JPH0781114A - Thermal head - Google Patents

Abstract

PURPOSE:To prevent a common electrode part from heating by a method wherein at least two wiring patterns for a strobe signal are provided to a signal wiring pattern part, and each wiring pattern for strobe signal is connected to a strobe signal terminal of at least every second driving IC. CONSTITUTION:In a thermal head having leader patterns of a common electrode 31-1, 31-2 from a heating element 2 at both ends of driving IC 5-1, 5-2,..., two wiring patterns for a strobe signal 61S1, 61S2 are provided to a signal wiring pattern part 61. Then, the wiring pattern 61S1 is connected to every second driving IC 5-1, 5-3,..., and besides the wiring pattern 61S2 is connected to every second driving IC 5-2 adjacent to the driving IC 5-1, 5-3. Consequently a current flowing to a common electrode pattern part is decreased to about one half, and electric power consumed in the common electrode part is extremely reduced. Heating at a cross part of the common electrode part can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head having a lead pattern forming a common electrode portion between drive ICs.

[0002]

2. Description of the Related Art In order to provide a real edge type by reducing the width of a common electrode pattern formed at an edge and to provide a small size and easy lead pattern etching process, the present inventors have , A thermal head having a common electrode pattern portion with a lead-out pattern extending in the direction of the other end portion on the substrate from the electrode pattern portion through the adjacent drive ICs has been created and already applied (actual application) Flat 2-
15970).

Regarding the thermal head according to this application,
This will be specifically described. As shown in FIG. 2, this thermal head is provided with a heating resistor film on the upper surface of the insulating substrate 1 to form a heating resistor 2, and the heating resistor 2 has an edge near the edge of the insulating substrate 1. It is formed in parallel. A common lead pattern (common electrode pattern) 3 is formed between the heating resistor 2 and the one end edge portion of the insulating substrate 1. The common lead pattern 3 is a pattern 30 parallel to the heating resistor 2.
And a comb-teeth-shaped piece 33 extending so as to cross the heating resistor 2 and the pattern portion 30 between adjacent drive ICs 5 arranged in parallel facing the heating resistor 2, respectively. It is integrally configured with a lead-out pattern 31 that is drawn out toward the other end of the insulating substrate 1. On the other hand, the insulating substrate 1
An individual lead pattern (individual electrode pattern) 4 is formed so as to cross the heating resistor 2 on the upper surface of the. The comb-shaped piece 33 of the individual lead pattern 4 and the common lead pattern 3
Are alternately arranged in a permutation on the heating resistor 2 in a facing manner.

In this thermal head, the drive IC 5
By pulling out the common electrode pattern 3 for each drive IC
A current of 5 pieces flows into the common electrode pattern 3. In practice, only the current of one drive IC 5 is used for the lead used as the common, so that the common electrode pattern 3 having a large width is not necessary. Therefore, the common electrode pattern 3 arranged between the heat generating resistor 2 and the edge of the insulating substrate 1 can be set to be extremely narrow, and the heat generating resistor 2 can be arranged so close to the edge of the insulating substrate 1. Possible,
Can be miniaturized.

[0005]

In the conventional thermal head described above, an individual electrode corresponding to, for example, a 64-bit heating resistor connected to one drive IC is formed in the extraction pattern portion of one common electrode pattern portion. The current will flow. Therefore, when performing printing with a high image density, that is, when performing printing close to all 64 bits, a relatively large current is applied to the lead-out lead pattern line of the common electrode and the cross portion with the heating resistor connected thereto. The flow and the lead portion of the cross portion connected to the drawing pattern generate heat. Now, for example, when a heating resistance value is 3000Ω, a lead wire is 25 μm, a film thickness is 1 μm, and a voltage of 24 V is applied, it becomes 0.17 W in 64-bit printing, which is the same level as the electrode of the heating resistor, 0.192 W. And
There is a problem that the print quality is degraded due to the heat generation of the common electrode portion.

The present invention has been made in view of the above problems, and an object thereof is to provide a thermal head capable of preventing heat generation in the common electrode portion.

[0007]

A thermal head according to the present invention has a substrate, a heating resistor provided along one edge of one end of the upper surface of the substrate, and a driving resistor for driving the heating resistor. A plurality of drive ICs are arranged in parallel with the heating resistor at predetermined intervals on a substrate opposite to the edge of the heating resistor, an edge of the one end of the substrate and the heating resistor. And a pattern portion parallel to the end edge and an electrode pattern portion which crosses the heating resistor and is arranged at predetermined intervals, and between the electrode pattern portion and the adjacent drive IC, and the other end portion of the substrate. A common electrode pattern formed of a lead-out pattern portion extending in a direction and the electrode pattern portion are alternately arranged in a permutation, and cross the heating resistor and extend to the side opposite to the one end. Individual electrode pattern In those and a signal wiring pattern for the drive IC is formed on the other end side of the substrate than live IC, the signal wiring pattern portion, provided at least two wiring patterns of the strobe signal,
Each wiring pattern for these strobe signals is connected to the strobe signal terminal of the drive IC at least every other drive IC.

In this thermal head, if there are two strobe signal wiring patterns, each drive IC
Then, every other strobe signal terminal is alternately connected to different wiring patterns for strobe signals. Therefore, when a drive IC drives a heating resistor, the drive ICs on both sides do not drive the corresponding heating resistor. Therefore, the drive IC that is driving
Only the current flows through the drive IC in the lead-out pattern portions of the common electrode pattern portions located at both ends of the drive pattern and the electrode pattern portions connected to the lead-out pattern portions.
That is, as compared with the case where all the drive ICs are operating, the current flowing through the extraction pattern part of the common electrode and the electrode pattern part connected to this extraction pattern part is approximately 1/2.
Becomes Since the electric power is consumed by P = I ² R, if the electric current is halved, the electric power becomes ¼, and the heat generation of the electrode is greatly reduced. Therefore, the heat-sensitive paper does not develop color due to heat generation in the comb-teeth-shaped pieces connected to the extraction pattern portion of the common electrode portion.

[0009]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a plan view of an essential part of a thermal head according to an embodiment of the present invention. In FIG. 1, this thermal head has a heating resistor 2, a common electrode pattern 3, an individual electrode pattern 4, and a drive IC on an upper surface of an insulating substrate 1.
5 (5 _-1 , 5 _-2 , 5 _-3 , ...), and the common electrode pattern 3 is extended so as to cross the pattern portion 30 parallel to the heating resistor 2 and the heating resistor 2. Comb-shaped piece 33,
The drawer pattern portion 31 is integrally configured, and in these points,
There is no difference from the conventional one shown in FIG.

However, in an actual line head, heat is generated.
There are over a thousand dots, and a large number of drive ICs 5 are arranged.
ing. Then, the single drive IC 5 is, for example,
Each is responsible for 64 dots. Therefore one
Sixty-four lead patterns 4 are connected to the IC5.
However, in FIG. 1 and FIG.
), For each single drive IC 5,
Shows the dots and to select these 8 dots
Eight individual lead patterns 4 are arranged and adjacent
Common lead pattern located between drive ICs 5 and 5
Only the comb tooth-shaped piece 33 of No. 3 is directed toward the other end of the insulating substrate 1 (d
Withdrawal pattern 31 toward the live IC) and
The lower end of the drawing pattern 31 is opposed to the heating resistor 2.
Then, a parallel pattern is formed, and the parallel pattern 32 is formed.
Above, drive IC5_-15,_-25, _-3Has implemented ...
It Furthermore, the individual lead patterns 4 have end portions, respectively.
At the pad portion 41 of the drive IC 5 and wire bond
I am running.

In the insulating substrate 1, a signal lead pattern portion 6 for giving or outputting a signal to the drive IC 5 is formed between the drive IC 5 and the edge of the other end portion. The signal lead pattern portion 6 is composed of a lead pattern 61 and an external lead-out terminal 62. Further, a pad 63 for wire bonding is formed on the lead pattern 61, and the pad 63 and the signal terminal 5 of the drive IC 5 are formed.
2 are connected by a bonding wire.

The signal to the drive IC 5 is a clock signal.
Clock signal, data signal, latch signal, strobe signal, power
Source voltage V_DD, GND line, etc., but in FIG.
The drive IC 5 shows five signal terminals. this
The most characteristic feature of the embodiment is that the strobe signal is supplied.
Strobe with two supply systems and different drive ICs 5
Every other signal is strobed.
It In FIG. 1, 61_S1, 61_S2For strobe signal
Lead pattern, 62_S1, 62_S2Is the end for strobe signal
Is a child. Strobe signal lead pattern 61_S1, 6
1_S2Is a wire button for every other drive IC5.
Pad 63 for binding_S1, 63_S2Is equipped with. Figure
Then, drive IC5 on the left end _-1And one drive I
C5_-3The strobe signal read pattern 61_S1The Pa
Dod 63_S1Are connected by wire bonding,
Signal STR₁Is added, but the strike
Lobe signal 61_S2Pad 63_S2Is not provided and is connected
It is not. Conversely, drive IC5_-2In the strobe
Signal lead pattern 61_S2Pad 63_S2Is wire wire
Connected with a strobe signal STR₂Given by
However, the strobe signal 61_S1The Pa
Dod 63 _S1Is not provided, so the strobe signal S
TR₁Cannot be added.

In the thermal head of this embodiment,
Trove signal STR₁OFF, strobe signal STR
₂Assume that is ON. In this case, drive IC
5_-15,_-3Is the strobe signal STR₂Is added
Drive IC5 is not driven because it is not_-2Is driven
It Therefore, drive IC5_-1Left side drawer putter
31_-1To the right side of the drawing pattern 31_-2Current to
Drive IC5_-3Right side drawer pattern (not shown)
From left side of the drawing pattern 31_-3The current difference is
It doesn't flow because it is not twisted. Therefore, drive IC5
_-2The common electrode lead-out pattern 31_-2, 31_-3Electric power
The flow flows. Therefore, drive IC5 _-2All dots of
When ON, drive IC5_-21 / of the total current flowing through
2 for each withdrawal pattern 31_-2And 31_-3Supplied by
Just do it. In this way, even when all dots are turned on,
Apply the current to the drawing pattern of the common electrode pattern
Compared with the case of driving ICs in contact with each other at the same time,
The drawer pattern part, and connect it to this drawer pattern part.
It is possible to reduce heat generation at the crossed part of the electrode pattern.

Further, as in the above example, the drive IC _5-2
If drives the, both ends of dots driven drive IC 5 _-2, since there is no influence of heat generation dots from one side than on the inner side of the dot, but the print tends to be thin,
Since the cross portion connected to the extraction pattern of the common electrode pattern portion generates a weak amount of heat, it functions like a heating dot from one side, so that no white streak occurs at the break of the strobe signal STR.

In the above embodiment, the lead patterns for strobe signals are provided with wire bonding pads for every other drive IC, but the pads are:
Alternatively, each drive IC may be provided and only the connection by wire bonding may be performed every other drive IC. Further, in the above embodiment, the number of strobe signals is two, but in the present invention, there are three or more strobe signals, different strobe signals are sequentially shifted by one with respect to the drive IC, and each strobe signal is three. It may be added repeatedly for each number or more.

[0016]

According to the present invention, at least two strobe signals are applied to the thermal head in which the extraction pattern portion of the common electrode pattern portion is provided between the adjacent drive ICs.
Since the individual drive ICs that are adjacent to each other are driven at the same time, the current flowing through the common electrode pattern portion is reduced to about 1/2, and the power consumed in the common electrode portion is significantly reduced. It is possible to reduce heat generation in the part. Also, with a normal thermal head, due to the problem of power capacity,
For printing with a high print density, a plurality of strobe signals STR are used, several drive ICs are set as one group, and strobes are performed in a divided manner. In this case, dots at both ends have dots that do not generate heat on both right and left sides. Although there is an inconvenience that one side is cooled and does not reach a predetermined size, the present invention solves the problem that one side (outer side) of the dots at both ends is cooled because the common electrode part generates a small amount of heat.

[Brief description of drawings]

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

FIG. 2 is a main part plan view showing a conventional thermal head.

[Explanation of symbols]

2 Heating element 5, 5 _-1 , ... Drive IC 31 _-1 , 31 _-2 Common electrode pattern lead-out pattern 61 Signal wiring pattern portion 61 _S1 , 61 _S2 Strobe signal wiring pattern

Claims (1)

[Claims] 1. A substrate, a heating resistor arranged along one edge of one end of an upper surface of the substrate, and a heating resistor arranged at a predetermined interval for driving the heating resistor, in parallel with the heating resistor.
A plurality of drive ICs are arranged on the substrate opposite to the edge of the heating resistor, a pattern portion parallel to the edge between the edge of the one end of the substrate and the heating resistor, and An electrode pattern portion which is arranged at predetermined intervals so as to cross the heating resistor and the drive IC adjacent to the electrode pattern portion by the electrode pattern portion.
A common electrode pattern portion consisting of a lead-out pattern portion extending in the direction of the other end of the substrate through a space, and the electrode pattern portion are alternately arranged in a permutation in order and crossed with the heating resistor. A thermal head comprising: an individual electrode pattern extending on the side opposite to one end; and a signal wiring pattern portion for a drive IC formed on a substrate on the other end side of the drive IC, wherein the signal wiring At least two wiring patterns for strobe signals are provided in the pattern portion, and at least every other wiring pattern for strobe signals is connected to the strobe signal terminal of the drive IC. Thermal head.