JPS61189955A - End surface type thermal head - Google Patents

Abstract

PURPOSE:To obtain a good heat dissipation property and to increase the degree of freedom in common electrode processing, by forming a glass layer so as to expose one end surface of a metal layer and a part on one main plane. CONSTITUTION:A metal layer having m.p. of 800 deg.C or more is provided so as to be continued to one end surface 71, provided with a heat generator, of an electric insulating flat Al2O3 plate 70 and one main plane 72, to which a separation electrode is formed, of said flat plate 70 and a glass glaze layer 76 is formed to the aforementioned metal layer so as to expose a part on the aforementioned one end surface 71 of the metal layer having a m.p. of 800 deg.C or more and a part on the aforementioned main plane 72. By this constitution, a common electrode 78 is electrically connected to the metal layer 73 on the end surface 71 through the exposed part 74 thereof and, by this structure, can be taken out through the exposed part 75 of the metal layer 73 on the main plane 72 to which the separation electrode 79 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The thermal recording method is easy to maintain and is therefore used as printers for many terminals including facsimile machines. Furthermore, in recent years, a thermal transfer recording system has been developed, and multicolor recording (b) has become capable of full-color recording, and is being developed as a new recording device.

The present invention provides a thermal head that is particularly useful in a thermal transfer system that enables multi-color or full-color recording.
Specifically, the present invention relates to an end face type thermal head in which a large number of heat generating elements are formed in a line on the end face of a heat generating element substrate.

The conventional thermal recording method is applied to various terminal printers as a recording method that is easy to maintain. In particular, recently, in addition to the conventional color-forming heat-sensitive recording method, a transfer-type heat-sensitive recording method has been developed, and full-color recording has become possible with this method.

When performing color recording using a thermal transfer recording method, one of the biggest differences from monochrome recording using a conventional color-forming recording method is the problem of color shift during overlay. FIG. 4 shows the relationship between a thermal head and recording paper used in conventional monochrome recording.

In FIG. 4, 1& is an image receiving paper, 1b is a transfer paper, 2 is a paper feeding roller, and 3 is a thermal head.
Since the heating element array 3b is formed, this type of head will be referred to as a planar thermal head hereinafter.

In FIG. 4, the paper feed roller 2 transfers the transfer paper 1b.

When the image receiving paper 1a is brought into pressure contact with the heating element row 3b of the thermal head 3 and being fed in the direction of the arrow, the heating element row 3b is energized and heated in accordance with the image signal, monochromatic recording can be performed on the image receiving paper 11L.

In FIG. 4, if direct coloring type thermal recording paper is used instead of 1a and 1b, a recording section of a normal thermal recording system is formed. On the other hand, in a thermal head using the substrate of the present invention, a recording section is formed in the form shown in FIG. In FIG. 5, the thermal head 6 has one surface (end surface) of four surfaces parallel to the thickness direction of the heating element substrate 6a.
A heating element row 6b is formed in the heating element row 6b. Below, the fifth
The head with the configuration shown in the figure is called an end-face type thermal head.

As can be seen from a comparison between FIG. 4 and FIG. 5, in the monochrome thermal transfer recording method, the recording state can be seen more quickly in FIG. 4.

Color recording is possible with the thermal transfer recording method.

FIG. 6 shows a method of configuring a recording section having a simple device configuration as a color printer.

In FIG. 6, the image receiving paper 11& is fixed by being wrapped around the paper feed roller 2, and in this state, the image receiving paper 12L is pressed against the heating element row of the thermal head 5 via the transfer paper 1b, and as the roller rotates, the transfer paper Send 1b in the direction of the arrow. Cyan 11b is on the transfer paper 1b.

Magenta 12b, yellow 13b, and black 14b are applied to the outer periphery of the paper feed roller as a unit length (uniformly for each color within this unit length range). Therefore, each rotation of the paper feed roller produces cyan.

Color recording is possible by sequential transfer printing of magenta, yellow, and black. Note that the colors applied to the transfer paper are not limited to the above-mentioned colors; other colors may be added, and black is basically synthesized from cyan, magenta, and yellow, so it is also possible to omit it. be.

Further, the order of transferring to the image receiving paper is not particularly limited.

The advantage of using image-receiving paper wrapped around a roller in this way is that the image-receiving paper returns to its initial position with each rotation of the roller, making it possible to superimpose each color with high precision, and with a simple device configuration. It is possible.

Such an apparatus configuration is also possible using the planar thermal head shown in FIG. However, in this recording method, the roller is larger than in conventional monochrome transfer recording or thermal recording methods. For this reason, it is necessary to increase the size of the head itself, which significantly increases the price of the head.

On the other hand, in the end face type thermal head shown in FIG.
It is possible to use heads of the same shape, including the device configuration shown in the figure, making it possible to mass-produce heads and reduce costs. As described above, it is clear that the edge type thermal head is especially advantageous in the thermal transfer recording system.

However, most conventional thermal recording has been performed using a flat head. This is 1. This is because flat heads are generally considered easier to manufacture.

A thermal head with a heating element on the end face is a thermal hept, in which a row of heating elements is formed on the end face of a rectangular semiconductor silicon plate using a diffusion method, or a row of heating elements is formed on the surface of a round glass rod parallel to the central axis. Thermal heads etc. are also made.

FIG. 7 shows an example of the appearance of an end face type thermal head. 7th
In the figure, 7 is a heating element substrate, which has a plate-like shape in this figure. A heating element row 8 in which a large number of heating elements are arranged in a row is formed on one end surface of this rectangular substrate 7. The heating element board 7 is connected with a screw 11 between the head base 9 and the cover 10.
Terminals for driving each heating element of the heating element row 8 are taken out by the film lead 12 from an electrode part (not shown) extending and formed on the side surface 7a of the heating element substrate, and then soldered. The attachment is led to a connector 14 via a portion 13.

The method of electrically connecting the electrode portion extending from the heating element row 8 to the side surface 7 to the connector 14 is performed by connecting a semiconductor element connected to the heating element, such as a diode, a thyristor, a shift register, a latch, or a transistor. The appearance of the head varies depending on which IC or the like having a driver circuit is used, and the appearance of the head changes accordingly.

A thermal head shown in FIG. 7 constructed of semiconductor silicon or glass round rod as a substrate is hardly used for thermal transfer recording. The main reason for this is the substrate that forms the heating element rows for both thermal heads.

In other words, in heads that use semiconductor silicon, the heating resistor part and the silicon substrate are not thermally separated, so more heat flows out to the substrate than is transferred to the paper, and therefore the thermal efficiency is extremely low. . On the other hand, in a head using a glass round rod, the thermal conductivity of the glass substrate is low, and therefore heat easily accumulates on the substrate, making it difficult to perform halftone printing at high speed. Furthermore, since the round bar is made of glass, it is difficult to fix it to a base and to mount an IC having a driver circuit.

As described above, heads using semiconductor silicon or glass round rods as substrates have problems in terms of high-speed printing and thermal efficiency. In order to solve these problems, a head using a rectangular substrate with glass layers formed on the end and side surfaces of the substrate as shown in FIG. 8 has also been proposed. In FIG. 8, 512L and 61b are glass layers having a lower thermal conductivity than the substrate material, and are continuously formed on the end surface portion 1512L and the side surface portion 61b. 62 is an insulating material mainly made of aluminum. FIG. 9 shows the structure of a substrate portion in which a heating element is formed using such a substrate.

In FIG. 9, 51& and 61b are glass layers, 52 is an electrically insulating material mainly composed of alumina, 61 is a heating resistor, and 62 is connected to an IC having a driver circuit for driving each heating resistor 61. 63 is a common electrode commonly connected to each heating resistor 61, 64 is a plated conductor plated on the common electrode 63, and 66 is an abrasion-resistant protective film for protecting the heating element part from wear. be. In addition,
Although the wear-resistant protective film 66 is formed on the entire heating element part, in consideration of the ease of explanation of the figure, a part of the film is not formed.

In this substrate, the heat generated by the heating element is thermally insulated by the glass layer, so as soon as it is transmitted to the recording paper side, the thermal efficiency is improved. On the other hand, regarding the substrate part, compared to glass round rods, a substrate mainly composed of alumina has better thermal conductivity and improved heat dissipation. Actually, using a board as shown in Figure 9,
When an end face type head as shown in Fig. 7 is constructed,
Even when printing was performed using sublimation transfer paper at a printing cycle of about 30 m5ec/1ine, it had sufficient heat dissipation.

However, even in the thermal transfer recording system, there is a strong demand for high-speed printing, and the substrate configuration shown in FIG. 8 could not meet this demand. The reason for this is as follows.

FIG. 7 shows the assembly configuration of the edge type gutter. Excess heat generated by the heating element 8 after printing is transmitted to the base 9 through the substrate 7 and radiated into the atmosphere.

Of course, some of the heat is transmitted to the cover 10 and radiated into the atmosphere, but most of the heat is transmitted through the base. The heat generated in the heating element section therefore flows into the base section through a relatively long distance of the substrate section. This indicates that the quality of the thermal conductivity of the substrate itself has a significant effect on heat dissipation.

For this reason, it is necessary to use a substrate with better thermal conductivity than a substrate mainly composed of alumina in order to enable high-speed printing. Materials with higher thermal conductivity than alumina include ceramics, silicon carbide,
There is aluminum nitride.

However, beryllia is rarely produced at present due to its toxicity. Although silicon carbide is widely used for various purposes, it is difficult to process the molds used in thermal heads due to its high hardness.

Furthermore, although aluminum nitride is more expensive than aluminum, its thermal conductivity is not very high. As described above, it has not been possible to obtain a substrate material with good thermal conductivity. Therefore, in order to improve heat dissipation using conventional alumina, it is considered effective to increase the thickness of the plated conductor 64 plated on the common electrode part in FIG. 9 to about 20 to 30 μm, for example. It was done. This is effective in that it can increase the degree of freedom in processing the common electrode, such as reducing the number of locations for attaching lead wires from the common electrode in addition to heat dissipation. 3
0 μm requires several hours and is not suitable for mass production, and in addition, the heat transfer path from the heat generating part to this plating layer 64 essentially passes through a layer of a low thermal conductive material such as substrate alumina, so the heat there is The muffle still exists.

Further, FIGS. 10a and 10b show an example of the processing state of the head base 9 in the assembled configuration shown in FIG. 7. Figure 10 shows the patent application filed in 1983.
In the example of No. 128305, as shown in FIG.

The flat surface forming the common electrode of the end-face type thermal head substrate is adhered to the flat surface 67 of the head base 9 via a sheet-like adhesive layer. FIG. 10 shows a lead-out line 68 from the common electrode, which is embedded in the processed groove 66 and connected to the common electrode of the end-face type thermal head substrate through a projection 69. Such a common electrode processing method requires processing of the head base, leading to an increase in cost. Furthermore, the sheet-like adhesive layer used for adhering the flat surface 67 of the head base 9 and the end-face type thermal head substrate is
Only electrically insulating materials are used, which has a small degree of freedom, and this becomes a heat storage layer, making it difficult to smoothly dissipate heat from the substrate to the head base.

Problems to be Solved by the Invention As described above, with the configuration of the conventional edge-type thermal head substrate, it is difficult to obtain good heat dissipation required for high-speed printing. In addition, (1) production costs increase, (2)
) Problems such as a decrease in the degree of freedom in common electrode processing occurred.

The present invention has been made in view of these points, and provides an end face type thermal head that has a simple configuration, has good heat dissipation properties, and improves (1) or (2).

Means to solve problems The present invention aims to solve these problems.

(1) A layer made of a metal having a melting point of 800°C or more is provided continuously on one end face of the electrically insulating flat plate on which the heating element is provided and on the flat surface forming the separation electrode, and the metal having a melting point of 800°C or more is provided. said 8 to expose a part on said one end surface of the layer consisting of
A substrate is formed by forming a glass layer on a layer of metal having a melting point of 00°C or higher, or (2) a flat surface on which a common electrode is formed with one end surface of an electrically insulating flat plate on which a heating element is provided. A continuous layer of metal having a melting point of 800°C or higher is provided, and at least the layer of metal having a melting point of 800°C or higher of the one main plane soil is exposed. The substrate is constructed by forming a glass layer on top of the glass layer.

Function: In the configuration of these end face type thermal heads, (1)
Then, in the exposed part on one end surface where a heating element of a layer made of a metal having a melting point of more than AOO'C is provided, an electrode is later connected and formed on a glass layer, thereby forming a separate electrode on a flat surface. The exposed metal layer with a melting point of 800° C. or more can be used as a common electrode, and therefore, the separation electrode and the common electrode can be simultaneously exposed on the flat surface forming the separation electrode, which facilitates common electrode processing. In addition, heat dissipation can be improved by the presence of a metal layer having a melting point of aOO°C or higher that is continuous from one end surface on which the heating element is provided to the life plane that forms the separation electrode, and at the same time, the metal layer that faces the life plane that forms the separation electrode can be improved. When attaching a flat surface to the head base, there is no need to create a processing groove for attaching the common electrode lead wire on the base, reducing costs. is a good electrical conductor)
can be used, and heat dissipation can be improved in this aspect as well.

On the other hand, in (2), it is possible to use the metal layer with a melting point of 800°C or more formed on the flat surface that forms the common electrode as it is as the common electrode, and there is no need for thick film plating as in the past. In addition to reducing costs,
Heat dissipation can be improved by the continuous metal layer having a melting point of SOO° C. or higher extending over the entire plane from one end surface where the heating element is provided to the common electrode.

Embodiment FIG. 1 shows a substrate structure of an end face type thermal head as an embodiment of the present invention. Here, we will talk about figure a,
b will be described later.

As shown in Figure 1, AA2o3 has electrical insulation properties.
A metal layer 73 is continuously formed on the end face 71 forming the heating element and the life plane 72 forming the separation electrode of the flat plate 7o. Glass glaze layer 7 is left exposed on the top part.
form 6.

74 and 76 are exposed parts. At this time, since the glass glaze layer 76 is usually fired at a temperature of 800°C or higher, a metal that does not react with the glass glaze layer 76 at this temperature is, for example, M-Pd (melting point 1063°C). (
The metal layer 73
After forming a thick film (several tens of μm) and firing the glass glaze layer 76, it was confirmed that good insulation was obtained on the glass glaze layer 76. Using this substrate, the state after actually forming the heating element and electrodes is shown in the second figure.
As shown in the figure.

As is clear from the figure, a heating element array 77 is formed on the end face 71, and a common electrode 78 and a separation electrode 79 for supplying electricity to the heating element array 77 are formed on the end face 71 and the lifetime plane 72. No electrodes are formed on the other main plane 8o. In this configuration, the common electrode 78 is electrically connected at the exposed portion 4 of the metal layer 73 on the end surface 71 and thereby at the exposed portion 75 of the metal layer 73 on the main plane 72 forming the separation electrode 79. The common electrode can be taken out. According to this, since the separation electrode and the common electrode can be taken out on the main plane 72, when the main plane 8o on which no other electrodes are formed is attached to the head base via a sheet-like adhesive layer, the conventional end surface When a common electrode is formed on the main plane 80 as in the type thermal head, there is no problem such as the presence of protrusions that break through the sheet-like adhesive layer and prevent electrical insulation. The range of selection becomes wider. In addition, the sheet-like adhesive layer may be made of a good thermal conductor (generally a metal that is a good electrical conductor), for example,
It is possible to bond using adhesive paste etc.
Heat dissipation to the base can be improved. In addition, the first
There is no need to process the head base as shown in Figure 0.
It becomes possible to reduce costs.

As shown in FIG. 1, a metal layer 84 is continuously formed from the end face 82 of the flat plate 81 forming the heating element to the life plane 83 forming the common electrode, and the life plane forming the common electrode. A glass glaze layer 85 is formed on the metal layer 84 on the end face 82 forming the heating element while the metal layer 83 is left exposed.

At this time, for the same reason as in the above embodiment, the metal layer 84 is made of, for example, λg-Pd, and a thick film (several tens of μm
), and after firing and forming the glass glaze layer 85, it was confirmed that good insulation could be obtained on the glass glaze layer 85. FIG. 3 shows the state after actually forming heating elements and electrodes using this substrate.

As shown in the figure, in order to energize the heating element row 86 formed on the end surface 82 of the human β 203 flat plate, a common electrode 88 is provided on the end surface 82 and the negative main plane 87, with a part extending to the main plane 83. By forming a separation electrode 89 and electrically connecting the common electrode 88 and the metal layer 84 on the flat surface 83 as shown in 90, the metal layer 84 can be used as a common electrode, and the metal layer 84 can be used as a common electrode. A common electrode can be used without thick film plating, reducing costs. Furthermore, the metal layer 84, which is continuous from the end face 82 forming the heating element to the lifetime plane 83 forming the common electrode, can effectively configure a heat radiation path in the substrate, and improve heat radiation performance.

As described above, according to the edge-type thermal head of the present invention, it is possible to easily obtain good heat dissipation properties necessary for high-speed printing, and to reduce production costs. The embodiment shown above has high industrial utility value, such as increased freedom in processing the common electrode. In the present example, the metal layer 73.84 was made of U and Mug-Pd, but other metals may also be used, which have a melting point higher than the firing temperature of glass (8oO°C) and do not react with glass. A similar effect can be obtained by using .

As described above, the edge-type thermal head according to the present invention can easily obtain good heat dissipation properties necessary for high-speed printing, and can reduce production costs. In the case of claim 11, the degree of freedom in processing the common electrode is increased, and the industrial value is great.

[Brief explanation of the drawing]

FIGS. 1a and 1b are cross-sectional views showing the structure of a substrate of an edge-type thermal head according to an embodiment of the present invention, and FIGS.
The figures are a perspective view and a cross-sectional view showing an example of the configuration of a thermal head after pattern formation using this substrate, and Figures 4 to 10 are diagrams for explaining conventional thermal head technology. FIG. 2 is a schematic diagram and a perspective view. 70.81...Mu J20s flat plate, 71.82.
... End face, 72.83 ... Main plane on common electrode forming side, 73°84 ... Metal layer having melting point of 800° C. or higher, 74', 75 ... ...Exposed part, 7
6.85...Glass glaze layer. Name of agent: Patent attorney Toshio Nakao and one other name
! @ 74 Ujidebe Figure 4? -T” Figure 5 Figure 10/A)

Claims (2)

[Claims] (1) A layer made of a metal having a melting point of 800°C or higher is provided continuously on one end face of the electrically insulating flat plate on which the heating element is provided and on one main plane forming the separation electrode, and at least the above 8
A heat conductor smaller than that of the electrically insulating flat plate is formed on the layer made of a metal having a melting point of 00° C. or more so as to expose a portion on the one end surface of this layer and a portion of the one main plane soil. 1. An end-face type thermal head, characterized in that a substrate is formed by forming a glass layer having a high temperature. (2) A layer made of a metal having a melting point of 800°C or more is provided continuously on one end face of the electrically insulating flat plate on which the heating element is provided and on the one main plane forming the common electrode, and at least 800°C of the one main plane soil is provided. The substrate is characterized in that a glass layer having a thermal conductivity lower than that of the electrically insulating flat plate is formed on the layer on the one end surface so as to expose a layer made of a metal having a melting point of ℃ or more. Edge type thermal head.