JPH0890816A - Thermal head - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a thermal head capable of easily changing the input form of a print signal. [Structure] On an insulating substrate 2, a large number of heat generating resistors 3 and a plurality of drive ICs 6 which incorporates a shift register in which a print signal is stored and which selectively heats the heat generating resistors 3 by Joule heat. A thermal head 1 having a plurality of signal input lines 7 for inputting a print signal to a shift register of the driving IC 6 and a signal transfer line 8 for transferring a print signal between adjacent driving ICs 6 attached. , The signal input line 7
And the switching elements 9a-9 on each of the signal transfer lines 8.
c, 10a to 10c are connected in series.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a thermal head incorporated as a printer mechanism such as a word processor and a facsimile.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3A, a thermal head incorporated as a printer mechanism of a word processor or the like has a large number of heat generations made of tantalum nitride or the like on an insulating substrate 11 made of alumina ceramics or the like. A plurality of resistors 12, a common electrode 13 and an individual electrode 14 connected to each heating resistor 12, and a shift register connected to the individual electrode 14 and having the same number of bits as the heating resistors 12 inside. Driving IC15 (IC1-
8), a signal input line 16 for inputting a print signal from the outside to the shift register in the driving IC 15, and a signal transfer line 18 for transferring the printing signal between the adjacent driving ICs 15. It has a structure.

In addition to the shift register described above, a latch for holding the print signal of the shift register for a predetermined period inside the driving IC 15 and a heating resistor based on the print signal held by the latch. Latch signal line (not shown), which has a built-in drive element for controlling energization to 12 and receives a latch signal from the outside, is input to the latch.
However, strobe signal lines (not shown) to which strobe signals from the outside are input are connected to the drive elements, respectively.

At both ends of the shift register built in each driving IC 15, an input terminal SI for inputting a printing signal and a driving IC 15 to which the printing signal is adjacent are provided.
Output terminals SO for transfer to the shift registers of the respective shift registers, and by connecting the input terminals SI and the output terminals SO between the adjacent driving ICs 15, all the shift registers are connected in series. There is.

Next, the printing operation of the above-mentioned conventional thermal head will be described.

First, the print signal for one line is serially input and transferred bit by bit through the signal input line 16 and the signal transfer line 18 in synchronization with the clock signal, and the print signal for one line is stored in the shift register. To do.

Next, a latch signal is input to the driving IC 15 via the above-mentioned latch signal line, and the print signal in the shift register is held by the latch.

Next, a strobe signal is input to the driving IC 15 through the above-mentioned strobe signal line, and while the strobe signal is being output, on / off of the driving element is controlled based on the print signal in the latch. .

As a result, the heating resistor 12 is selectively caused to generate Joule heat, and the generated heat is conducted to a thermal paper or the like for thermal recording.

However, in this conventional thermal head, since there is only one signal input line 16 for inputting a print signal from the outside, it is necessary to store a print signal for one line in all shift registers. It is necessary to serially input the print signal for one line bit by bit in synchronization with the clock signal, and when performing high-speed printing, there is a problem that the print speed is restricted by the transfer time of the print signal. . Therefore, as shown in FIG.
By increasing the number of the print signal input lines 16 to, for example, 4 and simultaneously inputting print signals from the outside via these four signal input lines 16, the time required to input the print signals is reduced to a quarter. It can be shortened.

However, in order to manufacture a thermal head capable of simultaneously inputting print signals from the outside via the plurality of signal input lines 16 as described above, the print signal input lines 16 are required.
A new screen, photomask, or the like corresponding to the number of sheets is required, which requires a lot of time, labor, and manufacturing cost, which is troublesome and inconvenient.

[0012]

SUMMARY OF THE INVENTION The present invention has been conceived in view of the above problems, and an object thereof is to provide a thermal head capable of easily changing the input form of a print signal.

[0013]

A thermal head according to the present invention has a large number of heating resistors and a shift register in which a print signal is stored inside, which is built in on an insulating substrate. A plurality of driving ICs that generate Joule heat;
A thermal head comprising a plurality of signal input lines for inputting a print signal to a shift register of the driving IC and a signal transfer line for transferring the print signal to an adjacent driving IC, the thermal head comprising: A switching element is connected to each of the line and the signal transfer line.

[0014]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of a thermal head of the present invention. 1 is a thermal head, 2 is an insulating substrate, 3 is a heating resistor, 4 is an individual lead wire, 5 is a common lead wire. , 6 are driving ICs, 7 is a signal input line, 8 is a signal transfer line, and 9a to 9c and 10a to 10c are switching elements.

The insulating substrate 2 is made of an electrically insulating and good heat conductive material such as alumina ceramics,
The upper surface thereof serves to support the heating resistor 3, the driving IC 6 and the like.

On the upper surface of the insulating substrate 2, a large number of heating resistors 3 corresponding to pixels for one scan are arranged.

Since the heating resistor 3 is made of an electric resistance material such as tantalum nitride, it is necessary to cause the thermal paper or the like to develop color when electric power is applied through the individual lead wire 4 and the common lead wire 5. Fever to a certain temperature.

The heating resistor 3 has individual lead wires 4 individually connected to one end thereof and a common lead wire 5 commonly connected to the other end thereof.

The individual lead wire 4 and the common lead wire 5
Is made of a metal material such as aluminum and serves to apply a predetermined electric power to the heating resistor 3 based on a print signal.

The individual lead wires 4 are, for example, 64
The driving ICs 6 are individually connected to the driving ICs 6 (IC1 to 8) through a brazing material such as solder, and the driving ICs 6 have a function of selectively causing the heating resistor 3 to generate Joule heat based on a print signal.

The driving IC 6 has a shift register in which a print signal is stored, a latch for holding the print signal of the shift register for a predetermined period, and a heating resistor 3 based on the print signal held by the latch. Latch signal line (not shown) that has a built-in drive element that controls the energization to the
However, strobe signal lines (not shown) to which strobe signals from the outside are input are connected to the drive elements, respectively. Further, an input terminal SI for inputting a print signal and an output terminal SO for transferring the print signal to the shift register of the adjacent drive IC 6 are provided at both ends of the shift register built in each drive IC 6. Are provided respectively.

Further, on the upper surface of the insulating substrate 2, four signal input lines 7 for inputting a print signal to the shift register of the drive IC 6 and the transfer of the print signal between the adjacent drive ICs 6 are provided. Of the switching elements 9a to 9c for interrupting the input or transfer of the print signal, and the signal input line 7 and the signal transfer line 8 are attached to the signal transfer line 8 of FIG.
10a-10c are connected in series.

The switching elements 9a-9c, 10a
10 to 10c are electrically openable and closable relays and the like. For example, the switching element 9a is provided on the signal transfer line 8 connecting the IC 2 and the IC 3 as shown in FIG. Is connected to the output terminal SO side of IC2, and the other terminal is the input terminal SI of IC3.
Connected to the side.

This switching element applies the principle of an electromagnet, and when a current flows through the coil L, a magnetic field is generated in the axial direction of the winding of the coil L. Due to this magnetic field, the connecting piece S is displaced in a direction approaching the terminal and in a direction separating from the terminal, the connecting piece S is made of a conductive magnetic material, and the connecting piece S is displaced and pressed between the terminals. As a result, the terminals are electrically connected to each other.
When the connecting piece S is separated from the terminal,
The connection with the terminal is cut off.

In this way, the electric current of the signal transfer line 8 between terminals, that is, between IC2 and IC3, is controlled by the direction of the current flowing through the coil L or the conduction and interruption of the current flowing through the coil L. Can control the physical connection.

Next, the printing operation of the thermal head 1 of this embodiment will be described.

When the print signal is input from one place of the IC 1 (1 input), the switching elements 9a to 9c are closed,
The switching elements 10a to 10c are set to open.

In this state, first, the print signal for one line is serially input and transferred bit by bit through the signal input line 7 connected to the input terminal SI of the IC1 in synchronization with the clock signal, and the shift register The print signal for one line is stored in.

Next, the latch signal is input to the driving IC 6 through the above-mentioned latch signal line, and the print signal in the shift register is held by the latch.

Next, a strobe signal is input to the driving IC 6 through the above-mentioned strobe signal line, and while the strobe signal is being output, on / off of the driving element is controlled based on the print signal in the latch. .

As a result, the heating resistor 3 selectively generates heat, and one scanning line is printed on the thermal paper or thermal transfer film pressed by the thermal head 1. A series of images are printed by repeating the above-described operation while step-transporting the thermal paper or the thermal transfer film.

On the other hand, the print signals are sent to IC1, IC3, I
When inputting from 4 points of C5 and IC7 (4 inputs),
The switching elements 9a to 9c are set to open and the switching elements 10a to 10c are set to close.

In this state, a print signal for one line divided into four groups is connected to the input terminal SI of each driving IC6 of IC1, IC3, IC5, and IC7 in synchronization with the clock signal. One bit each is serially input and transferred via the signal input line 7, and a print signal for one line is stored in the shift register.

Next, after a latch signal is input to the driving IC 6, thermal recording is performed in the same cycle as in the case of 1 input described above.

In this way, the switching elements 9a-9c,
By controlling ON / OFF of 10a to 10c according to the input form of the print signal, it is possible to easily correspond to any input form. As a result, even if it is desired to change the input form of the print signal, there is no need to prepare a screen, a photomask, or the like according to the number of signal input lines 7.

The present invention is not limited to the above embodiments, and various modifications and improvements can be made without departing from the gist of the present invention. For example, in the above embodiments, a relay is used as a switching element. Was used,
Instead of this, a transistor or the like may be used as the switching element, and in this case also, the same effect as that of the above-described embodiment can be obtained.

Further, in the above embodiment, the relay is used as the switching element and the relay is mounted on the insulating substrate. Instead, however, the solder land divided at the center is used as the switching element. At the same time, the solder bumps may be provided on the flexible substrate connected between the insulating substrate and the external electric circuit, and in this case, the same effect as that of the above-described embodiment can be obtained.

[0039]

According to the thermal head of the present invention, since the switching element is connected to each of the signal input line and the signal transfer line, ON / OFF of the switching element can be easily controlled according to the input form of the print signal. Even if the input form of the print signal is changed, it is not necessary to provide a screen, a photomask or the like according to the number of print signal input lines.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a thermal head of the present invention.

FIG. 2 is a circuit diagram showing an electrical configuration of a switching element.

3A and 3B are configuration diagrams of a conventional thermal head.

[Explanation of symbols]

 1 ... Thermal head 2 ... Insulating substrate 3 ... Heating resistor 4 ... Individual lead wire 5 ... Common lead wire 6 ... Driving IC 7 ... Signal input wire 8 ... .Signal transfer lines 9a to 9c, 10a to 10c ... Switching elements

Claims (1)

[Claims] 1. A plurality of driving ICs having a large number of heating resistors and a shift register in which a print signal is stored inside, on an insulating substrate to selectively heat the heating resistors by Joule heat. A thermal head comprising a plurality of signal input lines for inputting a print signal to a shift register of a drive IC and a signal transfer line for transferring a print signal to an adjacent drive IC. And a switching element connected to each of the signal transfer lines.