JP2559950B2 - Line type 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 line type thermal head.

[0002]

2. Description of the Related Art FIG. 5 is a side view showing a conventional line type thermal head. In this thermal head, an insulating substrate 72 and a reinforcing plate 73 are placed on an upper surface of an aluminum heat radiating plate 71, and a heating dot 74 and a driving IC 75 are mounted on a wiring pattern of the insulating substrate 72. A flexible board 76 for external circuit connection, one end of which overlaps with the end of the wiring pattern, is arranged on the upper surface of the reinforcing board 73, and the flexible board 76 is provided on a connector 77 provided on the lower surface of the reinforcing board 73. Connected. Further, the insulation cover (wiring pattern) 72 and the flexible substrate 76 overlap the pressure contact cover 7 provided with silicone rubber 78.
9 is arranged, and the press contact cover 79 is fixed to the reinforcing plate 73 with the screw 79a, so that the insulating substrate (wiring pattern)
The 72 and the flexible substrate 76 are in pressure contact with each other.

[0003]

On the insulating substrate (ceramic substrate) of the thermal head, in addition to a dot connection pattern (not shown) for connecting the heating dots and the drive IC, each drive IC has An input signal pattern for connecting to each input signal terminal is formed. As shown in the explanatory view of FIG. 7, the conventional input signal wiring pattern 72a has input signal terminals (for example, a data-in terminal, a power supply terminal, a clock signal terminal, a ground terminal, a strobe terminal, a latch) of each drive IC 75. The input signal patterns (signal terminals) 72a corresponding to the terminals and the data-out terminals) 75a are individually formed. Therefore, it is necessary to similarly form the wiring pattern 76a including a plurality of signal wirings also on the flexible substrate 76 connected to the input signal pattern 72a. However, in order to form the wiring pattern 76a corresponding to the input signal pattern 72a individually drawn from each input signal terminal 75a of each drive IC 75 on the flexible substrate 76, each signal line is not crossed. Need to wire to. Therefore, conventionally, for example, through holes are formed in the flexible substrate 76, and the wiring patterns 76a are formed on both front and back surfaces.
However, the flexible substrate 76 is expensive, that is, the thermal head is expensive.

The flexible substrate 76 is formed to have substantially the same length as the insulating substrate 72, and the input signal wiring pattern 72 a of the insulating substrate 72 is arranged in parallel with the heating dots 74.
The upper part is pressed in a polymer state. However, since there are many wiring connection points, as shown in FIG. 6, a large number of screws 79a must be fixed by pressure welding, which is disadvantageous in that the pressure welding operation takes time and the pressure welding reliability is deteriorated. In addition, since the fixing range is wide, it is difficult to fix the line type thermal head with solder as in JP-A-60-107363.

The present invention solves the above problems, and
The purpose of the present invention is to provide an inexpensive thermal head that can reduce warpage due to the difference in coefficient of thermal expansion and the like, and can be easily connected by soldering and has high connection reliability by connecting only both ends.

[0006]

A thermal head according to the present invention comprises a heating dot and a drive IC, and a dot connection pattern for connecting the heating dot and the drive IC and each input of each drive IC. While forming an input signal wiring pattern commonly connected to the signal terminal, an insulating substrate in which the derivation terminals of the input signal wiring pattern are arranged at both ends of one side, and the derivation terminal and the external derivation member. It is composed of a soldered soldered portion.

In the thermal head having such a structure, a glass epoxy substrate having a wiring pattern corresponding to the lead-out terminal of the insulating substrate on one side, a single-sided flexible piece having a wiring pattern corresponding to the lead-out terminal of the insulating substrate on one side, etc. The external lead-out member and the lead-out terminal of the insulating substrate are connected by soldering. The input signal wiring pattern of the insulating substrate is
The drive ICs are commonly connected to the input signal terminals of the drive ICs, and the lead terminals of the signal input wiring pattern are arranged at both ends of the insulating substrate. Therefore, the external lead-out member may be a small piece having a size corresponding to the lead-out terminal, that is, a small piece corresponding to both ends of one side of the insulating substrate, and is an inexpensive one having a wiring pattern only on one surface. good. Further, the connection portion of this external lead-out member only needs to be arranged corresponding to the lead-out terminals provided at both ends of the insulating substrate, and therefore the connection reliability is improved and the conventional pressure contact tightening (when screw tightening) ) Can eliminate the distortion that may occur.

[0008]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a plan view of a thermal head substrate used for implementing the present invention. The thermal head substrate (insulating substrate) 1 has heating dots (dot rows) 11 on one surface.
And a plurality of drive ICs (20 ICs in the embodiment)
2 and are implemented. The insulating substrate 1 has heating dots 11
, A common pattern 31 for connecting the heating dots 11, a dot connecting pattern (not shown) for connecting the heating dots 11 to the drive IC 2, and an input signal wiring pattern 3 for connecting each input signal terminal 21 of the drive IC 2 And form.

FIG. 2 is an enlarged explanatory view of an essential part showing the input signal wiring pattern 3 of the insulating substrate (ceramic substrate) 1. Each drive IC 2 has a DI (data in) terminal 21 as an input signal terminal 21 in addition to a dot terminal.
a, 5V (power supply) terminal 21b, CLK (clock signal)
Terminal 21c, GND (ground) terminal 21d, STR (strobe signal) terminal 21e, LA (latch signal) terminal 2
Seven terminals, 1f and a DO (data out) terminal 21g, are formed. On the other hand, the input signal wiring pattern 3 of the insulating substrate 1 is provided with a COM (common) pattern 31 and a GND (ground) pattern 32 linearly arranged on one side side on the outer periphery of the insulating substrate 1, and the drive IC 2 5V pattern 33, DI pattern 34, clock pattern 35 and latch pattern 36 are respectively provided between the ground pattern 32 and the ground pattern 32, and the strobe pattern 37 is linearly arranged so as to pass through the lower side of each drive IC 2. ing. Then, the data-in / out connection pattern 3 for connecting the data-out terminal 21a and the data-in terminal 21g of the adjacent drive ICs 2 to each other
8 is provided.

Each input signal terminal 21 of each drive IC is connected to the corresponding input signal wiring pattern 3 by wire bonding. That is, the data-in terminal 21 a of the drive IC 2 located on one end side of the insulating substrate 1 is connected to the DI pattern 34 by the wire bonding 34.
and the 5V terminal 21b is 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 32a. Further, the strobe terminal 21e is connected to the STR pattern 37 by wire bonding 37a, and the latch terminal 21f is L.
It is connected to the A 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.

As described above, the input signal pattern 3 on the insulating substrate 1 has the input signal terminal 21 of each drive IC 2.
1 and 2, the lead-out ends 3A and 3B of the input signal pattern 3 are arranged as lead-out terminals at both ends of one side of the insulating substrate 1, as shown in FIGS. . The lead-out terminal 3A is located at 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 provided 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 STR3 lead-out terminal 37e are sequentially arranged. This means that 20 drive ICs 2 are divided into 4 groups of 5 drives each, and one group (5 drive I
It is set so that the strobe signal is input for each C).

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, the ground terminal 21d, the strobe terminal 21e, the latch terminal 21f, and the data-out terminal 21g) 21 are commonly connected by the common input signal wiring pattern 3 formed on the insulating substrate 1 via wire bonding (34a ... 38a). Has been done. 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 points of the signal line is extremely reduced, which can improve the simplicity of connection work and the reliability of connection.

FIG. 3 is an exploded plan view showing an embodiment of the thermal head of the present invention. This thermal head includes an insulating substrate 1 shown in FIG. 1 and two single-sided flexible pieces 4 each having a wiring pattern corresponding to each of the lead terminals 3A and 3B of the insulating substrate (input signal wiring pattern 3) 1 on one side. 4a, and a single-sided glass epoxy substrate 5 also having a wiring pattern on one side corresponding to the lead terminals 3A and 3B.

The single-sided flexible piece 4 has the lead-out terminal 3 described above.
A common line 41 connected to the common pattern 31 at one end, a 5V line 42 connected to the 5V lead terminal 33b, and a DI connected to the DI lead terminal 34b at one end.
Line 43, CLK line 44 connected to CLK lead-out terminal 35b, LA line 4 connected to LA lead-out terminal 36b
5, and GND connected to the ground pattern 32 at the other end
A line 46 is formed. Similarly, the single-sided flexible piece 4A is a piece having a size corresponding to the lead-out terminal 3B, and has one end connected to an earth line 41a connected to the earth pattern 32,
STR1 line 42 connected to STR1 lead terminal 37b
a, STR2 line 43a connected to STR2 lead terminal 37c, STR3 line 44a connected to STR3 lead terminal 37d, STR connected to STR4 lead terminal 37e
Four lines 45a and a common line 46a connected to the common pattern 31 are formed.

The single-sided glass epoxy substrate 5 has a wiring pattern 5 corresponding to the lead-out terminals 3A and 3B of the insulating substrate 1.
1 are provided on one side, and signal lines starting from both ends are led out to a lead-out terminal 52 at the center of the length. That is, the lead-out terminal 52 is the COM terminal 52 in the figure (from the left side).
a, DI terminal 52b, 5V terminal 52c, CLK terminal 52
d, LA terminal 52e, GND terminal 52f, GND terminal 5
2g, STR1 terminal 52h, STR2 terminal 52i, ST
R terminal 52j, STR3 terminal 52k, COM terminal 52l
Are arranged in order. Then, the lead-out terminal 52 is connected to the connector 63.

In this thermal head, as shown in the side view of FIG. 4, the insulating substrate 1 and the glass epoxy substrate 5 are placed on the upper surface of the heat dissipation plate 61, and the insulating substrate (input signal pattern 3) is placed.
The lead-out terminals 3A and 3B of No. 1 and the signal wiring end faces located at both ends of the wiring pattern 51 of the glass epoxy substrate 5 are butted.
The single-sided flexible pieces 4 and 4A are superposed on the upper surfaces of the abutting surfaces, respectively. The joint surfaces of the one-sided flexible pieces 4 and 4A and the insulating substrate 1 and the joint surfaces of the one-sided flexible pieces 4 and 4A and the glass epoxy substrate 5 are soldered. The lead-out terminal 52 of the glass epoxy substrate 5 is connected to the connector 63. Therefore, the signal input pattern 3 on the insulating substrate 1 and the wiring pattern 51 on the single-sided glass epoxy substrate 5
To connect with the flexible substrate 4 (4A), it is sufficient to solder only the two lead terminals 3A, 3B at both ends of the insulating substrate (input signal pattern 3) 1 through the single-sided flexible strips 4, 4A. ) And the glass-epoxy substrate 5 may have a wiring pattern provided on only one surface. Therefore, an expensive flexible substrate with a double-sided wiring as in the related art is not required, and an inexpensive thermal head can be provided.
Further, since it is sufficient to connect the solder only to both ends of the insulating substrate 1 at two places, the connection work is easy and the reliability of the connection is not improved. You don't have to. Also, since only the both ends are soldered, the occurrence of "warpage" due to the difference in the coefficient of thermal expansion can be reduced.

[0017]

According to the present invention, the lead-out terminals provided at both ends of one side of the insulating substrate of the input signal wiring pattern commonly connected to the respective input signal terminals of each drive IC, and the external lead-out. Since it is decided to connect the members by soldering, it is sufficient to solder only both ends of the insulating substrate,
The connection work by soldering is easy, the connection reliability can be improved, and it is possible to provide an inexpensive line-type thermal head, and further, it is possible to reduce the occurrence of "warpage" due to the difference in thermal expansion coefficient. Further, since the lead terminals of the input signal wiring pattern are provided at both ends of one side of the insulating substrate, that is, the power supply line and the GND line of the input signal wiring pattern are taken at both ends of the substrate. Therefore, compared with the case where the lead-out terminal is provided only at one end, it is possible to prevent the voltage drop of the power supply line and the voltage rise of the GND line, and when a large current flows when driving a large number of heating dots at one time. It is possible to realize a line-type thermal head with low power consumption without causing uneven printing density.

[Brief description of drawings]

FIG. 1 is a plan view of an insulating substrate used in a thermal head according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view of a main part of the insulating substrate.

FIG. 3 is an exploded plan view showing a thermal head according to an embodiment of the present invention.

FIG. 4 is a side view of the thermal head of the same embodiment.

FIG. 5 is a side view showing a conventional thermal head.

FIG. 6 is a plan view of a conventional thermal head.

FIG. 7 is a plan view illustrating a main part of a conventional thermal head.

[Explanation of symbols]

 1 Insulation board 2 Drive IC 3 Input signal wiring pattern 3A, 3B Lead-out terminal 4, 4B Single-sided flexible piece 5 Glass epoxy board

Claims (1)

(57) [Claims] 1. A dot connection pattern for connecting a heating dot and a drive IC, and an input signal wiring pattern commonly connected to each input signal terminal of each drive IC. a thermal head consisting of bets to form a, an insulating substrate having disposed on both ends of one side of the lead terminal for the input signal wiring pattern, and the said leading terminal and the external lead member soldered solder connection.