JPS61261071A - Thermal head - Google Patents

Abstract

PURPOSE:To reinforce conduction of a common electrode inexpensively and efficiently and obtain a thermal head with high performance, by providing a common electrode member to be connected to common electrode leads, separately from an insulating substrate, in a thermal head at an edge part. CONSTITUTION:An insulating sheet 12 for insulating a base 11 and the common electrode lead 4 from each other and a conductor 14 consisting of a metallic foil disposed between a ceramic substrate 1 and the base 11 are electrically connected to an FPC9 through pins 13. An electric current is passed from an external power source to each heating resistor 2 through a connector 10, the FPC9, the pins 13, the conductor 14 and the common electrode leads 4, whereby heat can be generated according to recording information, and arbitrary printing can be conducted on a recording paper moved while being pressed against the heating resistors 2. Since the conductor 14 is connected to the common electrode leads 4 to form a common electrode, there is no need for a conduction- reinforcing member, so that the electrical resistance of the common electrode can be set to be sufficiently low even in the case of using an inexpensive material, and high-quality printing can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head, particularly to an improvement in a structure for increasing the current capacity of a common electrode connected to a heating resistor on an insulating substrate.

[Conventional technology]

Fig. 3(a) is a plan view showing the main structure of the circuit pattern of a conventional thermal head, and Fig. 3(a) is a front view thereof.
Figure 4 is its equivalent circuit diagram, in which (1) is the ceramic substrate, (2) is the heating resistor, (3) is the control lead that controls the heating resistor, and (4) is the printing power supply (Gl). Common electrode leads to be connected, (6) is the common electrode, (6) is a conductive reinforcing material to reduce the electrical resistance of the lead (4) to the common electrode (6), (γ) is 0N10II' by the symbol signal
F switching element (hereinafter referred to as work C) % (
3) is a signal terminal, (9) is a 7 lexiple lead board (hereinafter referred to as FPC) that connects the circuit on the ceramic board (1) and the external circuit, and (to) is attached to this FPC (9). It is a connector that has been installed.

A conventional thermal head is constructed as described above, in which a pulse current is passed through dots formed by arranging a plurality of heating resistors (2) on an insulating substrate (1), and thermal paper is heated as the dots generate heat. Or, it prints by coloring or transposing a heat-sensitive ink sheet, and is used in the printing section of facsimiles or printers.

By the way, in this kind of thermal head.

In order to energize the heat generating resistor (2) and generate heat, a voltage is applied to the common electrode lead (4) of the heat generating resistor (2).
The control lead (3) will be connected to the power source (G) via the wire C (7), which is set to 0N10FF according to the recorded information. In this state, by supplying the recording information signal to the machine C (7), the required dots according to the signal generate heat,
Any desired printing can be performed on the recording paper that runs in pressure contact with these dots.

The current path used to generate heat during printing is explained in Figure 4 from the power supply (G) to the connector to the common electrode (5
) → After energizing each heating resistor (2) via the common electrode lead (4), return to the power supply (GJK) via the control lead (3) → Engineering C (7) → Signal terminal (3) → Connector.

When the current passes through such a path, for example, if all black is printed, that is, all the switches of C (7) are in the ON state, and all the heat generating resistors (2) are energized, the total current is A4 8 dots in size (216mg)/0.
044/216 (mm) x 8 (dot) x as a dot
o, 04 (Al = 69.12 (A), so
It is usually divided into four or eight parts. However, in the case of 4 divisions, 69.12 (Al/4 = 17.27 (
A) In the case of 8 divisions 69.12 (Al/8 = 8.63
(For the common electrode lead (4), which is made of aluminum and cannot have a conductor cross-sectional area due to its structure, the conductor resistance becomes a value that cannot be ignored in terms of printing quality. Therefore, conductive reinforcing material (6) as shown in Figure 3)
is overlaid on the circuit pattern of the common electrode lead (4) formed by a thin film method to ensure a conductor cross-sectional area.

[Problem that the invention seeks to solve]

In the conventional thermal head as described above, when trying to further downsize the thermal head, the common electrode lead (4
) It is necessary to make the pattern of the common electrode lead (4) much narrower, as in the past, conductive reinforcing material (
6), the thickness of the conductive reinforcing material (6) would become thicker, which would hinder the running of the printing paper or ink sheet, which necessitated the need for other methods. .

The present invention was made to solve these problems, and an object of the present invention is to obtain a high-performance thermal head by reinforcing the conductivity of the common electrode at low cost and efficiently.

[Means for solving problems]

In the thermal head according to the present invention, a common electrode member connected to a common electrode lead is provided separately from an insulating substrate on which a heating resistor and a common electrode are formed.

[Effect]

In this invention, the common electrode member connected to the common electrode lead is provided separately from the insulating substrate.
It is possible to easily secure a large conductor cross-sectional area that does not interfere with the running of the printing paper or ink sheet, and even with inexpensive materials, the electrical resistance of the common electrode can be made sufficiently small to obtain high-quality printing.

〔Example〕

1(a) and (1)l show one embodiment of the present invention, and in FIG. 1, the same reference numerals as in FIG. 6 and FIG.
or a corresponding portion. (10a) is the connector pin for connecting the external power supply and print signal, a3J is the base for attaching the ceramic board (1) and FPC (9), etc., (capital) is the base (9) and the common electrode lead. (4)
An insulating sheet is used to insulate between the pins, and σ is a conductor made of metal foil placed between the ceramic substrate (1) and the base CI. '
It is electrically connected to PC (9).

In the thermal head configured as above, an external power supply (not shown) is connected to the connector in order to generate heat in the heating resistor (2), and the current path by this external power supply is as follows. .

In other words, the connector shouts from the external power supply → F P C (9)
→ Bin α mark → Conductor Cl4) → Each heating resistor (2) is energized via the common electrode lead (4), and then the control lead (3) → Work C (γ) → Signal terminal (3) → F P C<9
')→The connector returns to the external power supply via O. In such a current path, C(γ) is 0N depending on the recorded information.
Since the heating resistor (2) has a switching function of 10FF, the heating resistor (2) can generate heat according to the recorded information. can be printed.

By the way, in this case, since the conductor α4 is connected to the common electrode lead (4) and used as a common electrode, the conventional conductive reinforcing material (6) is not required, which obstructs the running of the recording paper or ink sheet. There is no. Furthermore, since a sufficiently large conductor cross-sectional area can be easily secured, it is possible to sufficiently reduce the electrical resistance of the common electrode even with inexpensive materials.

In the above embodiment, a conductor made of metal foil is arranged between the ceramic substrate (1) and the base α that holds it to serve as a common electrode member.
The base (b) itself may be used as a common electrode member as shown in Figure 1), and similar effects can be expected.

〔Effect of the invention〕

As explained above, in this invention, since the common electrode member connected to the common electrode lead is provided separately from the insulating substrate, it is possible to easily create a large cross-sectional area without interfering with the running of printing paper or ink sheet. Furthermore, even with inexpensive materials, the electric resistance of the common electrode can be sufficiently reduced to obtain high quality printing.

[Brief explanation of the drawing]

FIG. 1 fa+ is a perspective view of a thermal head showing an embodiment of the present invention, FIG.
3(b) is a sectional view thereof, and FIG. 3(a) is a plan view showing the pattern configuration of a conventional thermal head; FIG.
is a similar front view, and FIG. 4 is its equivalent circuit diagram. (1): Ceramic substrate (2): Heat generating resistor (4):
Common electrode lead (2): Base CI@: Conductor In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] (1) In an edge-type thermal head in which a plurality of heating resistors and their common electrode leads are respectively formed on the upper surface of an insulating substrate, the common electrode member connected to the common electrode lead is not connected to the insulating substrate. A thermal head characterized by being provided separately. (2) The thermal head according to claim 1, wherein the common electrode member is formed of a metal foil placed between the insulating substrate and the base on which it is mounted. (3) The thermal head according to claim 1, wherein the common electrode member is a base on which an insulating substrate is mounted.