JPS61287765A - Thermal printing head - Google Patents

Abstract

PURPOSE:To enable to suppress a heat-releasing action of lead electrodes, to enhance printing quality and to reduce manufacturing cost, by constituting the lead electrodes or the like of a gold base conductor in a thickness of not more than 1mum. CONSTITUTION:The lead electrodes 60 provided between a driving circuit and heating resistors 3 and the lead electrodes 70 provided between a common electrode 5 and the resistors 3 are opposedly provided on opposite sides of the the resistors 3. The connecting parts of the electrodes 60, 70 and the resistors 3 are arranged in a comb-tooth form so as to intersect alternately with each other. The lead electrodes 60, 70 are formed from a gold paste consisting of a mixture of particulate gold and a resin, and the thickness thereof is set to be about 0.5-1mum. Accordingly, the head-releasing action of the conductor can be suppressed, a glaze layer is made thinner, the heating resistors can be printed in the fine patterns through the reduction in the thickness of the conductor, the printing quality can be enhanced through reduced scatter of the resistance value of the conductors, and the manufacturing cost can be reduced through a reduction in the amount of the gold paste used.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a thermal print head used in a thermal type or thermal transfer type printer.

<Prior Art> Generally, this type of thermal printing head includes one shown in the plan view of FIG. 6, for example.

In the figure, reference numeral 1 denotes an insulating substrate, and a glaze layer 2 (see FIG. 7) is formed on one surface of this insulating substrate, and a heating resistor 3 is formed through this glaze layer 2. There is. The heat generating resistor 3 is composed of a continuous strip resistor, and is individually connected to the drive circuit 4 and the common electrode 5 for each printed dot. This drive circuit 4 controls energization of the heating resistor 3 for each printed dot based on a control signal, and is mounted on an insulating substrate l. An insulating substrate l is provided between this drive circuit, the common electrode 5, and the heating resistor 3, respectively.
They are connected by a plurality of lead electrodes 6.7 formed above.

As shown in FIG. 7, a thermal print head having such a configuration usually prints a glaze layer 2 to a predetermined thickness on one surface of the insulating substrate l, and then bakes the glaze layer 2 and the insulating substrate l. Over the top, each lead electrode 6.7 is printed and fired two to three times using a screen printing method, and then
Finally, the heat generating resistor 3 is formed to have a thickness of 2 μπ to 6 μm, and the heat generating resistor 3 is formed across the end of the lead electrode 6°7.
Print.

It is being fired.

<Problems to be Solved by the Invention> Conventionally, the lead electrodes 6 and 7 are made of gold (A
U) is made of a conductive material whose main component is, for example, a gold paste made by mixing gold with a resin, but in this case, there are the following problems.

That is, when such a thermal printing head is driven, the surface temperature of the heat generating resistor 3 is normally kept at 300°C to 5°C.
Although it is necessary to raise the temperature to about 00° C., the thicker lead electrodes 6.7 also have a correspondingly greater heat dissipation effect. For this reason, conventionally, in order to prevent the heat dissipation effect of the lead electrodes 6.7 from affecting the driving of the heating resistor 3, the thickness of the glaze layer had to be increased.

Also, if the lead electrodes 6 and 7 are thick like this,
As shown in FIG. 7, unevenness occurs on the surface of the heating resistor 3 due to the dripping of the lead electrodes 6 and 7. Therefore, as shown in FIG. 8, the heating resistor 3
Bleeding occurs in the portion sandwiched between the lead electrodes 6 and 7, resulting in a problem with printing quality.

Furthermore, as the thickness of the lead electrode 6.7 increases, the amount of gold paste used increases, resulting in a problem in that the manufacturing cost increases.

The present invention was made in order to eliminate such conventional problems, and suppresses the heat dissipation effect of the lead electrode, as well as
The purpose is to improve printing quality and reduce manufacturing costs.

<Means for Solving the Problems> In order to achieve the above object, the present invention is characterized by a structure in which lead electrodes and the like are made of a gold-based conductor and have a thickness of 1 μm or less.

<Example> Hereinafter, the present invention will be described in detail based on an example shown in the drawings. The thermal printing head of this embodiment has almost the same configuration as the conventional thermal printing head shown in FIG. Omitted.

FIG. 1 is an enlarged plan view of the main part of this embodiment, FIG. 2 is a sectional view taken along the cutting line -H in FIG. 1, and FIG.
The figure is a sectional view taken along cutting line lll-H in FIG. 2. In these figures, a lead electrode 60 is wired between the drive circuit (not shown) and the heat generating resistor 3, and a lead electrode 7 is wired between the common electrode 5 and the heat generating resistor 3.
0 are arranged opposite to each other with the heating resistor 3 in between, and the connecting portions of both lead electrodes 60 and 70 with the heating resistor 3 are arranged in a comb-teeth shape in an alternately intersecting state. .

Each of the lead electrodes 60 and 70 is made of a gold paste made by mixing resin into particulate gold, and the thickness thereof is set to about 0.5 to 1 μm.

Therefore, since the thickness of each lead electrode 60, 70 is only 172 mm or less compared to the conventional example, the heat dissipation effect on the heating resistor 3 is suppressed.

Therefore, when forming the glaze layer 2 that acts as a heat storage layer, its thickness can be reduced.

Furthermore, since the heating resistor 3 is formed on the lead electrode 60.70, as shown in FIG. As the lead electrode 6' bulges further, some bleeding will occur during printing, but in this regard as well, the lead electrode 6'
Since the thickness of 0.70 is small, unevenness that affects printing quality does not occur. Furthermore, the amount of gold used decreases as the thickness decreases.

In this embodiment, each of the lead electrodes 60 and 70 is made of gold paste, but if the gold paste is printed and fired only once on the insulating substrate l using a general screen printing method, Due to its material properties, gold sintering progresses first and aggregates in the paste, for example, as shown in Figure 4, a portion A where gold is unevenly distributed at a high density in the lead electrode 60, 70 (see Figure 4). , indicated by diagonal lines) and areas where gold is sparse,
A so-called skid portion B is formed. If such a gap B exists, the resistance value of the lead electrodes 60 and 70 will inevitably increase, and depending on how wide the gap B is, there will be a problem of wire breakage.

FIG. 5 is a longitudinal sectional view of another embodiment of the invention.

In this embodiment, in order to eliminate the above-mentioned problem, each lead electrode 61, 71 is formed using a gold plate supporting layer 8a.

8b and organic gold paste layers 9a and 9b are layered to form a two-layer structure.

That is, when forming the lead electrodes 61, 7] by the screen printing method, gold paste layers 8a, 8b are first printed and fired on the insulating substrate 1 and the glaze layer 2. This gold paste is a common one having the same composition as in the previous example. Next, this gold paste layer 8a,
After leveling 8b, drying and hardening, the organic gold paste layers 9a and 9b are superimposed on the gold paste layers 8a and 8b, printed and fired, and leveling treatment is performed in the same manner. After that, dry and harden. This organic gold paste is an organic compound in which a gold component and a resin component are combined at the molecular level, and due to its material properties, even if it is formed into an extremely thin layer, gold will not be unevenly distributed and a dense electrode layer can be obtained.

As this organic gold paste, for example, "Metal Auger
Product name) etc. are preferred.

As described above, in this embodiment, a thin electrode layer of 1 μm or less can be formed without producing any blemish portion B using a general screen printing method. Note that the gold paste layer 8
a, 8h and organic gold paste layer 9a.

The vertical arrangement relationship with 9b may be reversed.

In addition, according to each of the above-mentioned Examples, it has been found that it is possible to reduce the manufacturing cost by about 50% by reducing the gold content. Furthermore, the variation in resistance value of the lead electrodes 60.70 was also suppressed to ±15%.

<Effects of the Invention> As described above, according to the present invention, since the thickness of the current-carrying conductor connected to the heating resistor is set to 1 μm or less, the heat dissipation effect of the conductor can be suppressed. For those having this, the thickness can be made thinner. Furthermore, by making the conductor thinner, the printed pattern of the heating resistor becomes a fine pattern, suppressing variations in resistance value, and improving printing quality. Furthermore, since the amount of expensive gold paste used is reduced, it has become possible to significantly reduce manufacturing costs.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is an enlarged plan view of the main part of this embodiment, FIG. 2 is a sectional view taken along the cutting line -H in FIG. The figure is a sectional view taken along the cutting line ■-■ in FIG. 2, FIG. 4 is a partially taken-out plan view showing an inconvenient formation of the lead electrode, and FIG. 5 is a longitudinal sectional view of another embodiment of the present invention. , FIG. 6 is a plan view of a general thermal printing head, FIG. 7 is a vertical cross-sectional view of a main part of a conventional example, and FIG. 8 is a cross-sectional view taken along the cutting line ``---'' in FIG. 7. ■・・・Insulating substrate 1. 2... Glaze layer, 3... Heat generating resistor, 60.61, 70.71... Lead electrode (conductor), 8
a, 8 b...gold paste layer, 9 a, 9 b
...Organic gold paste layer.

Claims (1)

[Claims] (1) A thermal printing head comprising a heating resistor and a current-carrying conductor connected to the heating resistor, wherein the conductor is composed of a conductor layer containing gold as a main component and having a layer thickness of 1 μm or less.