JP4467273B2 - Thermal head, manufacturing method thereof, and thermal printer - Google Patents

Description

  The present invention relates to a thermal head that performs printing or the like using heat generated by a heating element, a manufacturing method thereof, and a thermal printer.

Conventionally, the thermal head is incorporated as a printer mechanism such as a word processor, as shown in FIG. 4, a rectangular substrate 11 having a heat generating element array 14 was placed on the heat radiating plate 17 made of a metal such as aluminum structure And a plurality of heating elements constituting the heating element array 14 are selectively Joule-heated individually based on image data from the outside, and the generated heat is conducted to a recording medium such as thermal paper. Then, it functions as a thermal head by forming a predetermined print on the recording medium.

Heat radiating plate 17 absorbs heat in the substrate 11, by dissipating it to the atmosphere, is intended to prevent the temperature of the substrate 11 is excessively high temperatures, above surface A pair of grooves 17 a and 17 b are formed on both sides of the region immediately below the heating element array 14.

Of the between the heat radiating plate 17 substrate 11 in a region between the pair of grooves 1 7a-17b, relatively heat dissipation high resin material 18, the other regions sided tape 19 a, 19b is Each intervenes.

Resin material 18 is configured to bond the substrate 11 and the heat radiating plate 17, without an effect of satisfactorily conducted to the heat radiating plate 17 side heat in the substrate 11, also double-sided tape 19 a, 19b, the substrate 11 And the heat radiating plate 17 are bonded.

Note that placing the substrate 11 on the heat radiating plate 17, the fixing is first to prepare the heat radiating plate 17 having a pair of grooves 17 a, 17b (FIG. 5 (a)), then, a pair of grooves between 1 7a-17b, adhered resin 18 '(such as silicone resin, acrylic resin) together with applying the grooves 17a, 17b and the double-sided tape 19 a in a region between the end of the heat radiating plate 13, the 19b and (FIG. 5 (b)), and thereafter, after then places the substrate 11 at a predetermined position of the heat radiator 17, completed by thermally curing the resin 18 'at a temperature of 70 ° C. to 120 ° C. (FIG. 5C).
JP 2001-96780 A

Incidentally, the resin 18 is applied over the heat radiating plate 17 ', since viscous is relatively small, the resin 18 applied to the heat radiator 17' to flow is, a pair of grooves 17a, the interior of 17b If flows, as it is, will flow easily to the bottom surface of the groove 17a, 17b. Thus, 'when there are fewer active resin 18' resin 18 remaining on the heat radiating plate 17 decreases the height of, when mounting the substrate 11 on the heat radiating plate 17, the resin 18 'and the substrate 11 gaps can be either between, will be whether bubbles multi amount is mixed, thereby it is the area where the heat of the substrate 11 is hardly transmitted to the heat radiating plate 17 via the resin material 18. As a result, the amount of heat that also this within the substrate 11 depends on the area, there is a problem that causes unevenness in image density.

The present invention has been devised in view of the above problems, its object is a high performance method for a thermal head and a manufacturing capable of transferring heat of the substrate to better heat dissipation plate, and It is to provide a thermal printer.

Head thermal head of the present invention, the upper surface of the heat sink forming a rectangular shape along the longitudinal direction of the heat dissipating plate has a pair of grooves are formed, which on the heat radiating plate has a heating element array A substrate is placed so that a region directly under the heat generating element row is located between the pair of grooves, and a region directly under the heat generating element row is between the head substrate and the heat radiating plate. In the thermal head in which the double-sided tape is interposed in the other region, the resin material is disposed on the inner wall surface of the groove disposed on both sides of the upper surface of the heat radiating plate immediately below the heating element array. A plurality of slits along the direction are provided.

The thermal head of the present invention, in the thermal head described above, it is preferable that the slits are arranged at a density of 2 / Mm～70 lines / mm in the thickness direction of the heat radiating plate.

On the other hand, manufacturing method for a thermal head of the present invention is a heat dissipation plate forming a rectangular shape, a pair of grooves are formed along the longitudinal direction of the heat dissipating plate on the upper surface of the heat radiating plate, said groove wherein the side wall surfaces which are disposed on opposite sides of the upper surface of the heat radiating plate between said pair of grooves of the inner wall surface, a plurality of slits the are arranged along the longitudinal direction of the grooves are formed radiating A first step of preparing a plate and a head substrate having a heating element array; and applying a resin to a region between the pair of grooves on the upper surface of the heat radiating plate; And a third step of placing the head substrate on the heat sink so that a region directly under the heating element row is located in a region between the pair of grooves. It manufactures through a process and the 4th process of hardening the said resin.

The manufacturing method for a thermal head of the present invention, in the first step, preparing a heat sink wherein the slits are formed at a density of 2 / Mm～70 lines / mm in the thickness direction of the heat radiating plate It is preferable .

Then, the thermal printer of the present invention is a thermal head described above, a conveying means for conveying the recording medium onto said thermal head, driving means for driving said thermal head, comprising the.

According to the present invention, a pair of grooves are formed along the longitudinal direction of the heat dissipating plate on the upper surface of the heat sink forming a rectangular shape, on the heat radiating plate, the head substrate having a heating element array but with a region immediately below the heat generating element array is mounted so as to be positioned between the pair of grooves, one between the head substrate and the heat radiating plate, the region immediately below the heat generating element array the resin material in the thermal head is interposed respectively double-sided tape to the other areas, said inner wall surface of the groove Ru Tei disposed on both sides of the upper surface of the heat radiating plate immediately below the heat generating element array, the longitudinal of said groove Since a plurality of slits are provided along the direction, even if the resin applied on the heat sink located between the pair of grooves flows into the grooves, the flow is improved by the slits. It will be locked up, and there are relatively many on the heat sink. Resin was residual, it can be kept high the height of the resin. Therefore, when the head substrate is placed on the heat sink, it is possible to prevent a gap from being formed between the head substrate and the resin material or a large amount of air bubbles from being mixed into the head substrate. The accumulated heat is satisfactorily transmitted to the heat sink via the resin material, and an image can be recorded with a desired density.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Figure 1 is a cross-sectional view of a thermal head according to an embodiment of the present invention, the thermal head shown in the figure, a large substantially, resin material 8 of the head substrate 1, double-sided tape 9a, the heat radiating plate 7 through 9b It has a structure placed on top.

Head substrate 1, alumina ceramics, single crystal silicon, Fe - a variety of materials such as Ni alloys, the upper surface of the base plate 2 formed so as to form a rectangular shape, the partial glaze layer 3, the heat generating element array 4, the electrode pattern 5 etc. are attached.

The base plate 2, the partial glaze layer 3 above surface, heating element array 4, which functions as a supporting base material for supporting the electrode patterns 5 etc., for example, if made of alumina ceramics, alumina, silica, ceramic raw material of magnesia powder in a suitable organic solvent, addition of a solvent, together with forming a mud漿状mixed, this well-known doctor blade method, to form a ceramic green sheet by employing a calender roll method or the like, and thereafter, the on punched ceramic green sheets in a rectangular shape, it is manufacturing by firing at high temperatures.

On the upper surface of the base plate 2, heating element array 4 is disposed through the partial glaze layer 3 made of glass or the like.

The partial glaze layer 3 is formed, for example, so as to have a circular arc shape with a radius of curvature of 1 mm to 4 mm, and the thickness of the top is set to 20 μm to 80 μm.

The partial glaze layer 3 is, for example, the thermal conductivity is formed by a glass of 0.7W / m · K~1.0W / m · K, the heat generating elements constituting the heat generating element array 4 at an inner portion Acts as a heat storage layer that accumulates part of the heat and maintains the thermal response of the thermal head well, specifically, increases the temperature of the heating element to a predetermined temperature required for printing in a short time. Do it.

The partial glaze layer 3 is obtained by printing and applying a predetermined glass paste obtained by adding and mixing an appropriate organic solvent to glass powder on the upper surface of the base plate 2 by screen printing or the like. Formed by baking at high temperature.

Partial glaze layer heating element array 4 provided near the top of the 3 is made by arranging linearly a plurality of heating elements for example in the dot density of 300dpi, these heating elements are made of electrically resistive material of tantalum nitride because you are, circuit conductors (not shown) and via a driver IC predetermined power is applied, a predetermined temperature required to form the printing on the recording medium of the heat-sensitive paper or the like (150 ℃ ~400 ℃).

In addition , the electrode pattern 5 connected to both ends of each heating element is formed in a predetermined pattern from a metal material such as aluminum (Al) , copper (Cu), etc., and feed wiring for supplying predetermined power to the heating element Function as.

The heating element array 4 and the electrode pattern 5 are formed on the upper surface of the base plate 2 so as to form a predetermined pattern by adopting a conventionally well-known thin film forming technique, specifically, sputtering, photolithography technique, etching technique or the like. Deposited and formed.

On the other hand, a protective film 6 is deposited on the upper surfaces of the heating element rows 4 and the electrode patterns 5, and the heating element rows 4 and the electrode patterns 5 are covered in common by the protective film 6.

Protective film 6, silicon nitride, silicon oxide, sialon (Si - Al - O - N ) consists excellent inorganic material abrasion resistance, such as, sliding contact of the heating element array 4, an electrode pattern 5 such as a recording medium It protects against corrosion caused by contact due to wear due to moisture and moisture contained in the atmosphere.

The protective film 6 described above, conventionally known thin film forming techniques, employing for example a CVD (Chemical Vapor Deposition) method, a sputtering, silicon nitride, silicon oxide, sialon (Si - Al - O - N ) minerals such as It is formed by depositing the material on the upper surface of the heating element array 4 , the electrode pattern 5, etc. to a thickness of 5 μm to 10 μm.

The head substrate 1 described above, on the heat dissipation plate 7 having a pair of grooves 7a, 7b on the upper surface, directly below the area of the heating elements row 4 is a pair of grooves 7 a - so as to be positioned between 7b placed Is done. Further, in the region between the heat radiating plate 7 the head substrate 1, a pair of grooves 7 a - between 7b, the resin material 8 is interposed, between the grooves 7a and the end portion of the heat radiating plate 7, 及 Binimizo between 7b and the end portion of the heat radiating plate 7, the double-sided tape 9a, 9b are interposed.

Radiating plate 7 is aluminum, it is formed a rectangular shape formed Suyo a metal such as SUS, while supporting the head substrate 1 above surface, through the resin material 8 to be described later heat in the head substrate 1 The head substrate 1 is prevented from becoming excessively high temperature by absorbing and absorbing it into the atmosphere.

The pair of grooves 7a provided on the heat radiating plate 7, 7b is radiating plate 7 are formed substantially parallel to the longitudinal direction of the head substrate 1 in the assembly process of the thermal head, the resin material 8 when placed on the radiating plate 7 via accommodates a surplus of the resin material 8 at the inner portion, the head substrate 1 - effect of substantially constant width of the resin material 8 is interposed between the heat radiating plate 7 Do it.

Such a pair of grooves 7a, the inner wall surface of 7b, specifically, on the inner wall surface which is disposed on both sides of the upper surface of the heat radiating plate 7 is positioned immediately below the heat generating element array 4, a plurality of slits 7c grooves 7a, 7b It is provided along the longitudinal direction.

A plurality of slits 7c is arranged at a density of one / Mm～70 lines / mm in the depth direction of the heat radiating plate 7, each for example depth 5Myuemu～200myuemu, it is set respectively to the width 5μm~100μm . Such plurality of slits 7c is surplus groove 7a of resin material 8, the good halt it from flowing in a large amount to the bottom surface of 7b, makes the effect of leaving a resin material 8 to the heat radiator 7. The heat radiating plate 7 has a conventionally known drawing method (extrusion method), more specifically, a mold having an outer shape of the heat radiating plate 7 including a pair of grooves 7a, 7b and slits 7c made of aluminum or the like. a pair of grooves 7a by pushing in, 7b, are found provided integrally with slits 7c.

On the other hand, the resin material 8 interposed between the head substrate 1 and the heat radiating plate 7 and between the pair of grooves 7a-7b has a thermal conductivity of 0.7 W / (m · K) or more at 25 ° C., for example. silicone resin, heat dissipation of the good resin consisting of acrylic resin, or, good thermal conductivity of _Al 2 _O 3, Si or the like in these resins _(Al 2 _{O 3} of thermal conductivity: 20W at 25 ° C. / (M · K)) inorganic particles (particle size: 3 μm to 30 μm) are preferably added and mixed at a ratio of 20 wt% to 80 wt%. This resin material 8 is formed by thermosetting the above-mentioned resin applied on the heat sink 7 at a temperature of 70 ° C. to 120 ° C. Here, (under the temperature condition of 25 ° C., if the viscosity was measured at Yamaichi Electric Co., Ltd. vibration type viscometer VM-1G, 20~70Pa · s) resin viscosity is relatively low, the fluidity because it has a portion of the resin applied to the heat radiator 7 tends to flow into the inside of the groove 7a, 7b. In this case, as described above, the grooves 7a, the inner wall surface of 7b, since it is provided with a plurality of slits 7c becomes a possible flow of the resin is satisfactorily halt, the number of resin on the heat radiating plate 7 It can be made to remain, and the height of this resin can be kept high. Accordingly, or a gap is formed between the head substrate 1 and the resin member 8, a large amount of air bubbles is prevented from or mixed, the heat of the head substrate 1, the heat radiating plate 7 through the resin material 8 It can dissipate well.

The formation density of the slits 7c is preferably set to 20 lines / Mm～50 present / mm. The reason is that if the formation density of the slits 7c is smaller than 20 / mm, the effect of keeping the resin applied on the heat sink 7 high cannot be increased so much, while the formation of the slits 7c is not achieved. This is because if the density is higher than 50 / mm, the pattern is too fine and the productivity of the heat sink 7 may be reduced.

On the other hand, double-sided tape 9a interposed between the head substrate 1 radiating plate 7 with resin material 8, 9b is an acrylic resin suitable double-sided tape as a base material, and the lower surface of the head substrate 1, heat radiation It has substantially the same thickness (50 μm to 125 μm) so that the upper surface of the plate 7 is positioned substantially in parallel. The double-sided tape 9a, 9b is an action to adhere firmly to the head substrate 1 with respect to the heat radiating plate 7.

Then, place the head substrate 1 on the heat radiating plate 7 described above, the method of fixing will be described in detail with reference to FIG.

First , a heat sink 7 having a pair of grooves 7a, 7b and slits 7c is prepared (FIG. 2 (a)), and then double-faced tapes 9a, 9b are adhered to predetermined areas on the upper surface of the heat sink 7. Then, a resin 8 ′ is applied to the region between the pair of grooves 7a-7b using a dispenser or the like (FIG. 2B).

At this time, as described above, even if a large amount of the applied resin 8 ′ flows into the pair of grooves 7a and 7b , the resin 8 ′ is formed by the slit 7c provided on the inner wall surface of the grooves 7a and 7b. Is effectively prevented from reaching a large amount of the resin 8 'to the bottom surfaces of the grooves 7a and 7b, and the height of the resin 8' remaining between the pair of grooves 7a-7b is effectively prevented. Can be kept high.

Subsequently, the above-described head substrate 1 is placed so that the region immediately below the heating element array 4 is positioned between the pair of grooves 7a-7b (FIG. 2C).

At that time, 'because has a sufficient height, the head substrate 1 resin 8' resin 8 on the radiating plate 7 by a slit 7c described above can be favorably contact with the resin 8 ' And a gap between the head substrate 1 and a large amount of air bubbles can be suppressed.

Finally, the resin substrate 8 is thermally cured to form the resin material 8, whereby the head substrate 1 and the heat sink 7 are firmly bonded and fixed (FIG. 2D).

Since there are no gaps or a large amount of bubbles between the resin material 8 formed in this way and the head substrate 1, the heat accumulated in the head substrate 1 is transferred to the heat sink 7 via the resin material 8. The thermal head can be transmitted well and can record an image at a desired density.

Thus , the thermal head of the present invention causes the plurality of heating elements constituting the heating element array 4 to selectively generate Joule heat individually based on image data from the outside, and the generated heat is used as a recording medium such as thermal paper. And function as a thermal head by forming a predetermined print on the recording medium.

In the thermal printer in which the thermal head as described above is incorporated, as shown in FIG. 3, the driving means C for driving the thermal head T and the conveying means for conveying the recording medium onto the heating element array 4 of the thermal head T are provided. A platen roller 10 and a transport roller 11 are disposed.

The driving means C includes a driver IC in which a shift register , a latch, a switching transistor and the like are integrated at a high density, a control circuit for supplying a control signal such as a strobe signal and a latch signal to the driver IC , and the like. The heat generation of the heating element array 4 is controlled by switching on and off of the switching transistor in the driver IC based on the control signal.

On the other hand, the platen roller 10 as a conveying means is a cylindrical member in which butadiene rubber or the like is wound around the outer periphery of a shaft core made of a metal such as SUS to a thickness of about 3 mm to 15 mm. The recording medium is conveyed in a direction (arrow direction in the figure) orthogonal to the arrangement of the heating element rows 4 while being rotatably supported on the head 4 and pressing the recording medium against the heating element rows 4.

The transport roller 11, the metal outer periphery are formed by rubber or the like is disposed is divided into the upstream side and the downstream side in the transport direction of the recording medium to the thermal head T, these conveying rollers 11 and the platen roller 10 described above support the running of the recording medium.

At the same time, the plurality of heating element arrays 4 are selectively Joule-heated as the driving means C is driven, and these heats are conducted to the recording medium, whereby a predetermined print is formed.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.

For example, in the above-described embodiment, if the formation density of the slits 7c provided in the pair of grooves 7a and 7b is set larger in the groove 7a on the downstream side than the groove 7b on the upstream side in the conveyance direction of the recording medium , it is downstream in the conveyance direction . Since the groove 7a on the side has a greater effect of blocking the resin, the contact area between the resin material 8 and the base plate 2 can be made larger on the downstream side than on the upstream side in the transport direction. Therefore, the heat dissipation is enhanced in the downstream area in the transport direction with respect to the heating element array 4, and the thermal head is prevented from becoming excessively high in the downstream side. As a result, when a recording operation is performed using, for example, thermal paper as a recording medium, the thermal paper that has passed over the heating element array 4 is prevented from being strongly adhered to the protective film 6 due to the heat accumulated in the thermal head. Thus, when the thermal paper in contact with the protective film 6 is peeled off from the protective film 6 , it is possible to satisfactorily prevent a large noise from occurring, and to reduce the noise during the recording operation.

Experimental example

(First Experiment Example)
Next , the function and effect of the present invention will be described based on the first experimental example.

The first experiment, a sample of the heat radiating plate provided with slits on the inner wall surface of the pair of grooves (sample No.4 ~ No.21), a sample of the heat sink without the slits on the inner wall surface of the pair of grooves (Sample the No.1 ~ No.3) and were prepared in accordance with the conditions of Table 1, the resin of a predetermined amount in the region between the pair of grooves on these samples (1 mm ² per about 1 mm ³⁾ was applied, it is that to measure the height of the resin remaining on the heat radiating plate which is positioned between the pair of grooves. As the resin, using a TSE series manufactured by Toshiba Silicone Co., when the viscosity is measured by Yamaichi Electric Co., Ltd. vibration type viscometer VM-1G, 30Pa · s at 25 ℃, 50Pa · s, 60Pa · Three types of s were used. The distance between the pair of grooves was 4 mm, the pair of groove width, both the depth 1 mm, the width of the slit, the depth both the 10 [mu] m. The results of the first experiment described above are shown in Table 1.

According to Table 1, sample no . 4 to No. Sample No. 21 is provided with no slit . 1 - No. It was possible to increase the height of the resin of the heat radiator as compared to 3. In particular, the sample formation density of the slits (formation density to the thickness direction of the heat sink) is 20 or more / m m No. 10 - No. In No. 21 , even when the viscosity of the resin was as low as 30 Pa · s, the height of the resin could be increased.

(Second Experimental Example)
Next , the effect of this invention is demonstrated based on a 2nd experiment example.

In the second experiment , sample No. of the heat sink used in the first experiment . 1 - No. With respect to thermal head samples ( No. 1 to No. 21 , the numbers are in accordance with the samples of the first experimental example) in which the head substrate is placed on 21 and the resin material is thermoset to form a resin material A running test (printing on 25 sheets of A4 paper) with test pattern printing was performed using the sample, and the density unevenness of the recorded image was measured. As the double-sided tape used was a 80 [mu] m. The experimental results of this are shown in Table 2.

According to Table 2, sample no . 5 - No. Sample No. 21 is provided with no slit . 1 ~ No. Compared to 3 , the density unevenness was small. It has a high level of applied resin, when placing the head substrate on the heat radiating plate, the resin tends to contact with the head substrate, therefore, air bubbles between the head substrate and the resin material It is thought that it is difficult to mix. Further, the sample formation density of the slits (formation density to the thickness direction of the heat sink) is 20 or more / m m No. 10 - No. In No. 21 , the density unevenness was small even when the viscosity of the resin was as low as 30 Pa · s.

Above, than the first and second experimental examples, by providing a slit on the inner wall surface of the groove, the heat radiation plate seen that it is possible to maintain high the height of the remaining resin on the. Therefore, when is placed on the head substrate to the heat radiator, or a gap between the head substrate and the resin material, or it is possible to prevent the air bubbles or contamination, accumulated within the head substrate It can be seen that heat is transferred well to the heat sink via the resin material, and an image with little density unevenness is obtained.

It is sectional drawing of the thermal head which concerns on one form of the thermal head of this invention. (A) ~ (d) is the manufacturing method for a thermal head of FIG. 1, places the head substrate to the heat radiating plate, a cross-sectional view for explaining a method of fixing. FIG. 2 is a schematic view of a thermal printer configured by incorporating the thermal head of FIG. 1. It is sectional drawing of the conventional thermal head. (A) ~ (c) is a method of manufacturing a conventional thermal head, placing a substrate to the heat radiating plate, a cross-sectional view for explaining a method of fixing.

DESCRIPTION OF SYMBOLS 1 ... Head substrate 2 ... Base plate 3 ... Partial glaze layer 4 ... Heat generating element row 5 ... Electrode pattern 6 ... Protective film 7 ... Heat sink 7a, 7b ... Pair Groove 7c ... slit 8 ... resin material 9a, 9b ... double-sided tape 10 ... platen roller 11 ... transport roller T ... thermal head C ... drive means

Claims (5)

The upper surface of the heat sink forming a rectangular shape along the longitudinal direction of the heat dissipating plate has a pair of grooves are formed, on the heat radiating plate, the head substrate having a heating element array is, the heat generating element array Is placed so that the region directly below is located between the pair of grooves, and the resin material is placed in the region directly below the heating element row between the head substrate and the heat radiating plate. In thermal heads that have double-sided tape interposed between them,
A thermal head characterized in that a plurality of slits along the longitudinal direction of the groove are provided on the inner wall surface of the groove disposed on both sides of the upper surface of the heat radiating plate immediately below the heating element array.   2. The thermal head according to claim 1, wherein the slits are arranged at a density of 2 lines / mm to 70 lines / mm in the thickness direction of the heat radiating plate. A heat dissipation plate forming a rectangular shape, a pair of grooves are formed along the longitudinal direction of the heat dissipating plate on the upper surface of the heat radiating plate, between the pair of grooves of the inner wall surface of the groove wherein the inner wall surface which is provided on both sides of the upper surface of the heat sink, wherein has said radiating plate having a plurality of slits are formed that are arranged along the longitudinal direction of the groove, the heat-generating-element array head A first step of preparing a substrate;
A second step of applying a resin to the region between the pair of grooves on the upper surface of the heat sink and applying a double-sided tape to the other region;
A third step of placing the head substrate on the heat radiating plate so that a region immediately below the heating element row is located in a region between the pair of grooves;
A method of manufacturing a thermal head, comprising: a fourth step of curing the resin.   The thermal plate according to claim 3, wherein, in the first step, a heat radiating plate in which the slits are formed at a density of 2 / mm to 70 / mm in the thickness direction of the heat radiating plate is prepared. Manufacturing method of the head.   A thermal printer comprising the thermal head according to claim 1, a transport unit that transports a recording medium onto the thermal head, and a drive unit that drives the thermal head.

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