JPH10138542A - Thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal head made easy in the connection with a set by miniaturization. SOLUTION: In a thermal head wherein heating resistors 6 and a plurality of drive ICs 9 are provided on a rectangular insulating substrate 1 in the longitudinal direction of the substrate 1, the arranging length of a plurality of the drive ICs is set to a region shorter than the effective printing width length of the heating resistors 6 and an external connection terminal group 14 is collectively arranged to the empty space formed to the end part of either one of the long sides of the insulating substrate 1. Ground electrodes 15 are arranged on the insulating films provided on the individual electrodes 8 led out of the heating resistors 6 to be respectively connected to a plurality of the drive ICs 9 along the longitudinal direction of the insulating substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermal head.

[0002]

2. Description of the Related Art As an example of a conventional thermal head, for example, a thermal head proposed in Japanese Patent Application Laid-Open No. Hei 5-84852 is disclosed in Japanese Patent Application Laid-Open No. 5-84852, on a surface of a rectangular insulating substrate in parallel with one long side of the insulating substrate. A print medium, for example, a heating resistor is arranged, and a plurality of drive ICs for driving the heating resistor for every predetermined number of dots are arranged and mounted along a straight line parallel to the arrangement direction of the heating resistor.

On the other hand, a plurality of external connection terminals for connection to an external control circuit are formed on the other long side of the insulating substrate, and the plurality of drive ICs are shorter than the arrangement length of the heating resistors. The external connection terminals are intensively arranged at both ends in the longitudinal direction of the insulating substrate, which has a space allowance.

Further, one or both ends of the external connection terminals are electrically connected to a part of the external connection terminal in a band-shaped region extending from the mounting portion of the drive IC on the insulating substrate to the other long side of the insulating substrate. Are formed, and a predetermined signal input pad of each drive IC is commonly connected to the signal wiring pattern.

In the thermal head, since external connection terminals are concentrated on both ends in the longitudinal direction of the insulating substrate, the length from the connection terminal of the common wiring to the supply portion to each heating resistor can be shortened. And the print quality can be improved. This means that, similarly to the common wiring, the ground wiring is commonly connected from the external connection terminals to the respective drive ICs for driving the dots of the heating resistor, so that if the external connection terminals are arranged at both ends of the insulating substrate, The length of both the common wiring and the ground wiring can be reduced, and the voltage drop can be reduced.

[0006] As another example of a conventionally proposed thermal head, for example, a thermal head proposed in Japanese Patent Application Laid-Open No. H5-177863 discloses a thermal head in which a heating resistor and a driving IC are formed on a rectangular insulating substrate. And a signal wiring for commonly connecting the control signal pads of the respective drive ICs with individual electrodes for connecting the heating resistor and the drive IC on the insulating substrate. A pattern is formed.

A ground electrode is formed along an edge of a long side opposite to the side on which the heating resistor is disposed with reference to the mounting portion of the drive IC, and the ground electrode is connected to the drive IC. The signal wiring pattern is disposed therebetween.

In the thermal head, the width of the ground electrode can be increased or decreased by forming the ground electrode along the edge of one long side of the rectangular insulating substrate. A large current can flow.

Further, as another example of the conventionally proposed thermal head, for example, a thermal head proposed in Japanese Patent Publication No. 7-12702 is provided on a rectangular insulated substrate with one long side of the insulated substrate. A heating resistor is arranged in parallel with the side, and a plurality of drive ICs for driving the heating resistor for every predetermined number of dots are arranged and mounted along a straight line parallel to the arrangement direction of the heating resistor.

[0010] Each input of each drive IC provided on the insulating substrate, such as a plurality of signal wirings, such as a signal-in terminal, a power supply terminal, a clock signal terminal, a ground terminal, a latch terminal, a strobe terminal, and a signal-out terminal. The signal wiring terminals are connected to the common signal line by wire bonding.

These common signal lines are arranged between a ground electrode pattern formed along the other long side and a plurality of drive IC rows, and are connected to the common electrode at the other long side end of the insulating substrate. The pattern and the ground electrode pattern are formed along the tip, and only the strobe pattern in the pattern is linearly arranged so as to pass under each drive IC.

[0012]

However, the thermal head proposed in Japanese Patent Application Laid-Open No. Hei 5-17763 is
Forming a wide ground electrode on an insulating substrate
Inevitably, the width of the short side of the insulating substrate itself is increased, which is an obstacle to miniaturization. In addition, the ground electrode is formed along the edge of the long side opposite to the side on which the heating resistor on the insulating substrate is arranged, but the space on the insulating substrate at that portion is only the ground electrode. is there. In such a configuration, for example, even if the signal wiring pattern and the ground electrode are superposed, only the space between the driving IC and the ground electrode and the space under the mounting of the driving IC are left, which does not contribute to space saving. .

As described above, Japanese Patent Application Laid-Open No.
In the thermal head proposed in Japanese Patent Application Laid-Open Publication No. H11-139, a part of the space on the insulating substrate is allocated only to the ground electrode, which causes the width of the insulating substrate itself to be increased. The present invention has been made in view of the above problems, and an object of the present invention is to provide a thermal head that can be reduced in size by increasing the width of a ground electrode pattern while suppressing an increase in the width of an insulating substrate.

When a thermal head proposed in Japanese Patent Application Laid-Open No. 5-84852, in which external connection terminals are arranged at both ends of an insulating substrate, is incorporated in a set such as a facsimile, a signal for driving the thermal head is output. It is necessary to connect the control board on the set side, the power supply board for supplying a power supply voltage for driving, for example, 24 V, and the thermal head substrate.

In general, on the set side, the power supply board or the control board is commonly used for several types of facsimile reset models, so that it is versatile. Is being done. Therefore, connection terminals for connecting the thermal head substrate to the power supply substrate and the control substrate are provided independently.

When the thermal head substrate having the above structure is electrically connected to the set, connection cables are attached to the external connection terminals on both sides of the thermal head. Power supply terminals and control signal terminals are respectively provided in the external connection terminals on both sides. Therefore, at the set side end of the connection cable, it is necessary to branch off for the power supply board connection terminal and for the control board connection terminal, and to attach two connectors to the end. For this reason, in the thermal head substrate having the above-described structure, when the thermal head substrate is incorporated into a set, two cables whose ends are branched into two systems are required.

Further, a cable with a branched end has a special specification, which increases the manufacturing cost of the cable and affects the price of the printer set. Therefore, when using a standard specification cable that does not branch off, the power supply board connection terminal and control board connection terminal for connecting to the thermal head board on the set side must be centrally arranged in one place This also increases the manufacturing cost on the set side.

Further, when the external connection terminals are arranged in a concentrated manner as in the prior art, a ground electrode commonly connected from the ground terminal of the external connection terminal to the ground terminal of each drive IC is opposite to the drive IC row with respect to the heating resistor. Must be arranged along the edge of the longer side of the insulating substrate. Furthermore, the ground electrode needs a current capacity corresponding to the number of dots of the heating resistor to be printed at the same time.
A current capacity of about 6 A is required.

In order to obtain a ground electrode pattern having such a current capacity, a pattern width of about 1 mm is required. If such a ground electrode is newly added on the insulating substrate, the shortness of the insulating substrate is reduced. The hand size will increase accordingly.

Further, in the thermal head proposed in Japanese Patent Publication No. 7-12702, a plurality of signal wirings other than a strobe pattern are arranged between a driving IC row and a ground electrode, and an input of the driving IC is provided. Each is connected to a signal terminal. In such a configuration, in order to wire-bond the input signal terminal of the driving IC and each signal wiring, a distance between the driving IC and the signal wiring pad is required, and an arrangement area for a plurality of signal wirings is required. From that
It is difficult to reduce the size of the insulating substrate in the short side direction.

Further, in view of the above problems, the present invention reduces the number of electrical connections between the thermal head and the set side,
Moreover, even when independently connected to the connection terminals of the power supply board and the control board on the set side, the cables can be easily separated and divided, and the problem of the arrangement of the plurality of signal wirings can be solved.
A thermal head for shortening an insulating substrate is proposed.

[0022]

[MEANS FOR SOLVING THE PROBLEMS] On a rectangular insulating substrate,
In a thermal head having a heating resistor arranged in the longitudinal direction of the insulating substrate and a plurality of driving ICs arranged in the longitudinal direction on the insulating substrate, the length of the plurality of driving ICs is determined by the heating resistor. A thermal head is arranged in an area shorter than the effective print width of the body, and external connection terminals are intensively arranged in an empty space formed at one end of the long side of the insulating substrate. . In addition, a ground electrode is provided on the insulating film provided on the individual electrode connected to the driving IC and led out from the heating resistor along the longitudinal direction of the insulating substrate.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an overall plan of an embodiment of a thermal head according to the present invention will be described with reference to FIG. FIG.
As shown in FIG. 2, a heating resistor 6 is formed on a glaze layer (not shown) provided on a rectangular insulating substrate 1 on the first long side 2 side thereof in parallel with the first long side. Between the heating resistor 6 and the first long side 2, a second parallel to the heating resistor 6 is provided.
The common electrode 7 is formed. The first common electrode will be described later. One end of the second common electrode 7 has a common electrode extension 7a extending in a direction orthogonal to the heating resistor 6 along a first short side 4 at an end of the first long side 2. I have.

A drive IC 9 for driving each dot of the heating resistor 6 is mounted at the end of each individual electrode 8 extending from each dot of the heating resistor 6 to the second long side 3 side. It is connected to each individual electrode. As will be described later with reference to FIGS. 2 and 3, signal wirings 13 are provided below the driving ICs 9 and between the driving IC rows and the individual electrode pads. And the external connection terminal group 14 on the first short side 4 side. These external connection terminal groups 14 are connected to the main body set side by a connector, a flexible cable, or the like.

The first ground electrode 15 commonly connected to each drive IC 9 is arranged in the same direction as the heating resistor 6 between the row of mounting the driving ICs 9 and the heating resistor 6. From the first ground electrode 15, a connection electrode 22 for connecting to a second ground electrode described later extends toward the second long side 3. Further, the mounting portion of the drive IC 9 is sealed with the sealing resin 16 to form a thermal head substrate 28.

Next, the detailed pattern arrangement of the thermal head will be described with reference to the pattern arrangement diagrams of FIGS. 1, 2 and 3. First, gold is placed on the upper surface of the rectangular insulating substrate 1.
First made of metal material with low conductor resistance such as aluminum
The common electrode 17, the individual electrode 8, the second ground electrode 18, and the signal wiring 13 are formed by a photo-etching method. The first common electrode 17 is an electrode for supplying a heating current to each heating resistor dot, and is formed in a comb-like pattern (not shown) at the heating resistor 6. I have.

One end of the individual electrode 8 is formed with a comb-tooth pattern (not shown) at a portion where the heating resistor 6 is formed, and the comb-tooth pattern of the first common electrode 17 is alternately formed. Be placed. Further, the other end of the individual electrode 8 is extended to the second long side 3 away from the heating resistor 6, and supplies a current for heating to each dot of the heating resistor 6.

The second ground electrode 18 is connected to the drive I
This is a ground pattern of a current for heat generation bonded to the ground pad 19 of C9 and the wire 30.
The signal wiring 13 is a wiring for transmitting a signal for controlling the drive IC 9 for supplying a heating current to each dot of the heating resistor 6. After the formation of each of the wiring patterns, the heating resistor 6 is formed by electrically connecting the comb-like patterns of the first common electrode 17 and the individual electrodes 8 alternately.

The second common electrode 7 is formed of a metal material having a low conductor resistance, such as gold or silver, so as to partially or entirely overlap the first common electrode 17. To increase the current capacity. As a result, even when a plurality of dots are energized and printed at the same time, the voltage drop due to the common electrode can be suppressed low.

Further, the first ground electrode 15 is arranged between the row of the driving ICs 9 and the heating resistor 6. Under the first ground electrode 15, the insulating film 21 is formed with a width wider than the pattern width of the first ground electrode 15. Here, the first ground electrode 15 is a reinforcing pattern for increasing the current capacity of the entire ground electrode.

Further, under the first ground electrode 15, a protective film 20 made of amorphous glass (FIGS. 3 and 4)
The individual electrode 8 and the signal wiring 13 are arranged under the protective film 20.
Is the lower part of the drive IC 9, the row of the drive IC 9, and the individual electrode pads 11.
It is located between them.

In this portion, it is preferable that the insulating film 21 is an upper layer and the protective film 20 is formed as a lower layer thereof to form a two-layer insulating film. This is because the first ground electrode 15 is made of a silver-based metal material having a low conductor resistance. At this time, the silver-based metal material is formed by sintering at a firing temperature of about 800 ° C.
This is because if there is a layer of amorphous glass constituting 0, silver diffuses into the protective film 20 during firing from the silver film.

The cause of the diffusion of silver is that the protective film 20 has a low softening point of 750 ° C. in the layer mainly composed of amorphous glass. When firing at a high temperature of 800 ° C., the lower amorphous glass melts during firing, and silver easily penetrates into the amorphous glass.
It will spread. Further, the diffusion is caused by the protection film 20.
Diffusion proceeds to the lower electrode, for example, the gold electrode, leading to the formation of an alloy layer of gold and silver, increasing the conductor resistance value of the individual electrode 8, uneven print density, and in the worst case, the individual electrode Disconnection failure may occur.

Therefore, it is effective to provide a layer mainly composed of crystallized glass as the insulating film 21 as a diffusion preventing layer so that the diffusion of silver does not proceed to the lower layer. This crystallized glass has a softening point temperature of 800 ° C. or higher, which is higher than that of amorphous glass, and can prevent the diffusion of silver without melting even when baking silver at around 800 ° C.

As another method for preventing diffusion, if the first ground electrode 15 is made of gold which does not easily diffuse, it is not necessary to form a two-layer structure, and it is sufficient to provide the protective film 20 of amorphous glass. It is. As another diffusion prevention method, the first ground electrode may be formed by using a low-temperature firing silver paste having a temperature lower than or close to the softening point of the amorphous glass, for example, a firing temperature of 600 ° C. or lower. In this case, since the diffusion of silver is reduced, it is not necessary to form a two-layer structure in this case, but this does not prevent the adoption of the two-layer structure. However, in this case, the conductor resistance value of silver is higher than that of the silver fired at around 800 ° C. at the high temperature.

Next, the external connection terminal group 14 of the thermal head substrate 28 will be described in detail with reference to FIGS. As shown in FIG. 1, the mounting pitch P of each drive IC 9 is set shorter than the heating resistor dot number length E corresponding to the number of output bits of the drive IC 9. That is, a plurality of driving I
By arranging the wiring length of C in an area shorter than the effective printing width of the heating resistor 6, an empty space is formed at one end of the insulating substrate 1.

The external connection terminal group 14 is provided in this empty space so as not to overlap with the row in which the drive ICs 9 are mounted. As a result, the width of the short side of the insulating substrate 1 can be reduced, which leads to downsizing of the thermal head substrate.

As shown in FIG. 2, the external connection terminal group 14 has 24
A V drive voltage supply terminal (COM) 24 is arranged, and the second common electrode 7 is connected to the drive voltage supply terminal 24, and the number of terminals is arbitrarily formed according to a required current capacity. A ground (GND) terminal 25 is provided inside the drive voltage supply terminal 24.
And the first ground electrode 15 is connected.

Further, a signal terminal group 26 for controlling the driving IC is sequentially arranged toward the inside of the ground terminal 25,
The signal terminal group 26 includes signal-in (SI), strobe 1 to strobe 4 (STR1 to STR4), and latch (L
AT, a clock (CLK), a thermistor (TM), and a logic power supply (VDD). A signal wiring 13 (FIG. 2) is connected to each of these signal terminals. The signal wiring 13 is arranged below the driving IC 9 and between the driving IC and the connection pad 11 of the individual electrode 8. It is suitable. With such wiring, there is no signal wiring between the driving IC and the second ground electrode 18, so that the size of the insulating substrate 1 in the short side direction can be reduced. At this time, if necessary, a single component such as the thermistor 30 is arranged in a space near the second short side 5.

As shown in FIG. 2, since the second common electrode 7 is taken out from one short side 4 of the insulating substrate 1, one end of the effective printing width of the heating resistor 6 is connected to the long side of the insulating substrate 1. By arranging it close to the end vicinity, an empty space where the effective print width portion is not arranged is generated at the opposite long side end. If necessary patterns are arranged in this portion, the size of the insulating substrate, that is, the thermal head substrate can be further reduced. As an example, the thermistor 30 can be arranged in this space.

A drive IC 9 is mounted on an extension of the column of the external connection terminal group 14. In this case, the leftmost dot 32 of the effective printing width of the heating resistor 6 and the leftmost dot 32 for driving the same are driven. The wiring of the individual electrodes 8 to the drive IC is arranged with an inclination. The drive IC is mounted on an extension line inside the portion where the external connection terminal group 14 is arranged.

That is, the dimension from the short sides 4, 5 of the insulating substrate 1 near each of the left and right end dots in the effective print width area of the heating resistor 6 is defined as the size of one dot side, and the size of the other dot is defined as the other size. The external connection terminals 14 are concentrated on the longer side end of the insulating substrate on the side where the size is increased.

When the effective printing width portion of the conventional heating resistor is arranged symmetrically on the long side of the insulating substrate, the leftmost dot 32 moves on the extension of the heating resistor and moves to the left of the insulating substrate. Will do. On the other hand, the position of the leftmost drive IC cannot be moved to the left so as not to overlap the row of the external connection terminal group 14. Therefore, the inclination of the individual electrode connecting the leftmost dot and the driving IC becomes an acute angle. If the inclination of the individual electrode becomes acute,
Although the pitch of the electrode pattern adjacent to the individual electrode becomes narrower and it becomes difficult to form the individual electrode pattern, the pattern of the individual electrode can be easily formed because the inclination of the individual electrode does not become an acute angle according to the present invention. .

Next, the detailed pattern arrangement near the mounting portion of the drive IC 9 and the wire bonding will be described with reference to FIG. The first ground electrode 15 and the second
To connect the ground electrode 18, a connection electrode 22 extends from the first ground electrode 15 to the second ground electrode 18 through between the drive ICs 9. This connection electrode 2
Since 2 is orthogonal to the signal wiring 13 in the lower layer, the insulating film 21 is formed at a place where the connection electrode is to be formed so as to be wider than the connection electrode 22. This connection electrode 22 has at least a plurality of drive I
Although it is provided between C, it is preferable to be provided between all the driving ICs.

Since the first ground electrode 15 is formed of a thin film such as gold or silver, the connection from one side of the insulating substrate 1 has a high conductor resistance and a small current capacity. A voltage drop occurs toward the end of the insulating substrate farther from the substrate, causing a variation in print density.
If provided between them, this variation can be eliminated.

According to the ground electrode of the wiring pattern, the first ground electrode 15 can be formed in multiple layers on the insulating film 21 in a pattern having a sufficient width, while the second ground electrode 18 is formed of one drive IC. The pattern width may be as narrow as 0.3 mm, as long as there is a current capacity corresponding to the number of the drive dots. Therefore, the dimension from the drive IC of the thermal head substrate to the second long side 3 can be reduced.

As described above, the width of the thermal head substrate can be reduced, and at the same time, the drive voltage drop due to the ground electrode can be reduced to prevent the occurrence of variations in print density. And a thermal head that can be centrally arranged.

Further, when the above-mentioned wiring pattern arrangement is employed, the pads 12 provided on the short side of the driving IC 9 and the signal wiring pads 23 can be wire-bonded between the driving ICs, and the driving IC 9 row and the Only the wire bonding connection between the ground pad 19 and the second ground electrode 18 arranged near the long side of the drive IC 9 is provided between the two ground electrodes 18, and the distance between the drive IC row and the second ground electrode 18 can be reduced. It becomes possible.

Hereinafter, the multilayer wiring structure portion of the head substrate having the above wiring structure will be described with reference to the sectional views of FIGS. FIG. 4 is a detailed cross section taken along line AA ′ of FIG. The first common electrode 17, the individual electrode 8, the signal wiring 13, and the second ground electrode 18 are simultaneously formed on the insulating substrate 1 simultaneously. Then, the heating resistor 6 is formed on the individual electrode 8, and the second common electrode 7 for reducing the resistance value is stacked on the first common electrode 17. Further, a protective film 20 is formed on each of the electrodes, and a crystallized glass insulating film 2 is formed on the amorphous glass protective film 20 between the mounting position of the drive IC 9 and the heating resistor 6.
1 and a first ground electrode 15 is formed thereon.

Then, the protective film 20 on the signal wiring 13
The drive IC 9 is mounted thereon, and the individual electrode pads 11 and the output pads 10 of the drive IC are wire-bonded with gold wires 29. Further, the control signal pad 12 and the signal wiring pad 23 (FIG. 3) of the drive IC 9 further
The ground pad 19 of C9 and the second ground electrode 18 are respectively wire-bonded.

Then, the drive IC 9 rows and the wire-bonded portions are sealed with a sealing resin 16 (FIG. 5). At this time, the sealing portion may be entirely or partially covered in the width direction of the first ground electrode 15.

FIG. 5 shows a cross section taken along the line BB 'of FIG. The structure up to the formation of the protective film 20 is the same as the structure shown in FIG. This cross-sectional view shows a portion between the drive ICs 9, and the connection electrode 22 extending from the first ground electrode 15 reaches the second ground electrode 18 beyond the signal wiring 13, and the first ground electrode 15 And the second ground electrode 18 are connected.

In the above-described embodiment, as shown in FIG. 1, the mounting row of the driving ICs 9 and the row of the external connection terminal groups 14 are arranged in a single row, and both rows are arranged in a single row in the lateral direction of the insulating substrate 1. However, as another embodiment, as shown in FIG. 6, the mounting row of the drive IC 9 and the external connection terminal group 14 are different from each other.
May be arranged in two rows with the rows partially adjacent to each other in the lateral direction of the insulating substrate 1.

This is because when the external connection terminal group 14 is long in the horizontal direction, it cannot be accommodated in the thermal head substrate unless the row in which the drive ICs 9 are mounted and the row in the short direction of the insulating substrate 1 are arranged so as to be partially adjacent to each other. This is an effective arrangement. As a case where the external connection terminal group 14 must be lengthened, there are cases where the number of control signals increases and where the number of ground terminals and common terminals must be increased due to current capacity.

With such an arrangement, an empty space is created between the row of the external connection terminal groups 14 and the heating resistor 6, so that it can be effectively used for mounting a single component such as the thermistor 30. In the embodiment shown in FIG. 6, the external connection terminal group 14 is divided into left and right parts at the center.
a and 14b are provided and the connection is divided into two connectors. When the connector is divided into two, the connector cable thickness enters the central part, so that a long space is required in the lateral direction and the external The horizontal length of the connection terminal group is long.

In the case of this embodiment, the short side dimension of the insulating substrate is slightly larger than that of the embodiment of FIG. 2, but an empty space is generated below the row of mounting the drive ICs 9 instead. The second common electrode 7 is connected to the second short side 5 in this empty space.
External connection terminal group 1 from the portion along the end of the second long side 3
4 can be extended.

By doing so, the second common electrode 7 shown in FIG.
As described above, the conductor resistance of the common electrode provided from the common electrode terminal 24 of the external connection terminal group 14 to the right end of the insulating substrate 1 can be reduced. Thereby, the conductor resistance value difference between the left and right short portions of the second common electrode 7 is reduced, and the printing density difference can be reduced when printing is performed. As described above, although the short side dimension of the thermal head substrate is slightly increased, the print density difference can be reduced.

[0058]

According to the present invention, since the ground electrode is arranged on the insulating film on the individual electrode, the thermal head can be constructed without increasing the width of the insulating substrate even if the width of the ground electrode is increased. This leads to downsizing of the thermal head. In addition, since the external connection terminal group is centrally arranged at one place on one side of the insulating substrate, the resulting empty space can be effectively used for mounting other wiring and components.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a thermal head according to the present invention.

FIG. 2 is a detailed plan view of the thermal head of the present invention.

FIG. 3 is a detailed plan view of a drive IC mounting portion of the thermal head of the present invention.

FIG. 4 is a sectional view taken along line A-A 'of FIG.

FIG. 5 is a sectional view taken along line B-B 'of FIG.

FIG. 6 is another detailed plan view of the thermal head of the present invention.

[Explanation of symbols]

1. Insulating substrate 6. Heating resistor 7, 17 Common electrode 8. Individual electrode 9. Drive IC 14. External connection terminal group 15. First ground electrode 18. Second ground electrode 21 ..Insulating film 22..Connection electrode connecting first ground electrode 15 and second ground electrode

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Norio Yamaji 1 at 455 Kosai Minami-cho, Takamatsu City, Kagawa Prefecture

Claims (12)

[Claims] 1. A thermal head, comprising: a heating resistor disposed on a rectangular insulating substrate in a longitudinal direction of the insulating substrate; and a plurality of drive ICs disposed on the insulating substrate in a longitudinal direction thereof. The arrangement length of the plurality of drive ICs is arranged in an area shorter than the effective print width of the heating resistor, and the external connection terminal is provided in an empty space formed at one end on the long side of the insulating substrate. The thermal head is characterized by intensively disposing. 2. The size from the short side of the insulating substrate near the right and left end dots in the effective print width area of the heating resistor is set such that the size on one dot side is larger than the size on the other dot side. 2. The thermal head according to claim 1, wherein the external connection terminals are arranged in a concentrated manner at the long side end of the insulating substrate on the side where the size is increased. 3. A heating resistor disposed on a rectangular insulating substrate in a longitudinal direction of the insulating substrate; a driving IC disposed on the insulating substrate in a longitudinal direction thereof; A thermal head comprising: an insulating film provided on an individual electrode connected to a driving IC; and a ground electrode provided on the insulating film along a longitudinal direction of the insulating substrate. 4. The thermal head according to claim 3, wherein said ground electrode is formed of a metal material containing silver as a main component. 5. The thermal head according to claim 3, wherein the insulating film has a two-layer structure, one of the insulating films is a crystallized glass layer, and the other is an amorphous glass layer. 6. A thermal head in which a heating resistor and a plurality of driving ICs are provided on a rectangular insulating substrate in a longitudinal direction of the insulating substrate, an insulating member provided on individual electrodes derived from the heating resistor. A film, a first ground electrode provided on the insulating film along a longitudinal direction of the insulating substrate, and a longitudinal direction of the insulating substrate on a side opposite to the first ground electrode with respect to the plurality of driving ICs. And a second ground electrode connected to each ground pad of the plurality of drive ICs and a drive IC adjacent to the plurality of drive ICs.
A thermal head comprising: a connecting means for electrically connecting to a ground electrode. 7. The thermal head according to claim 6, wherein the first ground electrode is formed of a metal material containing silver as a main component. 8. The thermal head according to claim 6, wherein the insulating film has a two-layer structure, one of the insulating films is a crystallized glass layer, and the other is an amorphous glass layer. 9. A thermal head in which a heating resistor and a plurality of driving ICs are provided on a rectangular insulating substrate in a longitudinal direction of the insulating substrate, a plurality of signal wirings respectively connected to external connection terminals are connected to the driving IC. A thermal head, which is arranged below a row and between a drive IC and a connection pad of an individual electrode derived from the heating resistor. 10. The size from the short side of the insulating substrate near the right and left end dots in the effective print width area of the heating resistor is set such that the size on one dot side is larger than the size on the other dot side. 10. The thermal head according to claim 9, wherein the external connection terminals are concentratedly arranged at the long side end of the insulating substrate on the side where the size is increased. 11. A thermal head in which a heating resistor and a plurality of driving ICs are provided on a rectangular insulating substrate in a longitudinal direction of the insulating substrate, an insulating member provided on an individual electrode derived from the heating resistor. A film, a first ground electrode provided on the insulating film along a longitudinal direction of the insulating substrate, and a longitudinal direction of the insulating substrate on a side opposite to the first ground electrode with respect to the plurality of driving ICs. And a second ground electrode connected to each ground pad of the plurality of drive ICs and a drive IC adjacent to the plurality of drive ICs.
Connection means for electrically connecting the ground electrode to the ground electrode, wherein the dimension from the short side of the insulating substrate near the right and left end dots in the effective print width area of the heating resistor is set, and the size on one dot side is set to the other. External connection terminals are concentrated on the longer side end of the insulating substrate on the side where the size is larger than the size on the dot side, and a plurality of signal wirings respectively connected to the external connection terminals are arranged under the drive IC row. And a thermal head arranged between the drive IC and connection pads of the individual electrodes. 12. A driving IC adjacent to the plurality of driving ICs.
12. The thermal head according to claim 11, wherein the plurality of signal wirings and the respective driving ICs are connected between C.