JPH07314755A - Thermal print head - Google Patents

Abstract

PURPOSE:To contrive to miniaturize a thermal print head having a type, in which printing density is enhanced by providing two rows of heating dot train in parallel to each other. CONSTITUTION:IN a thermal print head, in which a first heating dot train Ra and a second heating dot train Rb are provided on a substrate 1 in parallel to each other at a predetermined interval under the condition that the respective heating dots of the two rows of the heating dot train are staggered each other by 1/2 pitch to their arranging direction, common lines 5a and 5b connecting with the respective common electrodes 3a and 3b in the two rows of the heating dot trains Ra and Rb are arranged outside the two rows of the heating dot trains Ra and Rb. At the same time, the common lines 5a and 5b are arranged so as to get under driving ICs 6a and 6b connecting with individual electrodes 4a and 4b for drivingly controlling two rows of the heating dot train Ra and Rb mounted on the substrate 1 in unit heating dot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal print head incorporated in a printer device, a facsimile device or the like.

[0002]

2. Description of the Related Art A thermal print head of this type is disclosed in, for example, Japanese Patent Laid-Open No. 57-107864. As shown in FIG. 12, the thermal print head disclosed in this publication has heating resistors 2 arranged in parallel in two columns, and a comb-teeth-shaped common electrode 3e and an individual electrode 4e are provided below these heating resistors 2. By providing and, two heating dot rows Re and Rf are formed. The heat generating dots of the two heat generating dot rows Re and Rf are displaced from each other by ½ pitch in the row direction.

In the thermal print head having the above structure,
When printing out the print data on the recording paper, first, the odd bit data of the print data for one line is printed in the first heating dot row Re. Next, the recording paper is fed in the sub-scanning direction by the same dimension as the dimension La between the two heating dot rows Re and Rf, and then even-bit data is printed in the second heating dot row Rf. In this way, by printing the print data for one line by the two rows of heating dots Re and Rf in which the pitches of the heating dots are displaced from each other, the print dot density can be doubled and the image And characters can be printed precisely.

However, in the above-mentioned one, two lines of common lines 5e for supplying current to each common electrode 3e,
5f is arranged inside the two heating dot rows Re and Rf. Therefore, in such a configuration,
Since it is necessary to secure a space for forming the two rows of common lines 5e, 5f between the two rows of the heating dot rows Re, Rf, these two rows of the heating dot rows Re,
The mutual dimension La of Rf was large.

Also, these common lines 5e, 5f
Generally, only the connection terminal portions (not shown) for voltage application are provided at both ends thereof. Therefore,
Due to the voltage drop occurring in the central portion of the common lines 5e and 5f in the longitudinal direction,
It is necessary to supply a considerable amount of current to e and 5f. In addition, since the overall power consumption increases as the number of dots in the two heating dot rows Re and Rf increases, the current value supplied to the common electrode 3e may also have to be increased for this reason. Therefore, in the thermal print head having the above-described structure, as shown in FIG. 13, the width S of each common line 5e, 5f needs to be considerably wide. Therefore, it is difficult to reduce the width S of the common lines 5e and 5f to reduce the mutual dimension La of the two heating dot rows Re and Rf, and the dimension La is considerably large.

As a result, in the above-mentioned thermal print head, a total of 2 dots corresponding to each of the heating dot rows Re and Rf are obtained.
Since individual platen rollers are required, there have been problems that the structure of the entire printer device is complicated and the size is increased.

Therefore, the present applicant has previously proposed the thermal print head disclosed in Japanese Patent Publication No. 3-31588 as a means for solving the above-mentioned problems. As shown in FIG. 14, the thermal print head disclosed in this publication has predetermined circuit elements 65 and 65 on both outer sides of the heating dot rows Re and Rf provided in parallel with each other, and further has a common circuit on the outer side thereof. This is a configuration in which the lines 5e and 5f are arranged in two rows each. By arranging the common lines 5e and 5f outside the two heating dot rows Re and Rf in this way, the mutual dimension La between the two heating dot rows Re and Rf can be reduced. When configuring the printer device, one platen roller can be used.

[0008]

However, in the conventional device shown in FIG. 14, the drive IC 6 for incorporating the shift register or the like to control the on / off of the individual electrode 4e is provided.
e and 6f are arranged outside the common lines 5e and 5f. For this reason, conventionally, the dimension Lb between the drive ICs 6e and 6f becomes considerably large, and the entire thermal print head becomes large in size, which causes a problem in downsizing the printer device.

The present invention has been devised under the above circumstances, and when two rows of heating dots are provided in parallel to increase the printing density of the thermal print head, two rows of heating dots are used. It is an object of the present invention to solve the problem that the distance between rows and the distance between drive ICs become large and to appropriately reduce the size of the thermal print head.

[0010]

In order to solve the above problems, the present invention takes the following technical means.

That is, in the invention described in claim 1 of the present application, the first heat generation dot row and the second heat generation dot row are provided in parallel at a predetermined interval on the substrate. The dot row is formed by providing a comb-teeth-shaped common electrode and an individual electrode extending between the common electrodes so as to traverse a strip-shaped heat-generating resistor having a predetermined width. Each of the heating dots in a row is a thermal print head which is displaced from each other by ½ of the heating dot pitch in the arrangement direction, and a common line connected to each common electrode in the two heating dot rows. Is arranged on the outside between the two rows of heating dots, and the common line is mounted on the substrate to drive and control each of the two rows of heating dots in units of heating dots. Ku is characterized in that it is arranged so as to dive under the drive IC connected to said individual electrodes.

According to a second aspect of the present invention, in the thermal print head according to the first aspect, each common electrode in the two heating dot rows extends outwardly between the two heating dot rows. It is characterized in that they are respectively connected to two common lines arranged on both outsides between these two rows of heating dot rows.

According to a third aspect of the present invention, in the thermal print head according to the first aspect, the thermal print head is positioned inside the two rows of heating dots and is displaced from each other by 1/2 pitch of the heating dot pitch. One end of each common electrode is connected to each other, and the other end of the common electrode in any one of the two heating dot rows is the two heating dot rows. It is characterized in that it is extended in the outer direction between and is connected to one common line arranged outside between these two rows of heating dots.

According to a fourth aspect of the present invention, in the thermal print head according to the first aspect, one end of each common electrode located inside the two rows of heating dots is formed in a strip shape. Connected in series via the electrode connecting portion, and the other end portions of some of the common electrodes in each of the common electrodes in at least one of the two heating dot rows are It is characterized in that it is extended in the outer direction between the two rows of heating dots and is connected to a common line arranged outside between the two rows of heating dots.

According to a fifth aspect of the present invention, in the thermal print head according to any one of the first to fourth aspects, the common line is located at an intermediate portion in the longitudinal direction other than both ends of the common line. It is characterized in that at least one or more connection terminal portions for applying a voltage are additionally provided.

According to a sixth aspect of the present invention, in the thermal print head according to any one of the first to fifth aspects, the width of the portion of each common electrode overlapping the heating resistor is the first heating dot. It is characterized in that the heating dots in the row and the heating dots in the second heating dot row are expanded so as to reduce the overlapping dimension.

The invention described in claim 7 of the present application is the above 2
Each heating resistor of each row of heating dots is provided on the surface of the glaze projecting on the substrate and having an arcuate cross section so as to be line-symmetric with respect to the center line along the longitudinal direction of the glaze. It is characterized by being.

[0018]

In the thermal print head according to the present invention, the common line connected to each common electrode is arranged outside between the two rows of heating dots and is provided so as to dive under the drive IC. Therefore, unlike the case where the common line is provided between the two rows of heating dots, it goes without saying that these two rows of heating dots can be provided close to each other, and the above-mentioned drive ICs are provided in two rows. It can also be provided quite close to the heat generating dot row. That is, since it is not necessary to secure the common line arrangement area separately from the area for mounting the drive IC,
Both the common line and the driving IC, which are arranged outside the two rows of heating dots, can be provided very close to the two rows of heating dots.

As a result, it is necessary to reduce the size of the substrate for providing each of the two rows of heating dots, the common line, and the drive IC, especially the dimension in the width direction to reduce the width of the entire thermal print head. As a result, it is possible to obtain a special effect that the printer device, the facsimile device, and the like having the thermal print head incorporated therein can be downsized.

In the present invention, since the mutual dimension of the two heating dot rows can be reduced as described above, it is not necessary to use two platen rollers for printing, and a relatively small diameter is used. Of course, it is possible to deal with this by using individual platen rollers. Further, current is supplied to each common electrode from the common line arranged outside between the two rows of heating dots, and the drive ICs arranged above the common line and connected to the individual electrodes are driven. If so, each heating dot of the two heating dot rows can be made to generate heat in dot units, and fine printing can be appropriately performed with a printing density twice as high as the dot density of each heating dot row. As described above, in the present invention, there is no inconvenience caused by changing the position of the common line to a position different from the conventional position.

According to the invention described in claim 2, when the heat generation driving of each heat generation dot of the two heat generation dot lines is performed, each common electrode of the two heat generation dot lines has two common lines. These 2 are connected to each individually.
By individually applying a voltage to each of the common lines of the book, the first heating dot row and the second heating dot row can be individually heated. Therefore, there is an advantage that a control method of controlling the heat generation driving of each heat generation dot of the two heat generation dot rows by turning on / off the voltage application to the two common lines is also possible.

According to the invention described in claim 3, 1
If a voltage is applied to the common line of the book, current can be simultaneously supplied to both common electrodes of the two rows of heating dots whose one ends are mutually connected. In this case, since the number of common lines is one, which is the minimum number, and it is not necessary to extend all the common electrodes to the common line side, the pattern formation of these common electrodes and common lines becomes easy. Further, the number of steps for connecting the power supply wiring to the common line when manufacturing the thermal print head can be reduced. As a result, the manufacturing process can be simplified,
There is an advantage that the manufacturing work can be facilitated and the manufacturing cost can be reduced.

Further, according to the invention of claim 4,
Since one end of each common electrode is connected in series via the electrode connecting portion formed in a strip shape and some of these common electrodes are extended and connected to the common line, all of the common electrodes are extended. Compared with the case, the pattern formation of the common electrode is also easy. Therefore, there is an advantage that the yield at the time of pattern formation can be improved.

Between the two rows of heating dots,
Although the strip-shaped electrode connecting portion is formed, the plurality of common electrodes connected to the electrode connecting portion are connected to the common line, so that current is supplied to the electrode connecting portion from a plurality of locations. Therefore, the voltage drop at the electrode connecting portion is small, and it is not necessary to supply an excessive current to the electrode connecting portion in consideration of this voltage drop.
Therefore, it is not necessary to increase the width of the electrode connecting portion, and there is no problem that the mutual dimension of the two heating dot rows becomes unduly large.

According to the fifth aspect of the present invention, since the connecting terminal portion for applying a voltage is also provided at the central portion in the longitudinal direction other than both ends of the common line, the connecting terminal is provided. By applying a voltage to the portion, it is possible to eliminate the voltage drop in the central portion of the common line in the longitudinal direction. Therefore, each heating dot of the heating dot row can be uniformly heated to an appropriate temperature in each place,
Good quality and proper printing can be performed.

According to the sixth aspect of the present invention, each of the common electrodes has an expanded portion overlapping with the heating resistor, so that the heating dots of the first heating dot row and the second heating dot row are formed. The overlapping size with the heating dots becomes smaller. Therefore, it is possible to perform printing with doubled printing density with higher quality.

According to the seventh aspect of the invention, since the two rows of heating dots are arranged symmetrically on the surface of the glaze projecting on the substrate, the heating resistors of these two rows of heating dots are provided. The contact of the thermal recording paper can be improved. Therefore, there is an effect that the quality of printing can be further improved.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below.
A specific description will be given with reference to the drawings.

FIG. 1 is a partially enlarged plan view showing an embodiment of a thermal print head according to the present invention. This thermal print head is provided with a first heating dot row Ra and a second heating dot row Rb in parallel with each other on a substrate 1 made of alumina ceramics, for example.
Common lines 5a and 5b are formed outside the two heating dot rows Ra and Rb, and drive ICs 6a and 6b are formed above the common lines 5a and 5b.
Has been implemented.

The method of forming the two heating dot rows Ra and Rb is the same as the method of forming the heating dot rows in the conventional thick film type thermal print head. That is, each of the heating dot rows Ra and Rb is a comb-teeth-shaped common electrode extending in the width direction of each heating resistor 2 below the heating resistors 2 and 2 formed in a band shape of a predetermined width by a thick film printing method. 3a, 3b
And individual electrodes 4a and 4b extending between the comb-teeth-shaped common electrodes 3a and 3b.

FIG. 2 is a sectional view taken along the line II of FIG. A glass glaze layer 7a is formed on the surface of the substrate 1, and the common electrodes 3a and 3b and the individual electrode 4 are formed on the glass glaze layer 7a.
a, 4b, etc. are formed. Further, heat generating resistors 2 and 2 are formed thereon, and the entire surface of these is covered with a protective layer 7b made of glass or the like. Although the protective layer 7b is directly provided on the common line 5a in the figure, a common reinforcing layer (not shown) is provided on the common line 5a as a means for increasing the current capacity of the common line 5a. It may be formed by overprinting.

In FIG. 1, the above two rows of heating dot rows R
Minimum unit of heating dots in a and Rb (1 dot)
Is the range indicated by the cross-hatched portions A and B. That is, one individual electrode 4a or 4b is connected to the driving IC 6a.
Or when it is turned on by 6b, in the range between the individual electrode 4a and the two common electrodes 3a and 3a located on both sides thereof, or between the individual electrode 4b and the two common electrodes 3b and 3b located on both sides thereof. The heating resistor 2 is energized to heat it. The first heating dot row Ra and the second heating dot row Rb are displaced from each other by ½ pitch of the heating dot pitch P along the row direction.

In each of the common electrodes 3a and 3b, a wide portion 30 is formed in a portion overlapping the lower layer of the heating resistor 2, and the width S2 of the wide portion 30 is larger than the width S1 of other portions. It is in an expanded state. In the present invention, for example, as shown in FIG. 3, the widths of the respective portions of the common electrodes 3a and 3b may be formed to have the same dimension S1, but in the configuration shown in FIG. 1, the wide portions 30 are formed in the respective common electrodes 3a and 3b. By being partially formed, the width of the heating dots A, B is smaller than the width of the heating dots Aa, Ba shown in FIG.

One end of each of the common electrodes 3a and 3b extends outwardly between the two heating dot rows Ra and Rb, and is arranged outside the two heating dot rows Ra and Rb. Connected to the common lines 5a and 5b.

The common lines 5a and 5b are arranged on both outer sides of the two heating dot rows Ra and Rb.
It is formed so as to be located below the drive ICs 6a and 6b. These common lines 5a and 5b are formed along the longitudinal direction (left and right direction in FIG. 1) of the substrate 1 so as to be parallel to the two heating dot rows Ra and Rb. Side edge 1a of substrate 1 or side edge 1
The extending portion 50 extending in the b direction is formed, and the connecting terminal portion 51 is formed.

This connecting terminal portion 51 is provided for each common electrode 5
The wiring for power supply is provided for supplying current to a and 5b. Such a connection terminal portion 51,
The common lines 5a and 5b are formed at a total of two places on both left and right ends, and as shown in FIG. 4, for example, a plurality of places are also provided at a predetermined pitch in the central portion of the common lines 5a (and 5b) in the longitudinal direction. Has been. In addition, each of the connection terminal portions 51 has, for example, the drive ICs 6a and 6a (and 6b and 6b) so that the power supply wiring can be easily connected.
Are located between each other.

The drive ICs 6a and 6b perform on / off control of the individual electrodes 4a and 4b so as to drive and control each of the two heat generation dot rows Ra and Rb. Specifically, each of these drive ICs 6
The a and 6b are provided with a plurality of output pads 60, and these output pads 60 are connected to the wire bonding pads 40 formed at the ends of the individual electrodes 4a and 4b by wire bonding.

A shift register 61 is built in each of the drive ICs 6a and 6b.
The print data input from the data-in pad Din is serially input to 1 according to the clock pulse signal from the clock pulse pad CPic. Then, when the strobe signal is input to the strobe pad STR, the transistor Tr at the location corresponding to the dot to be printed is turned on based on the print data input to and held in the shift register 61.

As a result, the individual electrodes 4a, 4 connected to the output pad 60 in which the transistor Tr is turned on.
A current flows between b and the common electrodes 3a and 3a located on both sides thereof, or between the common electrodes 3b and 3b, and the heating resistor 2 generates heat in the above-described dot unit.

In the thermal print head having the above structure, as is apparent from FIG.
Since the a and 5b are provided under the lower surfaces of the drive ICs 6a and 6b, the formation regions of the common lines 5a and 5b are
It is not necessary to secure it separately from the mounting area of the drive ICs 6a and 6b. That is, since the drive ICs 6a and 6b are arranged on the common lines 5a and 5b, the drive ICs 6a and 6b are not provided.
By making a and 6b close to the two heating dot rows Ra and Rb, the mutual dimension of these drive ICs 6a and 6b can be reduced. Therefore, the width of the entire substrate 1 can be reduced, and the thermal print head can be downsized.

Since the common lines 5a and 5b are not provided between the two heating dot rows Ra and Rb, these two heating dot rows Ra and Rb are brought close to each other and these The mutual dimension L can be minimized. Thus, the two rows of heating dot rows Ra and Rb
As shown in FIG. 5, the outer diameter is, for example, 3
Even when one platen roller 8 having a relatively small diameter of 0 mm and a nip width (crushed width) of about 3 to 4 mm is used, both plate rows Ra and Rb of two rows are generated by this platen roller 8. It is possible to press simultaneously and it is not necessary to use two platen rollers for printing. The mutual distance L (center-to-center distance L) between the two heating dot rows Ra and Rb is an integral multiple of the paper feed pitch in the sub-scanning direction indicated by the arrow a in FIG. It is possible to have two pitches.

Next, description will be given of a case where printing is performed on a recording sheet using the thermal print head having the above-mentioned configuration. In this printing, first, one of the two drive ICs 6a and 6b is driven. As a result, of the two heating dot rows Ra and Rb, the first heating dot row R
It is possible to generate heat in the heat generating dot a. In this first heating dot row Ra, odd-numbered dot print data N1, N3, N5, ... Of the predetermined number of print data for one line are printed, for example, as shown in FIG.

Next, after the printing of the above data is completed, the recording paper is fed in the sub-scanning direction, and the line on which the odd-numbered dot print data N1, N3, N5 ... Face the heating dot row Rb. Then, in this state, the other driving IC 6b is driven to print the even-numbered dot print data N2, N4, N6 ... As shown in FIG. 6B by the second heating dot row Rb.

Since the respective heating dots of the first heating dot row Ra and the second heating dot row Rb are misaligned by 1/2 pitch, a series of printing dots printed as described above is printed. The density is substantially double the dot pitch of each heating dot row Ra, Rb. That is, the dot pitch P of each heating dot row Ra, Rb is set to 12 for example.
When it is set to 8 μm and 200 dpi (dot / inch), it is substantially doubled to 400 dpi.

Further, in the above-mentioned thermal print head, the width of the heating dots A and B of the heating dot rows Ra and Rb is set narrow by providing the wide portions 30 on the common electrodes 3a and 3b. The width Sa of each print dot shown in FIG. 6 is also small. For this reason, the overlapping width Sb of each print dot can be reduced, and precise printing can be performed.

Further, during the above-mentioned printing process, a voltage is applied to each of the common lines 5a and 5b.
A voltage is applied to each of the common lines 5a and 5b not only from both ends thereof but also from each of a plurality of connection terminal portions 51 provided at the central portion in the longitudinal direction. Therefore, a large voltage drop does not occur in the central portion of the common lines 5a and 5b in the longitudinal direction, and the heat generation dots of the two heat generation dot rows Ra and Rb are uniformly and appropriately heated. Can be made. As a result, the print dots do not vary due to the temperature difference of the heating dots, and the print quality can be further improved.

FIG. 7 shows a second embodiment of the thermal print head according to the present invention (note that FIG. 1 and FIG. 2).
The same parts as those in the first embodiment shown by are denoted by the same reference numerals. The same applies to other figures after FIG. 8). The thermal print head shown in FIG. 7 differs from that of the first embodiment shown in FIG. 1 in that the positions of the two heating dot rows Ra and Rb are displaced by ½ of each heating dot pitch. One end of the common electrodes 3 a and 3 b is connected to each other via the connecting portion 31. Further, of these common electrodes 3a and 3b, the other end side of one common electrode 3a is extended outward between the two heating dot rows Ra and Rb, and is formed so as to dive under the drive IC 6a. 1
It is connected to the common line 5a of the book.

In the above structure, even if the voltage is applied to one common line 5a, the common electrodes 3a and 3b are not required.
Current can be supplied to both of them simultaneously. Then, by controlling the on / off of the individual electrodes 4a and 4b by the drive ICs 6a and 6b, the respective heating dots of the two heating dot rows Ra and Rb are doted as in the case of the above-described first embodiment. Appropriate heat can be generated in units and high density printing can be performed.

Further, in the thermal print head having the above structure, the connecting portion 31 is provided between the two heating dot rows Ra and Rb.
However, the mutual dimension of these two heating dot rows Ra and Rb can also be reduced. Further, since the common line 5a is formed under the lower surface of the drive IC 6a, the size of the substrate 1 in the width direction can be reduced, and the thermal print head can be downsized.

Further, in the thermal print head having the above-mentioned structure, since only one common line 5a is formed on the substrate 1, the pattern formation is easier than in the case where two common lines are formed. Becomes Also,
The power supply wiring connection for supplying the current to the common electrodes 3a and 3b only needs to be made to one common line 5a, so that the wiring processing can be facilitated.

FIG. 8 is an overall schematic plan view showing a third embodiment of the thermal print head according to the present invention, and FIG. 9 is FIG.
3 is an enlarged plan view of a C portion of FIG. As shown in FIG. 9, the thermal print head includes common electrodes 3c and 3d formed on the lower surfaces of the heating resistors 2 and 2 arranged in parallel in two columns.
One end of each of the common electrodes 3c and 3d is connected in series via the electrode connecting portion 32 formed in the shape of a strip, and the common electrodes 3c and 3d are formed in a comb tooth-like shape protruding to both sides of the electrode connecting portion 32. The plurality of comb-shaped common electrodes 3c, 3
d is, for example, one of the four common electrodes 3
c ′ and 3d ′ have two rows of heating dot rows Ra and R on the other end side
It is stretched in the outer direction of b.

Part of the stretched common electrode 3
The individual electrodes 4c and 4d extending between the common electrodes 3c and 3d and the common electrodes 3c and 3d are extended to the positions of the pattern forming portions 9a and 9b shown in FIG. It has been stretched. The pattern forming portions 9a and 9b
Are symmetrical with each other, and one pattern forming portion 9a
Are formed in a pattern as shown in FIG. 10, for example. The pattern forming portion 9a forms a plurality of wire pad portions 43a for connecting the extending portion 43 of the individual electrode 4c to the drive IC 6a via a wire W such as a gold wire in series, and these wire pad portions 43a are formed. The bent portion 33 of the common electrode 3c 'is arranged at an appropriate position. The extending portion 33 of the common electrode 3c 'is driven by the drive I
It is connected to a common line 5a formed so as to dive under C6a. In FIG. 8, the other pattern forming portion 9b has the same structure as the one pattern forming portion 9a described above. Then, the common electrode 3 is formed on the common line 5b formed below the drive IC 6b.
The extension part 33 of d'is connected.

Also in the thermal print head according to the third embodiment described above, the common lines 5a and 5b are also the same.
Are arranged so as to go under the drive ICs 6a and 6b, so that the overall size in the width direction can be reduced. Further, as the pattern formation of the common electrodes 3c and 3d, only some of the common electrodes 3c 'and 3d' are extended to the positions of the common lines 5a and 5b. Therefore, as compared with the case where all the common electrodes 3c and 3d are extended to the positions of the common lines 5a and 5b, the pattern shape of the common electrodes 3c and 3d as a whole can be simplified and the yield at the time of pattern formation can be improved. It will be possible.

Further, in the above-mentioned thermal print head, the plurality of common electrodes 3c 'and 3d' have the common line 5
Since they are connected to a and 5b, each common electrode 3c, 3
In d, voltage is applied from a plurality of places. Therefore, a voltage drop is unlikely to occur in each of the common electrodes 3c and 3d, and it is possible to evenly generate heat in each heating dot of the two heating dot rows Ra and Rb.

Although the strip-shaped electrode connecting portion 32 is formed between the two heating dot rows Ra and Rb, only one electrode connecting portion 32 is required, and as described above, each electrode connecting portion 32 is formed. Since the common electrodes 3c and 3d have little voltage drop, it is not necessary to make the width of the electrode connecting portion 32 so large. Therefore, even if the electrode connecting portion 32 is formed between the two heating dot rows Ra and Rb, the dimension between the two heating dot rows Ra and Rb does not become so large. As shown in FIG. 5, it is possible to perform proper printing by using the single platen roller 8 having a relatively small diameter.

In the third embodiment shown in FIG. 8, both the common electrodes 3c 'and 3d' are connected to the common lines 5a and 5b.
Although the case of connecting to the above has been described, the present invention does not necessarily have to be configured in this way. For example, only one of the common lines 5a and 5b may be formed and only one of the common electrodes 3c 'and 3d' may be connected to the common line 5a. Even with such a configuration, since the common electrodes 3c and 3d are connected to each other through the electrode connecting portion 32, both common electrodes 3c and 3d are connected to each other.
This is because it is possible to appropriately apply a voltage to c and 3d. With such a configuration, there is an advantage that the pattern shapes of the common electrodes 3c and 3d can be further simplified.

FIG. 11 is a cross-sectional view of essential parts showing another embodiment of the heating dot rows Ra and Rb of the thermal print head according to the present invention. With this thermal print head,
A glass glaze layer 10 protruding in an arcuate cross section is formed on the surface of the substrate 1, two heating resistor rows 2 and 2 are formed on the surface of the glass glaze layer 10, and heating dot rows Ra and R are formed.
b are provided in parallel. The two heating dot rows Ra and Rb are arranged in line symmetry with respect to the center line CL along the longitudinal direction of the glass glaze layer 10. In addition,
In the figure, illustration of the common electrodes and individual electrodes is omitted.

According to the above configuration, the heating resistors 2, 2
Since the glass glaze layer 10 formed with is partially projected from the surface of the substrate 1, the contact of the heating resistors 2 and 2 with the platen roller 8 can be made good. Therefore, as shown in FIG. 5, as compared with the case where the heating resistors 2 and 2 are provided flat, the contact with the recording paper and the heating can be ensured, and there is an advantage that the quality of printing can be improved. . Such a configuration is applicable to any of the thermal print heads of the above-described first to third embodiments.

In each of the above embodiments, one substrate 1
The case where two or more common lines 5a and 5b are formed and the common electrodes are connected to them has been described.
The present invention is not necessarily limited to this. For example, as shown in FIG. 14 described as a conventional example, two common lines are formed corresponding to one heating dot row, and a total of four common lines are formed.
You may make it form the common line of a book.

In addition, in the present invention, the specific number and pitch of the common electrodes and the individual electrodes can be variously changed in design in accordance with the usage conditions and the like. Needless to say, the specific circuit configuration of the drive IC is not limited to the configuration of the above embodiment.

[Brief description of drawings]

FIG. 1 is an enlarged plan view of an essential part showing an embodiment of a thermal print head according to the present invention.

FIG. 2 is a cross-sectional view taken along the line I-I of FIG.

FIG. 3 is an enlarged plan view of an essential part showing another example of the shape of the common electrode of the thermal print head according to the present invention.

FIG. 4 is a main part schematic perspective view showing an example of a plurality of connection terminal parts provided on a common line.

FIG. 5 is a cross-sectional view of essential parts showing a state in which a platen roller is in contact with a heating dot row.

6 (a) and 6 (b) are explanatory views showing a process when printing is performed by the thermal print head shown in FIG.

FIG. 7 is a second thermal print head according to the present invention.
FIG. 3 is an enlarged plan view of an essential part showing the embodiment of FIG.

FIG. 8 is a third thermal print head according to the present invention.
FIG.

9 is an enlarged plan view of a C portion of FIG.

10 is an enlarged plan view of an essential part of the thermal print head shown in FIG.

FIG. 11 is a cross-sectional view of an essential part showing another configuration example of a heating dot row of the thermal print head according to the present invention.

FIG. 12 is a schematic explanatory view showing an example of a conventional thermal print head.

13 is a plan view of a principal part showing pattern formation of a heating dot row in the conventional thermal print head shown in FIG.

FIG. 14 is a plan view showing another example of a conventional thermal print head.

[Explanation of symbols]

 1 substrate 2 heating resistor 3a-3d common electrode 4a-4d individual electrode 5a, 5b common line 6a, 6b drive IC 8 platen roller 30 wide part 32 electrode connection part 51 connection terminal part Ra first heating dot row Rb second Fever dot row

Claims (7)

[Claims] 1. A first heat generation dot row and a second heat generation dot row are provided in parallel on a substrate at a predetermined interval, and each heat generation dot row has a band-shaped heat generation having a predetermined width. It is formed by providing a comb-teeth-shaped common electrode and an individual electrode extending between the common electrodes so as to traverse the resistor, and the respective heat-generating dots of the two heat-generating dot rows are mutually arranged in the heat-generating dot pitch. In the thermal print head, which is displaced by 1/2 pitch in the arrangement direction, the common line connected to each common electrode in the two heating dot rows is between the two heating dot rows. A drive IC which is arranged on the outside and is connected to the individual electrode so that the common line is mounted on the substrate and drives and controls each of the two rows of heat generation dots in units of heat generation dots. Characterized in that it is arranged so as to dive under the thermal print head. 2. The common electrodes in the two rows of heating dots are extended in the outer direction between the two rows of heating dots, and are arranged on both outer sides between the two rows of heating dots. The thermal print head according to claim 1, wherein each of the thermal print heads is connected to a common line of a book. 3. One end of each common electrode located inside the two rows of heating dots and displaced from each other by 1/2 pitch of the heating dot pitch is connected to each other, and The other end of the common electrode in any one of the two heating dot rows is extended in the outer direction between the two heating dot rows so as to extend outside the two heating dot rows. The thermal print head according to claim 1, wherein the thermal print head is connected to one common line arranged in 4. One end portion of each common electrode located inside the two rows of heating dots is connected in series via an electrode connecting portion formed in a strip shape, and the two rows of heat generation are performed. The other ends of some of the common electrodes in each of the common electrodes in at least one of the heat generating dot rows of the dot rows are extended in the outer direction between the above two heat generating dot rows, and The thermal print head according to claim 1, wherein the thermal print head is connected to a common line arranged outside the heating dot rows. 5. The common line is further provided with at least one or more connecting terminal portions for applying a voltage to the common line at an intermediate portion in the longitudinal direction other than both ends thereof. The thermal print head according to any one of claims 1 to 4, which is characterized in that: 6. Each of the common electrodes has a width of a portion overlapping with a heating resistor that is equal to that of a heating dot of a first heating dot row and a second heating dot row.
The thermal print head according to claim 1, wherein the thermal print head is expanded so as to reduce the overlapping size of the heating dot row with the heating dot. 7. The heat generating resistors of the two heat generating dot rows are line-symmetric with respect to a center line along the longitudinal direction of the glaze on the surface of the glaze provided on the substrate and protruding in an arc shape in section. The thermal print head according to any one of claims 1 to 6, wherein the thermal print head is provided as follows.