JP2883681B2 - Conductor connection structure of thermal head array - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lead wire connecting structure for a thermal head array used in a thermal recording apparatus.

[Prior Art] As prior art of the present invention, as a patent application filed by the same applicant as the present applicant, Japanese Patent Application No. 1-171983, entitled "Connecting structure of thermal head array wires", July 5, 2001 There is a prior application).

FIG. 3 is a connection diagram showing the structure of a thermal head array, in which (1) is a thermal head array, and (2)
Is a shift register, (3) is a latch, (4) is a driver, (5) is a power supply, (7) is a switch, (70) and (7)
1) and (72) are contacts of the switch (7). The power supply connected to the contact (71) is temporarily called an A-phase power supply, and the power supply connected to the contact (72) is temporarily called a B-phase power supply.

The shift register (2), the latch (3), and the driver (4) are often collectively configured as an IC, and are therefore referred to as a control circuit IC (6).

(8-1), (8-2)... Are reverse current blocking diodes, (9-1), (9-2)... Are power source side wiring patterns, (10-1), (10). -2) are ground-side wiring patterns.

A data input line and a clock signal line are connected to the shift register (2), a load signal line is connected to the latch (3), and a strobe line is connected to the driver (4). These are called control lines. However, these control lines are omitted in FIG.

Normally, the control circuit IC (6) is divided into a plurality of ICs, and each IC
There is a conductor connecting the ground point of the power supply (5) to the negative terminal of the power supply (5), but this conductor is also omitted in FIG.

When the power supply is not separated into the A phase and the B phase, the connection is as shown in FIG. 4, the same reference numerals as those in FIG. 3 denote the same or corresponding parts, (50) denotes a power supply conductor, and (60) denotes a ground conductor.

Thermal head array (1), control circuit IC (6), backflow prevention diodes (8-1), (8-2), power supply side wiring patterns (9-1), (9-2) ... , Ground-side wiring patterns (10-1), (10-2) ..., conductor patterns to be connected to the A-phase power supply and B-phase power supply or the power supply conductor (50), conductors to be connected to the ground conductor (60) The pattern and the control line pattern are formed on a ceramic substrate to constitute a thermal head substrate. A conductor pattern connected to the pattern on the ceramic substrate and connecting the pattern to an external circuit is formed on a flexible substrate as a relay substrate.

However, only the pattern of the power supply conductor (50) (the pattern of the A-phase power supply conductor and the B-phase power supply conductor in the case of the configuration shown in FIG. 3) and the pattern of the grounding conductor (60) are formed on the flexible substrate. In this case, the conductor resistance is large, and the quality of recording is deteriorated. Therefore, a bus bar having a small conductor resistance is connected in parallel to these patterns to reduce the conductor resistance.

FIG. 5 is a cross-sectional view showing the structure of the prior application, in which (11) and (12) are bus bars having low conductive resistance, (14) and (15) are conductive rubber, and (16) is a conductive rubber. A flexible substrate, (18) is a ceramic substrate, (19) is a heat sink, (20) is a holding bracket, and (21) is a screw. Fifth
The example shown in the figure shows the connection of the power-supply-side flexible board (16) in the case of having an A-phase power supply and a B-phase power supply.

The wiring patterns on the upper surface of the flexible substrate (16) include those connected to the A-phase power supply via the bus bar (11) and those connected to the wiring pattern on the lower surface via the through holes. The patterns include those connected to the wiring pattern on the ceramic substrate (18) and those connected to the B-phase power supply via the bus bar (12).

The busbars (11) and (12) are formed of a copper plate to reduce the electric resistance, and the holding metal (20) ensures contact between the busbar and the flexible substrate and between the flexible substrate and the ceramic substrate. .

[Problems to be Solved by the Invention] As described above, the conventional wire connection structure for a thermal head array has a configuration in which two bus bars are stacked and a flexible substrate is sandwiched between the bus bars. However, there is a problem that the press-fitting by the holding metal becomes insufficient, and a through hole for connecting the upper wiring pattern and the lower wiring pattern of the flexible substrate becomes complicated.

The present invention has been made in order to solve such a problem, and while making the shape of the thermal head compact,
It is an object of the present invention to provide a lead wire connection structure of a thermal head array that can reduce the electrical resistance of a power supply conductor and a ground conductor and improve the quality of recording.

[Means for Solving the Problems] A lead wire connecting structure for a thermal head array according to the present invention has a bus bar embedded in a heat sink.

[Operation] Since the heat radiating plate is made of a conductor such as aluminum, the bus bar and the heat radiating plate are insulated to embed the heat radiating plate in the heat radiating plate, and the bus bar is so pressed that the surface of the bus bar is sufficiently pressed against the flexible substrate. Elastic members are laid down or both up and down.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing an embodiment of the present invention, in which the same reference numerals as those in FIG.
(13) is a bus bar constituting a ground conductor, (16) is a flexible board on the power supply side, (17) is a flexible board on the ground side,
(23) is an insulator, and (24) is an elastic member.

As shown in FIG. 1, the bus bars (11), (12), (1)
3) is laid in the groove provided in the heat sink (19), so that an extra volume for the busbar is not required, and the flexible substrates (16) and (17) have only one surface on the busbar. (11), (12), (13) and ceramic substrate (1
8), so that the wiring pattern on the flexible substrate can be simplified.

FIG. 2 is a schematic sectional view showing another embodiment of the present invention, in which the same reference numerals as in FIG. 1 denote the same or corresponding parts, and two bus bars (11) and (12) An example in which insulation is provided in the same groove is shown. In any case, an elastic member (24) is provided below each of the busbars (11) and (12), and the busbars (11) and (12) are pushed up to improve the contact property.

Further, as shown in FIG. 2, each bus bar (1) is provided at a position corresponding to the bus bar (11) of the holding bracket (20).
The elastic members (24) may be provided individually or collectively in correspondence with (1) and (12). By doing so, the bus bars (11) and (12) and the flexible substrate 816) are pressed from above and below, and the contact is further improved.

[Effects of the Invention] As described above, the present invention has the effect of making the shape of the thermal head compact, reducing the electrical resistance of the power supply conductor and the grounding conductor, and improving the quality of recording.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of the present invention, and FIG.
FIG. 4 is a schematic sectional view showing another embodiment of the present invention, FIGS. 3 and 4 are connection diagrams showing the structure of a thermal head array, and FIG. 5 is a schematic sectional view showing a conventional structure. 1 ... thermal head array, 8-1, 8-2 ... reverse current blocking diode, 9-1, 9-2 ... power supply side wiring pattern, 11, 12, 13 ... bus bar, 16 ... power supply side Flexible board, 17 …… Ground side flexible board, 18 ……
Ceramic substrate, 19 ... heat sink, 23 ... insulator, 50 ...
Power conductor, 60 ... ground conductor. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A thermal head substrate having a plurality of thermal heads as a single heat-generating recording element and having a wiring pattern for supplying electric power or a signal to these thermal heads is installed on a heat radiating plate. In a conductor connection structure of a thermal head array in which necessary conductors are connected to a wiring pattern of a substrate,
A bus bar embedded so that the surface is exposed, a head-side conductor pattern overlapped with the wiring pattern of the thermal head substrate installed on the heat sink, and a bus bar-side conductor pattern overlapped with the bus bar embedded in the heat sink. A relay board on which a connection pattern for connecting these conductor patterns is formed; and press-contacting the relay board to a heat sink on which the thermal head board is installed, thereby connecting the head-side conductor pattern of the relay board to the wiring pattern of the thermal head board. Press-connecting means for connecting the bus bar-side conductor pattern of the relay board to the bus bars embedded in the heat sink, respectively.