JPH0732054Y2 - Thermal head feed line connection structure - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a feed line connecting structure for a thermal head having good connection workability.

(B) Conventional Technology FIG. 4 is a plan view showing an example of an electrode pattern of a conventional thermal head.

The thermal head has a plurality of individual electrodes 62, a common electrode 63, and a heating resistor 64 formed on the upper surface of an insulating substrate (head substrate) 61. In this type of thermal head, power is supplied from both ends (“A” and “A” in the figure) of the common electrode 63 when used. However, in this power feeding method, the difference in resistance value from the power feeding point of the common electrode 63 to each heating resistor 64 cannot be ignored, and the heating resistors located at the central portion (near B) from the heating resistors 64 located at both ends. In the body 64, the distance of the common electrode 63 from the feeding point is longer, the electric resistance becomes larger accordingly, and the voltage drop becomes larger. As a result, the heating resistor 64 located at the center is
However, there is a disadvantage that the print density decreases.

Therefore, in recent years, a thermal head as shown in FIG. 5 has been implemented. In this thermal head, a plurality of individual electrodes 62 and a heating resistor 64 are provided on the upper surface (front surface) of a head substrate 61, while the common electrode 63 is extended from the end portion of the upper surface on the heating resistor 64 side to the back surface (lower surface). Have been deployed. Then, a lead wire 67 is connected between the common electrode 63 on the back surface and the common electrode lead pattern portion 66 of the external circuit connecting flexible substrate 65 to establish conduction. According to this feeder connection method,
The common electrode 63 is provided on the entire back surface of the head substrate 61,
Since it is a flat electrode, the electric resistance is small, and the voltage drop at the point "B" as shown in FIG. 4 does not occur, and the printing accuracy can be secured.

(C) Problems to be Solved by the Invention In the above-described power supply line connection structure for the thermal head shown in FIG. 5, by soldering the lead wires, the common electrode provided on the back surface of the head substrate and the flexible substrate for external circuit connection are provided. (Common electrode lead pattern portion). Therefore, the common electrode provided on the head substrate requires a solderable pattern, for example, a pattern of Ag-Pd, which is disadvantageous in that it is expensive. Also, since the lower surface of the head substrate is usually supported by a heat sink,
Since the work of soldering the lead wire is troublesome, there is a disadvantage that the number of steps is increased, for example, in order to pull out the lead wire to the outside, it is necessary to provide a lead wire escape groove in the heat sink.

An object of the present invention is to solve the above problems, and to provide a power supply wire connection structure for a thermal head in which a voltage drop does not occur and a common electrode can be connected with a simple configuration.

(D) Means and Actions for Solving the Problems The power supply line connection structure of the thermal head of the present invention is provided with a heating resistor array and individual electrodes on the upper surface, and a common electrode connected from the upper surface to the back surface. A structure for connecting a power supply line to a thermal head substrate (1), which has individual lead patterns corresponding to the individual electrodes, and common lead patterns corresponding to the common electrodes are provided at both ends in the heating resistor row direction. A first flexible substrate (5) having the same, and a conductor layer corresponding to a common electrode of the thermal head substrate, and from this conductor layer corresponding to a common lead pattern of the first flexible substrate, a heating resistor column direction. A second flexible substrate (2) having extension legs respectively extending at both ends of the thermal head substrate. The individual flexible electrodes of the plate are pressure-contact connected, the second flexible substrate is arranged on the back surface side of the thermal head substrate, the conductor layer of the second flexible substrate is pressure-connected to the common electrode of the thermal head substrate, and The drawer leg portion of the flexible substrate is pressure-contacted to the common lead pattern of the first flexible substrate.

In this thermal head feed line connection structure, the individual lead patterns of the first flexible substrate and the individual electrodes of the thermal head substrate are in contact with each other, and the conductor layer of the second flexible substrate is the lower surface of the thermal head substrate. Of the second flexible printed circuit board facing the common electrode of
The surface is in contact with the common lead pattern of the first flexible substrate. Then, in this contact state, the individual lead patterns of the first flexible substrate, the individual electrode contact faces of the thermal head substrate, and the common lead pattern contact faces of the first and second flexible substrates are used for pressure contact, for example. With a metal cover (a full-face cover that is pressed through silicon rubber),
Pressed and fixed.

Thus, the common electrode of the thermal head substrate can be electrically connected to the common lead pattern of the first flexible substrate for external circuit connection through the second flexible substrate for connecting the common electrode by a very simple operation. Therefore, the conventional work of soldering the lead wire to the connection of the common electrode pattern is eliminated.

(E) Embodiment FIG. 2 is an enlarged perspective view of a main part showing a power supply line connection structure of a thermal head according to the present invention.

In the pattern connection structure of the thermal head, the thermal head substrate 1 is provided with an individual electrode and a heating resistor on the upper surface, and a common electrode is continuously provided from the upper surface to the lower surface, and a conductor layer is connected to the common electrode of the thermal head substrate 1. The pull-out leg portion is composed of the common electrode connecting flexible substrate (second flexible substrate) 2 connected to the common electrode lead pattern portion 51 of the external circuit connecting flexible substrate (first flexible substrate) 5. It

The thermal head substrate 1 has the same structure as that shown in FIG. 5 in which individual electrodes, heating resistors (not shown) are formed on the upper surface, and a common electrode is formed from the upper surface to the lower surface (see FIG. 3). It is placed and fixed on the upper surface of. The heat dissipation plate 3 mounts the thermal head substrate 1 on one end side of the upper surface, and has a notch 31 of a width corresponding to a lead-out leg 21 of a flexible substrate 2 for common electrode connection, which will be described later, at a certain length on the other end side. It is provided. In addition, on the upper surface of the other end of the heat dissipation plate 3 (the drawer leg 21 drawer side),
The reinforcing plate 4 is superposed, and the external circuit connecting flexible substrate 5 is placed on the reinforcing plate 4. This external circuit connecting flexible substrate 5 is provided with an individual electrode lead pattern portion 52 at the center of the surface and a common electrode lead pattern portion at both ends.
51 is provided. Then, the common electrode lead pattern portion 51
Is located on the front side of the cutout portion 31 of the heat dissipation plate 3, and the protruding tip portion (individual electrode lead pattern portion 52) of the central portion is joined to the upper surface individual electrode 11 of the thermal head substrate 1 which is at the equal height position. It is set to conduct electricity. As shown in FIG. 3, the flexible substrate 5 for external circuit connection has a front side conductor (common electrode lead pattern portion 5) on the base film 5a.
1) 5b, the insulating film 5c on the front conductor 5b, and the back conductor (individual electrode lead pattern part 5
2) 5d, an insulating film 5e was polymerized under the back conductor 5d 5
It is formed in a layered structure.

The feature of this embodiment is that the common electrode connecting flexible substrate 2 for electrically connecting the common electrode 12 provided on the back surface of the thermal head substrate 1 and the external circuit connecting flexible substrate (common electrode lead pattern portion 51) 5 is provided. Is.

FIG. 1 is a partially omitted perspective view showing a flexible substrate 2 for connecting a common electrode.

The common electrode connecting flexible substrate 2 is formed in a U-shape in a plan view, which includes two facing leg portions 21 for pulling out and a fixing portion 22 that connects the two leg portions 21. The flexible substrate 2 for connecting the common electrode is formed on the conductor layer 2c.
The lower surface has a three-layer structure in which insulating films 2a and 2b are polymerized. In the conductor layer 2c located in the middle, the lower surface is exposed for a certain length on the side of the drawing leg portion 21 (adjacent to the lower insulating film 2b), and the upper surface is exposed on the side of the fixed portion 22 (from the upper insulating film 2a). Appearance) is set. The fixed portion 22 side of the conductor layer 2c has a size substantially corresponding to the width of the thermal head substrate 1, and the lead-out leg portion 21 side corresponds to the common electrode lead pattern portion 51 of the external circuit connecting flexible substrate 5. The size (width) is set.

When the thermal head substrate 1 and the external circuit connecting flexible substrate 5 are connected using the common electrode connecting flexible substrate 2 having such a configuration, it is carried out as shown in FIG. That is, in this common electrode connecting flexible substrate 2, the fixing portion 22 side is pressure-bonded and fixed between the thermal head substrate 1 and the heat dissipation plate 3. At this time, the head substrate 1
Back side common electrode 12 and flexible substrate 2 for common electrode connection
The fixed portion 22, that is, the exposed surface (upper exposed surface) of the conductor layer 2c is completely in contact with and electrically connected. The common electrode 12 is provided on the entire back surface of the head substrate 1, and the voltage drop phenomenon of the heating resistor (not shown) hardly occurs.

Furthermore, the lead-out leg portion 21 is pulled out from the head substrate 1 through the cutout portion 31 of the heat dissipation plate 3 and contacts the upper surface of the common electrode lead pattern portion 51 of the external circuit connecting flexible substrate 5. That is, the lower surface protruding portion of the conductor layer 2c located at the tip of the lead-out leg portion 21 is connected to the common electrode lead pattern portion 51 of the external circuit connecting flexible substrate 5.

Further, the individual electrode lead pattern portion 52 of the external circuit connecting flexible substrate 5 is in contact with the upper surface of the upper surface individual electrode 11 of the thermal head substrate 1 and is electrically connected as in the conventional case. Then, these connection states, that is, the individual electrodes of the head substrate 1
11 and the individual electrode lead pattern portion 52 of the external circuit connecting flexible substrate 5, and the connection between the conductor layer 2c of the common electrode connecting flexible substrate 2 and the common electrode lead pattern portion 51 of the external circuit connecting flexible substrate 5. Is fixed by pressure using, for example, a conventionally used pressure-contact metal cover (metal cover pressure-contacted via silicon rubber).

Thus, the individual electrode 11 of the head substrate 1 is connected to the individual electrode lead pattern portion 52 of the external circuit connecting flexible substrate 5 as in the conventional case, and the common electrode 12 of the thermal head substrate 1 is connected.
Can be electrically connected to the common electrode lead pattern portion 51 of the external circuit connecting flexible substrate 5 through the common electrode connecting flexible substrate 2 by an extremely simple operation. Therefore, the soldering work of connecting the common electrode pattern through the lead wire is completely unnecessary.

(F) Effect of the Invention According to the invention, as described above, the thermal head substrate having the individual electrodes on the upper surface and the common electrode on the lower surface is provided with the second common electrode for connecting the common electrode to the lower common electrode of the thermal head substrate.
Since the conductor layer of the flexible substrate is pressure-bonded and fixed, and the extraction leg portion is connected to the common electrode lead pattern portion of the first flexible substrate for external circuit connection for connecting to the individual electrode, the second flexible The conductor layer of the substrate is pressure-bonded and fixed between the thermal head substrate and the heat radiating plate, and the extraction leg portion is connected to the common electrode lead pattern portion of the first flexible substrate. Then, the individual electrodes of the thermal head substrate and the individual lead patterns of the first flexible substrate, and the common lead pattern of the first flexible substrate and the second flexible substrate are press-contacted and fixed by, for example, a metal cover for press-contacting. A pattern for power supply is connected during work. Therefore, the voltage drop phenomenon of the heating resistor does not occur, and the conventional lead wire soldering work and the formation of a soldering pattern are unnecessary, and the excellent effect of achieving the object of the invention is achieved. .

[Brief description of drawings]

FIG. 1 is a perspective view showing a common electrode connecting flexible substrate, FIG. 2 is an enlarged perspective view of a principal part showing a pattern connecting structure of an embodiment thermal head, and FIG. 3 is a pattern connecting structure of an embodiment thermal head. FIG. 4 is a plan view showing an electrode pattern of a conventional thermal head, and FIG. 5 is a perspective view showing a pattern connection structure of a thermal head which has been recently implemented. 1: Thermal head substrate, 2: Flexible substrate for common electrode connection, 5: Flexible substrate for external circuit connection, 11: Individual electrode, 12: Common electrode.

Claims (1)

[Scope of utility model registration request] 1. A structure for connecting a power supply line to a thermal head substrate, wherein a heating resistor array and individual electrodes are arranged on the upper surface, and a common electrode is provided continuously from the upper surface to the rear surface, the structure corresponding to the individual electrodes. And a conductor layer corresponding to the common electrode of the thermal head substrate, and a first flexible substrate having common lead patterns corresponding to the common electrode at both ends in the heating resistor array direction. And a second leg having lead-out portions extending from the conductor layer at both ends in the heating resistor row direction corresponding to the common lead pattern of the first flexible substrate.
A flexible substrate, the individual lead patterns of the first flexible substrate are pressure-contacted to the individual electrodes of the thermal head substrate, and the second flexible substrate is arranged on the back surface side of the thermal head substrate. The conductor layer of the first head is pressed and connected to the common electrode of the thermal head substrate, and the pull-out leg portion of the second flexible substrate is connected to the first electrode.
The power supply line connection structure of the thermal head, which is connected by pressure contact to the common lead pattern of the flexible substrate of.