the insulating film 120 may be removed using a tool such as a scraper so that the overlapping portion between the protective film 216 and the insulating film 120 is flush. Further, by adjusting the viscosity of the insulating material, the substantial thickness of the insulating film 120 after drying is made smaller than the thickness of the protective film 216. Specifically, the protective film 21
The thickness is set to about 5 to 20 μ according to the thickness of No. 6. Adhering the double-sided tape 235 to the smooth insulating film 240 to fix the long plate heat-resistant substrate 100 and the radiator 230, or applying an adhesive to the smooth insulating film 240 and
00 and the radiator 230 are fixed. Further, a protective cover 250 is attached to the first plane 208 side. The thermal head of the first embodiment is formed by the above procedure.

Second Embodiment FIG. 5A is an external view of a thermal head according to a second embodiment, and FIG. 5B is an enlarged view of a portion E in FIG. 5A. In this embodiment, the insulation between the radiator and the long heat-resistant substrate is performed by the insulating film having the plurality of fine projections formed thereon.

As shown in FIG. 5 (a), the long plate-shaped heat-resistant substrate 100 has a flat cutting board shape, and its end face (downward on the paper surface) extends in the longitudinal direction. A plurality of heating elements are arranged so that the heating element 110 is formed. Note that, also in the present embodiment, the long plate-shaped heat-resistant substrate 10
The material of No. 0 is ceramic. Long plate heat resistant substrate 1
The front side (first plane) and a part of the back side (second plane) of No. 00 secure electrical insulation between the radiator and the long plate-shaped heat-resistant substrate 100 when attached to the radiator. Insulating film 120 is formed.

As shown in FIG. 5B, the insulating film 120 is composed of a region 120A where a conventional smooth insulating layer is formed and a region 120B where a plurality of fine projections are formed. Note that the thickness of the insulating film 120 (in other words, the height of the fine projections) is made as thin as possible. The region 500 other than the fine protrusions of the insulating film 120 is filled with a fluid heat transfer material. With this configuration, when the long plate-shaped heat-resistant substrate 100 and the radiator 230 are fixed to each other, the fluid heat transfer material directly thermally couples the long plate-shaped heat-resistant substrate 100 and the radiator 230. And a long plate-shaped heat-resistant substrate 1
The heat radiation efficiency of 00 is improved.

The unit of thermal conductivity, cal / cm · sec ·
As can be seen from ° C., it can be seen that the degree of transfer of thermal energy changes depending on the distance, time, and temperature difference. Therefore, even with a ceramic substrate having a large thermal conductivity, the heat transfer efficiency increases as the contact area with the radiator 230 increases, and the heat transfer efficiency increases as the contact area with the insulating film 120 decreases. Therefore, according to the present invention, the insulating film 120 is formed of fine protrusions, and the region 500 other than the fine protrusions is filled with the fluid heat transfer material 220 so that the long plate-shaped heat resistant substrate 1
Heat from the heat transfer material 22 and the heat transfer material 22
0 to the radiator 230.

Specifically, the thickness of the long plate-shaped heat-resistant substrate 100
If only T is used, the insulating film 120 of fine projections is formed.
Region from the junction between the protective film 216 and the insulating film 120.
The distance should be longer than T, preferably 2T-3T.
good. Further, the thickness of the insulating film 120 is made as thin as possible.
And good. For example, the thickness of the insulating film 120 is
Or less than the thickness of the protective film 216
I do. The fineness of the mesh is 10 to 100 squares per inch.
The number of stitches has no thermal non-uniformity, making it easy to manufacture
You. Then, the long plate-shaped heat-resistant substrate 100 is attached to the radiator 230.
When attaching, between the insulating film 120 and the radiator 230
Intervening, for example, heat conductive grease, heat
Conductive adhesives, etc., have a large heat transfer coefficient, preferably
Is 1 × 10 ^-3heat transfer over cal / cm · sec · ° C
Use a material that has the same
You.

As described above, the mesh-like insulating film 120 covers a part of the first plane 208 and a part of the second plane 212 over a dimension longer than the thickness T of the long heat-resistant substrate 100, Fluid heat transfer material 22 is provided in the depression of the insulating film.
Since 0 is satisfied, heat transfer between the long plate-shaped heat-resistant substrate 100 and the radiator 230 is improved, and heat storage accompanying the operation of the thermal head can be reduced. As a result, the heat radiation efficiency is improved, and the occurrence of the "tailing phenomenon", which has conventionally been concerned, can be avoided as much as possible. Therefore, if the printing speed is the same, higher quality printing can be performed than the conventional thermal head. In addition, if printing is performed at the same quality as a conventional thermal head, the printing speed can be increased.

In the above embodiment, the area of the open area of the insulating film 120 formed in a mesh shape (the insulating film 1
The total area of the regions 500 other than the 20 fine protrusions) is preferably as large as possible in terms of heat transfer. However, in consideration of the insulation performance of the fine protrusions, the area of the open area is such that the insulating film 120 is formed. 90 of the area of the area
% Is the upper limit, preferably 30 to 90%.
%. As for the thickness of the network-like continuous projection, it is better to make the thickness as thin as possible in consideration of the unit of thermal conductivity. Specifically, FIG.
As shown in the figure, when the number of grids of the insulating film 120 is 10 per inch (2.5 to 0.25 mm pitch), the thickness of the fine projections of the insulating film 120 is about 5 to 20 μm. Is desirable.

The shape of the fine protrusions of the insulating film 120 is square in the above embodiment, but is a star shape as shown in FIG. 7A and a double circle shape as shown in FIG. Of course, it is also good.

The thermal head according to the second embodiment is manufactured by the following procedure. First, a glaze 204 extending in the longitudinal direction of the long plate-shaped heat-resistant substrate 100 is formed on the end surface 202 of the long plate-shaped heat-resistant substrate 100 extending in the front-back direction of the drawing. Next, the heating element 110 in which a plurality of heating elements are arranged in the glaze 204 is formed. Then, a pattern 210 for selectively controlling a plurality of heating elements and supplying power is formed on the first flat surface 208 in the longitudinal direction of the long plate-shaped heat-resistant substrate 100. . Further, the second flat surface 21 of the long plate-shaped heat resistant substrate 100
2, an electrode 2 common to a plurality of heating elements of the heating element 110
14 is formed. In the vicinity of the heating element 110, the first plane 2
08, the end face 202 of the long plate-shaped heat-resistant substrate 100 and the second flat surface 212 are covered with a protective film 216.

In the area of the first plane 208 and the second plane 212 on which the protective film 216 is not formed, a plurality of finely projecting insulating films 120 and a conventional insulating film are formed by silk screen printing or seal printing. A smooth insulating film 240 is formed. When forming an insulating layer for electrically insulating the first plane 208 and the second plane 212 exposed from the protective film, when an insulating material is applied so that only the insulating film 120 overlaps the protective film 216, After the application, the insulating film 120 may be removed using a tool such as a scraper so that the overlapping portion between the protective film 216 and the insulating film 120 is flush. Further, by adjusting the viscosity of the insulating material, the insulating film 120 can be formed.
Is substantially smaller than the thickness of the protective film 216 after drying. Specifically, the thickness is set to about 5 to 20 μ according to the thickness of the protective film 216. The long heat-resistant substrate 100 and the radiator 230 are fixed to each other by bonding a double-sided tape 235 to the smooth insulating film 240, or
An adhesive is applied to 40 to fix the long heat-resistant substrate 100 and the radiator 230 together. Further, a protective cover 250 is attached to the first plane 208 side. The thermal head of the second embodiment is formed by the above procedure.

In the above embodiment, the description has been given of the end face type thermal head. However, the present invention is not limited to this, and the present invention can be applied to a corner edge type thermal head and a flat type thermal head. As the image forming apparatus equipped with the thermal head of the present invention, various image forming apparatuses such as a sublimation type printer, a thermal printer, and a thermal transfer printer can be considered.

[0070]

As described above, according to the first aspect of the present invention, protection for covering a part of the first plane, the end face of the long heat-resistant substrate, and a part of the second plane, respectively. Subsequent to the film, the first plane and the second plane exposed from the protective film are covered with an insulating film formed in a mesh shape to electrically insulate and enter the insulating film and the insulating film. Since the radiator is attached via the fluid heat transfer material, the heat transfer between the long heat-resistant substrate and the radiator is improved, and the heat dissipation efficiency of the long heat-resistant substrate is improved. hand,
The radiator can evenly and efficiently radiate heat energy generated during operation of the heating element. Therefore, the occurrence of the "tailing phenomenon" described above can be avoided, and if the printing speed is the same, higher quality printing can be performed than the conventional thermal head, and printing of the same quality as the conventional thermal head can be performed. In this case, the printing speed can be increased.

According to the second aspect of the present invention, since the area of the open area of the insulating film formed in a mesh is 30 to 90% of the area of the region where the insulating film is formed, a sufficient ( Heat transfer and sufficient insulation can be secured (especially in the case of 90%), heat transfer between the long heat-resistant substrate and the radiator is good, and the heat dissipation efficiency of the long heat-resistant substrate is improved. Thus, the radiator can uniformly and efficiently radiate the heat energy generated during the operation of the heating element. Therefore, there is an effect that occurrence of the "tailing phenomenon" described above can be avoided.

According to the third aspect of the present invention, the protective film covers a part of the first plane, an end face of the long heat-resistant substrate, and a part of the second plane. The first and second planes, which are exposed from, are covered with an insulating film composed of a plurality of fine projections to electrically insulate the first and second planes, and the insulating film and the fluid heat transfer material entering the insulating film are removed. Since the radiator is attached via the heat sink, heat transfer between the long plate-shaped heat-resistant substrate and the radiator is improved, and the heat dissipation efficiency of the long plate-shaped heat-resistant substrate is improved. The heat energy generated during the operation can be evenly and efficiently dissipated. Therefore, the occurrence of the "tailing phenomenon" described above can be avoided, and if the printing speed is the same, higher quality printing can be performed than the conventional thermal head, and printing of the same quality as the conventional thermal head can be performed. In this case, the printing speed can be increased.

According to the fourth aspect of the present invention, the area of the open area of the mesh-like insulating film composed of a plurality of fine projections is reduced by 30 times the area of the region where the insulating film is formed.
９０90%, sufficient heat transfer (especially in the case of 90%) and sufficient insulation can be ensured, and heat transfer between the long plate-shaped heat-resistant substrate and the radiator becomes good. The heat radiation efficiency of the heat-resistant substrate is improved, and the radiator can uniformly and efficiently radiate the heat energy generated during the operation of the heating element. Therefore, there is an effect that occurrence of the "tailing phenomenon" described above can be avoided.

According to the fifth aspect of the present invention, the thickness of the insulating film is equal to or smaller than the thickness of the protective film. The transmission distance is reduced, and the radiator has an effect that the heat energy generated during the operation of the heating element can be efficiently radiated.

According to the sixth aspect of the present invention, the protection film covers a part of the first plane, an end face of the long heat-resistant substrate, and a part of the second plane. The first plane and the second plane exposed from are covered with a mesh-shaped insulating film for electrically insulating, and the insulating film and the fluid heat transfer material that has entered the insulating film are covered with the insulating film. Since the radiator is attached through the radiator, the heat transfer between the long plate-shaped heat-resistant substrate and the radiator becomes good, and the heat dissipation efficiency of the long-plate-shaped heat-resistant substrate is improved. Thermal energy generated during operation can be evenly and efficiently radiated. Therefore, the occurrence of the "tailing phenomenon" described above can be avoided, and at the same printing speed,
Printing with higher image quality than the conventional thermal head can be performed, and if printing is performed at the same quality as the conventional thermal head, the printing speed can be increased.

According to the seventh aspect of the invention, the area of the open area of the insulating film formed in a mesh shape is 30 to 90% of the area of the region where the insulating film is formed. Can be manufactured by applying a practical method such as silk screen printing or sticker printing. Further, the thermal head manufactured by this manufacturing method can secure sufficient heat transfer (especially in the case of 90%) and sufficient insulation, and can perform heat transfer between the long plate-shaped heat-resistant substrate and the radiator. And the heat dissipation efficiency of the long heat-resistant substrate is improved, so that the radiator can uniformly and efficiently radiate the heat energy generated during the operation of the heating element. Therefore, there is an effect that occurrence of the "tailing phenomenon" described above can be avoided.

According to the eighth aspect of the present invention, the protective film covers a part of the first plane, an end face of the long heat-resistant substrate, and a part of the second plane. The first and second planes, which are exposed from, are covered with an insulating film composed of a plurality of fine projections to electrically insulate the first and second planes, and the insulating film and the fluid heat transfer material entering the insulating film are removed. Since the radiator is attached through the radiator, the heat transfer between the long plate-shaped heat-resistant substrate and the radiator becomes good, and the heat dissipation efficiency of the long-plate-shaped heat-resistant substrate is improved. Thermal energy generated during operation can be evenly and efficiently radiated. Therefore, the occurrence of the "tailing phenomenon" described above can be avoided, and if the printing speed is the same, higher quality printing can be performed than the conventional thermal head, and printing of the same quality as the conventional thermal head can be performed. In this case, the printing speed can be increased.

According to the ninth aspect of the present invention, the area of the open area of the insulating film composed of a plurality of fine projections is 30 to 90% of the area of the region where the insulating film is formed. Can be manufactured by applying a practical method such as silk screen printing or sticker printing. Further, the thermal head manufactured by this manufacturing method can secure sufficient heat transfer (especially in the case of 90%) and sufficient insulation, and can perform heat transfer between the long plate-shaped heat-resistant substrate and the radiator. And the heat dissipation efficiency of the long heat-resistant substrate is improved, so that the radiator can uniformly and efficiently radiate the heat energy generated during the operation of the heating element.
Therefore, there is an effect that occurrence of the "tailing phenomenon" described above can be avoided.

According to the tenth aspect of the present invention, the thickness of the insulating film is equal to or smaller than the thickness of the protective film. And the heat transfer distance between the heat radiator and the heat radiator can be effectively reduced.

[Brief description of the drawings]

FIG. 1A is an external view of a thermal head according to a first embodiment, and FIG.
It is a part enlarged view.

FIG. 2 is a sectional view taken along line CC of FIG.

FIG. 3 is a diagram for explaining a pitch of a continuous protruding portion of the thermal head according to the first embodiment;

FIG. 4 is an explanatory diagram of a mesh shape of an insulating film of the thermal head according to the first embodiment;

FIG. 5A is an external view of a thermal head according to a second embodiment, and FIG.
It is a part enlarged view.

FIG. 6 is a diagram for explaining a pitch of a protruding portion of the thermal head according to the second embodiment.

FIG. 7 is an explanatory diagram of a shape of a protrusion of an insulating film of the thermal head according to the second embodiment.

FIG. 8 is a schematic configuration diagram of a conventional thermal head.

FIG. 9 is a sectional view of the thermal head shown in FIG.

FIG. 10 is a schematic configuration diagram of another conventional thermal head.

11 is a sectional view of the thermal head shown in FIG. 10 taken along line BB.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 long plate heat-resistant substrate 110 heating element 120 insulating film 202 end face 204 glaze 208 plane 210 pattern 212 plane 214 electrode 216 protective film 220 fluid heat transfer material 230 radiator 235 double-sided tape 240 smooth insulating film 250 protective cover 255 groove 800 Thermal head substrate 810 Heating element 813 Individual electrode 816 Common electrode 830 Heat sink 840,850 Projection 860 Silicone resin 1000 Projection 1010 Circular part

Claims (10)

[Claims] A heating element is formed by arranging a plurality of heating elements in a longitudinal direction of an end surface of a long plate-shaped heat-resistant substrate, and selectively controlling the plurality of heating elements on the long plate-shaped heat-resistant substrate. A first plane on which a control element for supplying power is provided and a second plane on which a common electrode is formed for the plurality of heating elements are formed, and a part of the first plane, the length The end face of the plate-like heat-resistant substrate, the vicinity of the heating element is covered with a protective film that covers a part of the second plane, and the first plane and the second plane that are exposed from the protective film are It is electrically insulated by an insulating film formed in a mesh shape, and a radiator for radiating heat generated from the heating element is provided through the insulating film and the fluid heat transfer material entering the insulating film. Being attached to the first plane or the second plane A thermal head characterized by the following. 2. The thermal device according to claim 1, wherein an area of an open area of the mesh-shaped insulating film is 30 to 90% of an area of a region where the insulating film is formed. head. 3. A heating element is formed by arranging a plurality of heating elements in a longitudinal direction of an end surface of the long plate-shaped heat-resistant substrate, and selectively controlling the plurality of heating elements on the long plate-shaped heat-resistant substrate. A first plane on which a control element for supplying power is provided and a second plane on which a common electrode is formed for the plurality of heating elements are formed, and a part of the first plane, the length The end face of the plate-like heat-resistant substrate, the vicinity of the heating element is covered with a protective film that covers a part of the second plane, and the first plane and the second plane that are exposed from the protective film are It is electrically insulated by an insulating film composed of a plurality of fine protrusions, and a radiator for radiating heat generated from the heating element is provided through the insulating film and the fluid heat transfer material that has entered the insulating film. Attached to the first plane or the second plane A thermal head, characterized in that: 4. The thermal device according to claim 3, wherein an area of an open area of the insulating film including the plurality of fine protrusions is 30 to 90% of an area of a region where the insulating film is formed. head. 5. The thermal head according to claim 1, wherein the thickness of the insulating film is equal to or smaller than the thickness of the protective film. 6. A heating element is formed by arranging a plurality of heating elements in a longitudinal direction of an end surface of the long plate-shaped heat resistant substrate, and selectively controlling the plurality of heating elements on the long plate-shaped heat resistant substrate. Forming a first plane with a control element for supplying power,
Forming a second plane on the long plate-shaped heat resistant substrate on which electrodes common to the plurality of heating elements are formed; a part of the first plane, an end face of the long plate-shaped heat resistant substrate, the second plane; Covering the vicinity of the heating element with a protective film covering a part of the plane of
A radiator for covering the first plane and the second plane exposed from the protective film with a mesh-like insulating film to electrically insulate and radiating heat generated from the heating element. A method of manufacturing a thermal head, comprising: mounting the thermal head on the first plane or the second plane via the insulating film and a fluid heat transfer material that has entered the insulating film. 7. The thermal device according to claim 6, wherein the area of the open area of the mesh-shaped insulating film is 30 to 90% of the area of the region where the insulating film is formed. Head manufacturing method. 8. A heating element is formed by arranging a plurality of heating elements in a longitudinal direction of an end surface of the long heat-resistant substrate, and selectively controlling the plurality of heating elements on the long heat-resistant substrate. Forming a first plane with a control element for supplying power,
Forming a second plane on the long plate-shaped heat resistant substrate on which electrodes common to the plurality of heating elements are formed; a part of the first plane, an end face of the long plate-shaped heat resistant substrate, the second plane; Covering the vicinity of the heating element with a protective film covering a part of the plane of
The first plane and the second plane exposed from the protective film are covered with an insulating film composed of a plurality of fine projections for electrically insulating the first plane and the second plane, and the heat generated from the heating element is radiated. Manufacturing a thermal head by attaching a radiator to the first plane or the second plane via the insulating film and a fluid heat transfer material penetrating the insulating film. Production method. 9. The thermal device according to claim 8, wherein an area of an open area of the insulating film including the plurality of fine protrusions is 30 to 90% of an area of a region where the insulating film is formed. Head manufacturing method. 10. The thermal head according to claim 6, wherein the thickness of the insulating film is equal to or smaller than the thickness of the protective film. Production method.