JP2559951B2 - Thermal head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head.

[0002]

2. Description of the Related Art FIG. 3 is a side view showing a conventional thermal head. This thermal head has an aluminum heat sink 71
The insulating substrate 72 and the reinforcing plate 73 are placed on the upper surface of the substrate, and the heating dots 74 and the drive IC 75 are mounted on the wiring pattern of the insulating substrate 72. Then, on the upper surface of the reinforcing plate 73, a flexible substrate 76 for connecting an external circuit, one end of which is overlapped with the end of the wiring pattern, is provided, and the flexible substrate 76 is provided on a connector 77 provided on the lower surface of the reinforcing plate 73. Connected. Further, a press-contact cover 79 provided with a silicone rubber 78 is disposed on the overlapping portion of the insulating substrate (wiring pattern) 72 and the flexible substrate 76,
By fixing the press-contact cover 79 to the reinforcing plate 73 with a screw 79a, the insulating substrate (wiring pattern) 72 and the flexible substrate 76 are pressed against each other.

On the insulating substrate (ceramic substrate) of this type of thermal head, in addition to a dot connection pattern (not shown) for connecting the heating dots and the drive IC,
An input signal pattern for connecting to each input signal terminal of each drive IC is formed. This input signal wiring pattern 72a is, as shown in the explanatory view of FIG. 4, each input signal terminal (for example, data-in terminal, power supply terminal, clock signal terminal, strobe terminal, latch terminal, etc.) 75a of each drive IC 75. The input signal pattern (signal wiring) 72a corresponding to is formed individually.

[0004]

In the conventional thermal head described above, the input signal wiring pattern and the lead-out terminal formed on the insulating substrate are individual for each drive IC, and the ground pattern and the lead-out terminal are provided. Is also formed separately as in the case of the input signal pattern and the like. Therefore, there is a problem in that only the ground signal pattern cannot be made thick (thick), and a large amount of current cannot flow.

The present invention has been made in view of the above problems, and an object thereof is to provide a thermal head capable of thickening (thickening) the ground pattern and allowing a large amount of current to flow through the heating dots.

[0006]

In the thermal head according to the present invention, the heating dots and the driving ICs are connected to the insulating substrates arranged in parallel in the longitudinal direction, respectively. A dot connection pattern, a ground pattern, and an input signal wiring pattern common to each input signal terminal of each drive IC, and a heating dot is formed on the ground pattern with the drive IC as a reference. The input signal wiring pattern is formed between the ground pattern and the drive IC, and is formed along the edge of the long side opposite to the one to be arranged, and the lead terminal of the input signal wiring pattern is formed. It is arranged at both ends of the long side adjacent to both ends of the ground pattern.

In this thermal head, the ground pattern is formed along the edge of the insulating substrate, and the input signal wiring pattern is arranged between the ground pattern and the drive IC. It can be made wide or thick, and even if a relatively large current is applied to the heating dot, this is not limited by the thickness of the ground pattern.

[0008]

1 is a plan view showing a thermal head according to an embodiment of the present invention. Thermal head substrate (insulating substrate)
1 has a heating dot (dot row) 11 on one side and a plurality of drive ICs (20 ICs in the embodiment) 2 mounted thereon. On the insulating substrate 1, the common pattern 31 connected to the heating dot 11 and the heating dot 11 are connected to the drive IC.
A dot connection pattern (not shown) to be connected to No. 2 and an input signal wiring pattern 3 for connecting each input signal terminal 21 of the drive IC 2 are formed.

FIG. 2 is an enlarged explanatory view of the essential parts showing the input signal wiring pattern 3, the ground pattern 32, etc. of the insulating substrate (ceramic substrate) 1. In addition to the dot terminals, each of the drive ICs 2 has a DI (data-in) terminal 21a, a 5V (power) terminal 21b, and a CLK as signal terminals 21.
(Clock signal) terminal 21c, GND (ground) terminal 2
1d, STR (strobe signal) terminal 21e, LA (latch signal) terminal 21f, and DO (data out) terminal 2
Seven terminals of 1 g are formed. On the other hand, the insulating substrate 1 has a COM (common) pattern 31 on the outer periphery of the insulating substrate 1.
And G arranged linearly on the side edge on the side opposite to the side where the heat-generating dots are arranged, with reference to each drive IC.
ND (earth) pattern 32 is provided, and drive IC 2
5V pattern 33, D between the ground pattern 32 and the ground pattern 32
The I pattern 34, the clock pattern 35, and the latch pattern 36 are provided, and the strobe pattern 37 is linearly arranged so as to pass through the lower side of each drive IC 2. Then, a data-in / out connection pattern 38 for connecting the data-out terminal 21a and the data-in terminal 21g of the adjacent drive IC 2 to each other is provided.

Each input signal terminal 21 of each drive IC is connected to the corresponding input signal wiring pattern 3 and ground pattern 32 by wire bonding. That is, the data-in terminal 21 a of the drive IC 2 located on the one end side of the insulating substrate 1 is connected to the DI pattern 34.
To the 5V terminal 21b.
Are connected to the 5V pattern 33 by wire bonding 33a. Similarly, the clock terminal 21c is connected to the CLK pattern 35 by wire bonding 35a, and the ground terminal 21d is connected to the GND pattern 32 by wire bonding 3
It is connected by 2a. Further, the strobe terminal 21e is S
The TR pattern 37 is connected by wire bonding 37a, and the latch terminal 21f is connected to the LA pattern 36 by wire bonding 36a. The data-out terminal 21g is connected to the data-in / out pattern 38 via the wire bonding 38a, and is connected to the data-in terminal of the adjacent IC 2a. In this way, the input signal pattern 3 of the insulating substrate 1 is formed as a common connection pattern in each input signal terminal 21 of each drive IC 2, and the lead-out ends 3A and 3B of this input signal pattern 3 are
As shown in FIGS. 1 and 2, the lead-out terminals are arranged at both ends of one side of the insulating substrate 1.

The lead-out terminal 3A has one end on one side of the insulating substrate 1, that is, the ground pattern 32 and the common pattern 3.
5V lead terminal 33b and DI lead terminal 34 between
b, the CLK derivation terminal 35b, and the LA derivation terminal 36b are arranged in this order. Further, as shown in FIG. 1, the lead-out terminal 3B is located between the other end of the insulating substrate 1 on one side, that is, between the ground pattern 32 and the common pattern 31, and the STR1 lead-out terminal 37b, the STR2 lead-out terminal 37c, and the STR3. The lead-out terminal 37d and the STR lead-out terminal 37e are sequentially arranged.
This is such that 20 drive ICs 2 are divided into 4 groups every 5 drive ICs, and a strobe signal is inputted for each group (5 drive ICs).

In the thermal head having such a configuration, each input signal terminal (data-in terminal 21a, power supply terminal 21b, clock signal terminal 21) of each drive IC 2 is
c, strobe terminal 21e, latch terminal 21f, etc.) 21
However, the wire bonding (34a ... 3) is performed by the common input signal wiring pattern 3 formed on the insulating substrate 1, respectively.
Commonly connected via 8a). The lead terminals 3A and 3B of the common connection pattern 3 are separately arranged at both ends of one side of the insulating substrate 1. Therefore, a connector may be directly connected to each drive IC 2 and data input from an external circuit may be directly input to the lead-out terminals 3A and 3B located at the both ends. That is, it is not necessary to use an expensive flexible board having double-sided wiring, which has the same length as the insulating board 1 and has signal lines corresponding to a large number of individually extracted input signal terminals as in the conventional case. Not only that, the number of connection pressure contact points of the signal line is extremely reduced, and the simplicity of the pressure contact work and the pressure contact reliability can be improved. When connecting the connector directly to the lead-out terminals 3A and 3B,
It can be fixed by soldering instead of pressure welding.

[0013]

According to the present invention, the ground pattern is formed along the edge of the long side of the insulating substrate, the input signal wiring pattern is arranged between the ground pattern and the drive IC, and the input signal is formed. Since the lead-out terminals of the wiring pattern for wiring are arranged at both ends of the long side adjacent to both ends of the ground pattern, the ground pattern can be made wider or thicker (thicker), and the current generated in the heating dot is correspondingly larger. Can be flushed. It is also possible to dispose a ground pattern under the drive IC, but if the wiring is made thick to increase the current, the IC will be tilted when mounting the IC, and there will be the inconvenience that wire bonding will not be successful.
In the present invention, such inconvenience does not occur. Moreover,
When a large number of thermal head substrates are to be cut from a large substrate, the conventional one is susceptible to chipping at the edge, but in the present invention, the ground pattern is formed along the edge of the long side. This also has the effect that chipping is less likely to occur. Further, since the lead terminals of the input signal wiring pattern are arranged at both ends of the long side adjacent to both ends of the ground pattern, that is, the power supply line and the GND of the input signal wiring pattern are arranged.
Since the line is taken at both ends (2 places) of the board, it is possible to prevent the voltage drop of the power supply line and the voltage rise of the GND line, as compared with the case where the lead-out terminal is provided only at one end (1 place). It is possible to realize a thermal head of low power consumption without causing print density unevenness when a large current flows when driving a large number of heating dots at one time. Furthermore, the insulating substrate of the thermal head divides a large substrate, and if a wiring pattern is formed at the end of the substrate, the wiring pattern may be cracked when the substrate is divided by breaking, In the case of a narrow input signal wiring pattern, the pattern may be chipped, but in the present invention, a wide ground pattern is formed especially along the edge of the long side of the insulating substrate. It is possible to prevent such an inconvenience.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of a main part showing an input signal wiring pattern of the thermal head of the embodiment.

FIG. 3 is a side view showing a conventional thermal head.

FIG. 4 is a plan view illustrating a main part of a conventional thermal head.

[Explanation of symbols]

 1 Insulating substrate 2 IC for drive 3 Wiring pattern for input signal 3A, 3B Derivation terminal 32 Ground pattern

Claims (1)

(57) [Claims] 1. A heating dots and a drive IC for is longitudinally into the insulating substrate arranged parallel to each dot connecting patterns of order to connect the heating dots and a drive IC for the earth pattern, the An input signal wiring pattern common to each input signal terminal of the drive IC is formed, and the ground pattern is formed on the long side opposite to the side where the heating dots are arranged with reference to the drive IC. The input signal wiring pattern is arranged between the ground pattern and the drive IC.
In addition, the lead-out terminal of the input signal wiring pattern is grounded.
The thermal head is arranged at both ends of the long side adjacent to both ends of the thermal head.