JP3164686B2 - Glaze substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glaze substrate used for a thermal head, an electronic circuit board and the like.

[0002]

2. Description of the Related Art In recent years, printing apparatuses such as facsimile machines and printers have been developed for home use and personal use. When a printing device such as a facsimile is configured using a thermal head, a power source is required to be reduced in size in order to reduce the cost and size of the device.

In order to meet such demands, it is necessary to save energy and improve the printing efficiency of the entire printing apparatus. Therefore, the heat of the heating element provided on the glaze layer constituting the thermal head causes the heat of the lower surface of the glaze layer to be reduced. In order to prevent the heat from escaping to the insulating base and reduce the energy consumption of the heating element, it has been proposed to introduce a bubble into the glaze layer to increase the heat storage effect.

However, when bubbles are introduced into the glaze layer, the surface smoothness is reduced due to the influence of the bubbles, and the yield of the thermal head is reduced. In addition, the variation in the resistance value is increased, which adversely affects the print quality. Was.

[0005] In order to solve the above-mentioned problem, as shown in FIG.
The glaze layer 9 is provided, and the second glaze layer 10 is coated on the upper surface of the first glaze layer 9 to smooth the surface, reduce the thermal conductivity of the first glaze layer 9, and form a fine electrode pattern. A thermal head and a method of manufacturing the same have been proposed (see JP-A-3-128256).
In the figure, reference numeral 11 indicates a resistor, and reference numeral 12
Indicates an electrode, and reference numeral 13 indicates overglass.

In such a thermal head, the heat storage effect can be improved by including minute bubbles in the first glaze layer 9, and the surface of the first glaze layer 9 whose surface smoothness has been reduced due to the influence of the bubbles. A second glaze layer 1
0, it is possible to form a fine electrode pattern.

[0007]

However, the second glaze layer 9 containing a large number of fine air bubbles is not covered.
If the thickness of the glaze layer 10 is too thin, undulation occurs on the surface of the second glaze layer 10 due to the unevenness due to bubbles, and the surface smoothness is reduced. Therefore, when the thin film circuit (electrode pattern) is formed, it is stable. There was a problem that characteristics could not be obtained.

On the other hand, if the thickness of the second glaze layer 10 is too large, the volume of the glaze layer 15 composed of the first glaze layer 9 and the second glaze layer 10 becomes large, the heat capacity becomes large, and the heat storage / dissipation property becomes poor. There was a problem of deterioration. For this reason, when coloring the heat-sensitive recording paper which comes into contact with the over-glass 13, so-called tailing occurs due to the remaining heat, and there is a problem that the printing characteristics are poor and the printing is not suitable for high-speed printing.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a glaze substrate capable of reliably smoothing the surface of a glaze layer and improving printing characteristics. I do.

[0010]

The glaze substrate of the present invention comprises a first glaze layer including a large number of pores having an average diameter of 5 to 10 μm on an insulating substrate, and a surface of the first glaze layer formed of glass. A dense second glaze layer having a thickness of 11 to 30 μm, wherein the second glaze layer has a lower glaze layer for preventing movement of pores from the first glaze layer, and a surface of the second glaze layer. And a glaze upper layer for smoothing

Here, the first glaze layer has an average diameter of 5-1.
The pores having a diameter of 0 μm are included because pores having an average diameter of less than 5 μm have a low thermal conductivity of the first glaze layer and a low print density, and a pore having an average diameter of more than 10 μm This is because the heat storage effect of one glaze layer is large, the heat dissipation is deteriorated, and bleeding occurs at the time of printing.

The reason why the dense second glaze layer having a thickness of 11 to 30 μm is formed on the surface of the first glaze layer is as follows.
When the thickness of the glaze layer is less than 11 μm, the first
This is because unevenness due to pores of the glaze layer affects the surface of the second glaze layer, causing density unevenness in printing characteristics. When the thickness of the second glaze layer is greater than 30 μm, the heat storage effect of the first glaze layer This is because heat dissipation becomes worse, and bleeding or tailing occurs at the time of printing.

[0013]

According to the present invention, the exposed surface of the first glaze layer containing a large number of pores having an average diameter of 5 to 10 μm is covered with a second glaze layer made of glass having a thickness of 11 to 30 μm, thereby smoothing the glaze layer surface. And the printing characteristics of the glaze layer can be improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. FIG. 1 is a sectional view showing one embodiment of the glaze substrate of the present invention. In the figure, reference numeral 31 indicates an insulating substrate. The upper surface of the insulating substrate 31 has a density of 1.5 to
A first glaze layer 33 of 2.5 g / cm ³ is formed, and on the upper surface of the first glaze layer 33, the first glaze layer 33 is formed.
The second having a density of 2.8 to 3.3 g / cm ³ so as to enclose the
A glaze layer 35 is formed. The second glaze layer 35 is composed of a lower glaze layer 37 and an upper glaze layer 39, and the upper glaze layer 39 is the first glaze layer 3
Softening point equal to or less than 3, for example, 800 ° C
Of softening point. The softening point of the first glaze layer 33 is, for example, 856 ° C., and the lower glaze layer 37 has a higher softening point than the first glaze layer 33 and the upper glaze layer 39, for example, 890 ° C. .

The material of the insulating base 31 is preferably similar to the coefficient of thermal expansion of the glass used for the upper glaze layer 39. For example, the alumina (Al ₂ O ₃ ) content is 90 to 9%.
It is composed of 9.5% alumina ceramics.

First glaze layer 33, second glaze layer 35
The material of the glass used for SiO ₂ -Al ₂
O ₃ -CaO-BaO system, SiO ₂ -BaO-PbO
System, SiO ₂ -Al ₂ O ₃ -BaO-based, CaO-B ₂ O
₃ -SiO _{2 system, SiO 2 -B 2 O 3 -PbO} -Al 2
O ₃ —CaO—MgO system, SiO ₂ —BaO—PbO—
_{CaO-Al 2 O 3 -B 2} O 3 system, ZnO-B ₂ O ₃ -
SiO ₂ system, PbO—ZnO—B ₂ O ₃ system, SiO ₂ −
BaO-CaO _{system, PbO-SiO 2 -B 2 O} 3 system and the S
_{iO 2 -Al 2 O 3 -SrO-} CaO system, etc. can be preferably used.

For example, as the glass used for the first glaze layer 33, SiO ₂ is 40 to 60% by weight, Al ₂
The lower glaze layer 3 of the second glaze layer 35 is composed of 5 to 10% by weight of O ₃ and 10 to 30% by weight of BaO.
As the glass used in No. 7, SiO ₂ is 50-60.
Wt%, Al ₂ O ₃ 5 to 10 wt%, a BaO. 10 to
The glass used for the glaze upper layer 39 of the second glaze layer 35 includes 25% by weight.
The SiO ₂ 40 to 50 wt%, the Al ₂ O ₃ 2 to 8 wt%, and containing 25 to 40% by weight of BaO.

In order to form pores in the first glaze layer 33, pores having an average diameter of 5 to 10 μm are formed in the glass by containing a foaming agent in the glass and firing at a predetermined temperature. As the foaming agent, ceramics having an oxidative decomposition temperature higher than the glass softening temperature, for example, aluminum nitride (A
1N), silicon nitride (Si ₃ N ₄ ), boron nitride (BN) and other fine nitride-based ceramics having a fine particle size can be suitably used. In addition, it is a matter of course that pores may be formed in the first glaze layer 33 by selectively eluting a composition having a certain characteristic in the glass by, for example, etching without using a foaming agent.

The thickness of the second glaze layer 35 is 1
It is 1 to 30 μm. This is the second glaze layer 3
If the thickness of 5 is less than 11 μm, undulation occurs on the glaze surface due to the unevenness of the bubbles, and the surface smoothness is reduced, so that when a thin film circuit is formed, stable characteristics cannot be obtained. If the thickness is more than 30 μm, the volume of the glaze layer composed of the first glaze layer 33 and the second glaze layer 35 cannot be reduced, so that the heat capacity increases, the heat storage dissipating property deteriorates, and the printing characteristics deteriorate. is there. The optimum thickness of the second glaze layer 35 is 13 to 20 μm. The thickness of the first glaze layer 33 is 20 to 60 μm.
m is preferable, and particularly preferably 40 to 50 μm.

The thickness of the lower glaze layer 37 of the second glaze layer 35 is 4 to 10 μm, and the thickness of the upper glaze layer 39 is 7 to 20 μm. The reason why the thickness of the glaze lower layer 37 is set to 4 to 10 μm is that if the thickness is smaller than 4 μm, pores of the first glaze layer 33 may be exposed, and if the thickness is larger than 10 μm, the heat capacity of the glaze layer becomes large and heat storage and dissipation is performed. This is because the properties tend to deteriorate. Further, the thickness of the glaze upper layer 39 is set to 7 to 20 μm.
The reason is that if the thickness is smaller than 7 μm, the surface of the second glaze layer 35 may be insufficiently smoothed, and if the thickness is larger than 20 μm, the heat capacity of the glaze layer tends to be large, and the heat storage dissipation tends to deteriorate. is there.

The glaze substrate configured as above is
For example, borosilicate glass having a softening point of 856 ° C. is added to silicon nitride (Si) having a purity of 98% and an average particle size of 0.5 μm.
Using a glass paste to which 0.1% by weight of a foaming agent made of ₃ N ₄ ) powder is added, screen printing is performed so as to have a thickness of 50 μm on an insulating substrate 31 made of an alumina sintered body. A mixed first glass layer is formed. This first glass layer becomes a first glaze layer 33 having a thickness t ₁ = 45 μm after firing.

Next, borosilicate glass (softening point 890) which is a main component of the lower glaze layer 37 of the second glaze layer 35
C.), and a lower glass layer having a thickness of 15 μm, which completely covers the first glass layer, is formed by screen printing. This lower glass layer becomes a glaze lower layer 37 having a thickness t ₂ = 8 μm after firing. The presence of the glaze lower layer 37 can prevent bubbles from moving from the first glaze layer 33 to the second glaze layer 35.

Further, using a glass paste made of borosilicate glass (softening point: 800 ° C.), which is a main component of the glaze upper layer 39, the upper glass layer having a thickness of 25 μm covering the lower glass layer completely is covered. Formed by screen printing. This upper glass layer has a thickness t ₃ = 1 after firing.
It becomes the glaze upper layer 39 of 2 μm. This glaze upper layer 3
9, the glaze layer surface can be smoothed.

Thereafter, the first glaze layer 33 is held at a temperature of 1000 ° C. for 10 minutes and fired, and the size of the first glaze layer 33 is about 6 m in width.
m, length about 230 mm, thickness t ₁ = 45 μm, dimensions of the outermost second glaze layer 35 are about 7 mm in width and about 230 in length
A glaze substrate having a thickness of ₂ mm and a thickness of t ₂ + t ₃ = 20 μm was prepared. The average diameter of the pores in the first glaze layer 33 is 6
μm. The average diameter of the pores was determined by averaging the diameter of the pores in one section of the first glaze layer 33.

When the Ra of the second glaze layer was measured by a surface roughness meter, it was 0.04 μm, and it was confirmed that the smoothness was good. Also, the second glaze layer 35
A resistor and an electrode were sequentially formed on the surface of the substrate to form a thermal head, and the remaining heat was used to test the print characteristics of the glaze layer based on whether or not so-called tail bleeding or bleeding occurred. It was confirmed that it was good.

The present inventors have variously changed the thickness of the second glaze layer 35 and the first glaze layer 33 and the average pore diameter of the first glaze layer 33 in the above glaze substrate, and The surface roughness and the printing characteristics of the glaze layer were tested as described above. Table 1 shows the results.

[0027]

[Table 1]

According to Table 1, when the average diameter of the pores of the first glaze layer 33 is 5 to 10 μm and the thickness of the second glaze layer 35 is 11 to 30 μm, the surface roughness and printing characteristics are excellent. It can be seen that it has characteristics. Further, in Samples Nos. 1 and 2, density unevenness occurred in the printing characteristics because the surface was uneven. Further, in Sample No. 9, the second glaze layer 35 was thicker than 30 μm, so that bleeding and tailing occurred.

In this embodiment, the second glaze layer 35 has a thickness of 2
Although the case where the present invention is applied to a glaze substrate having a layer structure has been described, it goes without saying that the second glaze layer may have a one-layer structure or a three-layer structure or more.

Further, the case has been described where the second glaze layer 35 can be clearly distinguished into two layers even after firing, but there are cases where the two layers cannot be clearly distinguished.

[0031]

According to the glaze substrate of the present invention, a first glaze layer including a large number of pores having an average diameter of 5 to 10 μm is formed on an insulating substrate, and a layer made of glass is formed on the surface of the first glaze layer. A dense second glaze layer having a thickness of 11 to 30 μm is formed, and the second glaze layer smoothes the surface of the lower glaze layer that prevents movement of pores from the first glaze layer and the surface of the second glaze layer. By having a glaze upper layer that can be used, the smoothness of the glaze layer surface can be ensured, and the thermal conductivity of the glaze layer can be reduced, greatly improving printing efficiency and greatly reducing power consumption. The obtained glaze substrate having good printing characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a glaze substrate of the present invention.

FIG. 2 is a sectional view showing a conventional thermal head.

[Explanation of symbols]

 31 Insulating base 33 First glaze layer 35 Second glaze layer 37 Lower glaze layer 39 Upper glaze layer

Claims (1)

(57) [Claims] 1. A first glaze layer including a large number of pores having an average diameter of 5 to 10 μm is formed on an insulating substrate, and a glass layer having a thickness of 11 to 30 is formed on the surface of the first glaze layer.
a second glaze layer, wherein the second glaze layer has a dense second glaze layer, and the second glaze layer has a lower glaze layer for preventing movement of pores from the first glaze layer, and a glaze layer for smoothing the surface of the second glaze layer. A glaze substrate having an upper layer.