JPH0811340A - Drive circuit and electronic part using the same - Google Patents

Abstract

PURPOSE:To provide interchangeability with respect to the control signal of the drive circuit of a conventional thermal head without requiring the transfer of signal data for preheating. CONSTITUTION:A drive circuit is equipped with a plurality of arranged elements 1 to be driven, a latch circuit 5 holding a serial signal data becoming the drive data of the elements 1 to be driven to output them in parallel, an OR circuit 12 outputting ON data for driving the elements 1 to be driven regardless of the drive data and the NAND circuit 3 connected to the elements 1 to be driven which are driven by the drive data from the latch circuit 5 or the ON data from the OR circuit 12 and the control signal terminal of the latch circuit 5 is connected to the control signal terminal of the OR circuit 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a thermal head of a thermal recording apparatus, and more particularly to a drive circuit for driving a heating element of the thermal head and an electronic component using the drive circuit.

[0002]

2. Description of the Related Art A thermal recording system using a thermal head has been widely used in recent years because of its simple structure. The thermal head in this thermal recording system selectively energizes and drives a large number of heating elements arranged on the substrate,
Printing is performed by coloring the portion of the recording paper that is in contact with the heating element that has generated heat, and various driving methods are known, and a typical one is shown in FIG. .

FIG. 12 shows a circuit diagram of a conventional thermal head disclosed in Japanese Patent Laid-Open No. 59-27564. In FIG. 12, reference numeral 1 denotes N heat generating elements constituting the thermal head. , It becomes a driven element. Reference numeral 2 is a drive circuit that supplies a drive signal to each of the N heating elements 1 to drive them.

In the drive circuit 2, 3 is a NAND circuit as a switching element provided corresponding to each of the N heat generating elements 1, and 4 is serial signal information as a drive signal for the heat generating element 1. A shift register 5 for shifting in synchronization with a clock signal, and 5 is a latch circuit as a holding means for holding the contents of the shift register 4 based on a predetermined latch signal.

Further, 6 is a data input terminal for serially inputting signal information (DATA signal) to the shift register 4,
Reference numeral 7 is a clock input terminal to which a clock signal (CLOCK signal) of the shift register 4 is input, 8 is a data output terminal from which signal information (DATA OUT signal) shifted in the shift register 4 is output, and 9 is a latch circuit 5 To the NAND circuit 3, 10 is a strobe input terminal to which a strobe signal (STROBE signal) is input, and 11 is a common electrode to which the heating elements 1 are commonly connected. is there. The power supply and ground terminals of the circuit are not shown.

Next, the operation will be described. Heating element 1
The DATA signal for driving the clock signal is serially input to the shift register 4 from the data input terminal 6 and the clock input terminal 7
Are sequentially shifted in the shift register 4 in synchronization with the CLOCK signal given to the. When the DATA signal for one line is input to the shift register 4, the LATCH signal is input to the latch input terminal 9 of the latch circuit 5, and as a result, the latch circuit 5 receives the LATCH signal based on the LATCH signal. Keep the content. In this case, the data in the shift register 4 is transferred to the latch circuit 5 as "Low" of the LATCH signal, and "Hi" as the continuation of the holding.
It is set to the logic "gh".

The shift register 4 and the latch circuit 5 are constructed as shown in FIG.
This is because the DATA signal is transferred during the driving of (1) to enable high-speed printing processing, and the content of the latch circuit 5 becomes the DATA signal of the heating element 1. In addition, a switching element (NAND circuit) 3 corresponding to each heating element 1
Is a STROBE input to the strobe input terminal 10.
The switching operation is performed based on the signal and the logical state of the drive signal held in the latch circuit 5. That is, the period in which the STROBE signal is “Low” is the drive time of the heating element 1.

FIG. 13 is a timing chart showing the operation of the thermal head shown in FIG. C in the figure
OMMON indicates a voltage input to the common electrode 11, and is, for example, 12V, 24V or the like. In the figure, DATA signal, CLOCK signal, LATCH signal,
The STROBE signal indicates the type of signal input to each of the above terminals.

The thermal head having such a structure records an image on the thermal paper by selectively energizing the heating element 1, and the energization time of the heating element 1 depends on the environmental temperature and the temperature of the thermal head itself. Image quality is improved by changing the image quality. Normally, control is performed such that the energization time is lengthened when the temperature is low and the energization time is shortened when the temperature is high. On the other hand, in the thermal recording apparatus, the heating element driving power source of the thermal head can increase the resistance value of the heating element 1 and reduce the driving power source capacity if the printing quality at low temperature can be ignored. This ambient temperature and the heating element drive time (STRO
The relationship of the BE pulse width) is shown in FIG. Therefore, in a portable battery-operated thermal recording device or the like, there are cases in which the print quality at low temperatures must be ignored. However, as a countermeasure, the thermal paper and the thermal head itself are preheated during printing standby so that the printing quality is satisfied even at low temperature.

An example of the timing of this control is shown in the timing chart of FIG. As shown in the figure, the heating element 1 is energized for a period of time including preheating based on signal information of all black data and data ON based on driving information. In this case, electromagnetic interference (Electromag)
netic interference, below, EMI
In consideration of the countermeasures, it is desired that the frequency of the clock signal is low, and the experimental results have revealed that the optimum transfer rate of the clock signal is 500 KHz or less.

FIG. 16 shows a circuit configuration in which the signal information for preheating is not transferred (see Japanese Patent Laid-Open No. 63-63115).
No. 218375) is known. In the case of this circuit configuration, NOR for turning on the drive information of the heating element 1
A circuit 20 is provided, and an input signal terminal 1 to the NOR circuit 20 is provided.
By inputting "High" to 3 (ALL ON signal), the drive information of the heating element 1 can be changed to ON regardless of the drive information of the latch circuit 5. In addition, the drive information includes data transfer holding to the latch circuit 5 and “Lo of the STROBE signal.
The timing when driving becomes possible with w "is shown in the timing chart of FIG.

In addition, as a reference technical document related to the present invention, there is a "driving circuit" disclosed in Japanese Patent Laid-Open No. 5-96769.

[0013]

However, as shown in FIG.
In the conventional example shown in (1), it is necessary to transfer the signal information for preheating at low temperature and the printing speed is determined according to the transfer speed of the clock signal, so that the processing speed cannot be improved. There was a problem.

Further, in the conventional example shown in FIG. 16, the number of signals for controlling the thermal head increases, and the hardware of the thermal recording apparatus itself needs to be changed, resulting in incompatibility with the conventional thermal head. There was a point.

The present invention has been made in view of the above, and does not require transfer of signal information for preheating,
A first object of the present invention is to obtain a drive circuit compatible with the control signal of the conventional thermal head drive circuit and an electronic component using the drive circuit.

A second object is to provide a driving circuit for a heating element suitable for a small-capacity power source such as a battery power source of a portable thermal recording device, and to obtain an electronic component using these circuits. .

[0017]

In order to achieve the above object, a drive circuit according to a first aspect of the present invention comprises a plurality of driven elements and a serial signal serving as drive information for each of the driven elements. Drive information holding means for holding information and outputting the signal information in parallel, and ON for outputting ON information for driving the driven element regardless of the drive information
A control signal for the drive information holding means, comprising: an information output means; and a switching element connected to the driven element driven by the drive information from the drive information holding means or the ON information from the ON information output means. The terminal and the control signal terminal of the ON information output means are connected.

The drive circuit according to a second aspect of the present invention holds a plurality of driven elements and serial signal information serving as drive information of each of the driven elements, and outputs the signal information in parallel. Drive information holding means, ON information output means for outputting ON information for driving the driven element regardless of the drive information, drive information from the drive information holding means or ON from the ON information output means A switching element connected to the driven element driven by information is provided, and a synchronization signal input terminal of the serial signal information and a control signal terminal of the ON information output means are connected.

The drive circuit according to a third aspect of the present invention is the O
A pull-down resistor or a pull-up resistor is connected to the control signal input terminal of the N information output means.

A drive circuit according to a fourth aspect of the present invention includes a switching drive means for performing a logical operation in which adjacent elements of the driven elements are inverted from each other.

According to another aspect of the present invention, there is provided an electronic component using a driving circuit, which includes a plurality of driven elements arranged by heating elements and serial signal information serving as driving information for each driven element. Drive information holding means for holding and outputting the signal information in parallel, ON for outputting ON information for driving the driven element regardless of the drive information
An information output means, a switching element connected to the driven element driven by the drive information from the drive information holding means or the ON information from the ON information output means,
The control signal terminal of the drive information holding means and the drive circuit to which the control signal terminal of the ON information output means are connected are integrated.

According to another aspect of the present invention, there is provided an electronic component using a driving circuit, comprising a plurality of driven elements arranged by heating elements, and serial signal information serving as driving information for each driven element. Drive information holding means for holding and outputting the signal information in parallel, ON for outputting ON information for driving the driven element regardless of the drive information
An information output means, a switching element connected to the driven element driven by the drive information from the drive information holding means or the ON information from the ON information output means,
The serial signal information synchronization signal input terminal and the ON
The drive circuit connected to the control signal terminal of the information output means is integrated.

[0023]

In the drive circuit according to the present invention (claim 1), when the control signal of the drive information holding means is "High", the data is held, when the control signal is "Low", the data of the shift register is held and transferred to the holding circuit. And the logic "L
At the time of "ow", by transferring ON information to the switching drive circuit as a control signal operation of the ON information output means, the drive information holding control and the ON information output means can be controlled by one signal input terminal. It is possible to eliminate the need for preheat data transfer while maintaining compatibility with the same signal.

Further, in the drive circuit according to the present invention (claim 2), when the control of the ON information output means is the "High" level of the CLOCK signal which becomes the synchronization signal of the serial signal information, the O circuit is turned on.
By setting to N, one signal input terminal can control the synchronization signal input and the ON information output means, and the same signal as the conventional drive circuit can be used, but the data transfer for preheat is not required while having compatibility. Can be

Further, in the drive circuit according to the present invention (claim 3), the pull-down resistor or pull-up resistor of the ON information control signal terminal, for example, the ON information control signal, is an input signal due to a cable disconnection or the like. If there is not, for example, the circuit is fixed so that it does not become ON information, and a safety measure is realized.

Further, in the drive circuit according to the present invention (claim 4), the switching drive for performing the logical operation in which the adjacent elements are inverted with respect to each other is to eliminate the power loss as much as possible when the driven elements are driven in one division. It is possible to perform such two-division chopping drive, and it is possible to eliminate the need for preheat data transfer while maintaining compatibility with the same signal as the conventional drive circuit.

An electronic component using the drive circuit according to the present invention (claim 5) has a structure in which the heating element and the drive circuit described in the above claim are integrated, and the signal of the conventional electronic component While having compatibility, data transfer for preheat can be eliminated.

An electronic component using the drive circuit according to the present invention (claim 6) has a structure in which the heating element and the drive circuit described in the above claim are integrated, and the signal of the conventional electronic component While having compatibility, data transfer for preheat can be eliminated.

[0029]

【Example】

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a drive circuit according to the first embodiment. In the figure, reference numeral 1 denotes N heat generating elements of a thermal head, which are driven elements. Reference numeral 2 is a drive circuit that supplies a drive signal to drive each of the N heating elements 1.

In the drive circuit 2, 3 is N
A NAND circuit as a switching element provided corresponding to each of the heating elements 1, 4 is a shift register for synchronizing the serial information signal serving as the driving signal of the heating element 1 with the clock signal and shifting the inside thereof. , 5 are latch circuits as holding means for holding the contents in the shift register 4 based on a predetermined latch signal.

Further, 6 is a data input terminal for serially inputting an information signal (DATA signal) to the shift register 4,
Reference numeral 7 is a clock input terminal to which a clock signal (CLOCK signal) of the shift register 4 is input, 8 is a data output terminal from which an information signal (DATA OUT signal) shifted in the shift register 4 is output, and 10 is a NAND circuit 3 A strobe input terminal to which a strobe signal (STROBE signal) is input, 11 is a common electrode to which the heating elements 1 are commonly connected.

Further, 12 is an ON information output means composed of an OR circuit for outputting ON information for driving the heating element 1 regardless of the drive signal, and 14 is a control signal (LATON signal) for the latch circuit 5. It is a latch input terminal and also a control signal input terminal of the ON information output means (OR circuit) 12. Reference numeral 15 is an inversion output circuit of the LATON signal, and an output from the inversion output circuit 15 becomes an input signal of the OR circuit 12.

Next, the operation will be described. When the LATON signal from the latch input terminal 14 is “High”,
The latch circuit 5 holds the data, and conversely, in the case of "Low", the operation of transferring the data of the shift register 4 to the latch circuit 5 is the same as the conventional example. By the way, when the LATON signal from the latch input terminal 14 is “Low”, the OR circuit 1 which becomes ON information by the inverting output circuit 15
The input signal to 2 becomes "High", and as a result,
The output signal from the OR circuit 12 is O regardless of the drive information.
It becomes N information. From this, the conventional example, the input signal terminal 13 (ALL ON) shown in FIG.
It is possible to realize a circuit configuration that can be shared with.

Therefore, as shown in the timing chart of FIG. 2, when the LATON signal is "Low", ST
If the ROBE signal is "Low", preheating is possible. When the LATON signal is "High", STROB
If the E signal is "Low", the heating element 1 is driven based on the drive data, the number of signals is the same as the number of signals of the conventional drive circuit, and moreover, by changing the logic of the LATCH signal by software, Compatibility in hardware can be obtained.

[Second Embodiment] Next, a second embodiment will be described. In the first embodiment, the LATON signal
Although it served as both the control signal for the latch circuit 5 and the control signal for the ON information output means 12, as shown in FIG. 3, it serves as both the clock signal and the control signal for the ON information output means 12, and the clock signal input terminal (CLKON signal). ), And even with such a configuration, the same effect as that of the first embodiment can be obtained. This timing is shown in the timing chart of FIG. In this case, the data is turned on when the CLKON signal is "High", and the preheat is performed when the STROBE signal is "Low".

[Third Embodiment] Next, a third embodiment will be described. FIGS. 5 and 6 show the circuit shown in FIGS. 1 and 3 in which a pull-up resistor 17 and a pull-down resistor 18 are connected to the latch input terminal 14 (LATON) and the clock signal input terminal 16 (CLKON), respectively. When the LATON signal and the CLKON signal cables, which are the connection cables for the thermal heads respectively, do not have the LATON signal input to the latch input terminal 14 and the clock signal input terminal 16 do not have the CLKON signal input due to, for example, disconnection. The input signal of the OR circuit 12 to "Lo
By performing the switching operation based on the drive information as w ″, the occurrence of erroneous printing on the heating element 1 can be eliminated and the reliability can be further improved.

Naturally, by connecting the pull-up resistor 17 to the strobe input terminal 10, the STROBE
The reliability when no signal is input can also be improved. Regarding the circuit and signal logic,
It can be changed arbitrarily.

[Fourth Embodiment] Next, a fourth embodiment will be described. FIG. 7 shows a modification of the circuit shown in FIG. 5, and a portion different from that shown in FIG. 5 is provided with a signal terminal 19 for a CHOP signal so that adjacent elements perform logical operations in which they are mutually inverted. That is. The timing of each signal at this time is shown in FIG. This is because when preheating is performed by the 1-division drive, the 2-division chopping drive is used to reduce the loss voltage due to the resistance of the internal common electrode, the ground resistance, etc. and make the power supply capacity effective when used as an electronic component. 2 shows a driving circuit for performing the above.

[Fifth Embodiment] Next, a fifth embodiment will be described. FIG. 8 shows a modification of the circuit shown in FIG.
The OP signal is generated inside the oscillation circuit 20. In this case, the same signal as that of the conventional drive circuit is compatible, but the preheat data transfer is not necessary and the two-division chopping drive can be performed. The timing chart at this time does not include the CHOP signal shown in FIG.

FIG. 10 shows the relationship between the loss voltage and the current. As the current increases, the loss voltage naturally increases. Even if the resistance value of the heating element, which is the driven element such as the thermal head, is 1 KΩ, there are multiple resistance values, so the total current will be large. In that case, division printing by dividing the STROBE signal will be performed, but chopping is performed. By incorporating it in a drive circuit that generates a CHOP signal for driving, divisional driving can be realized without changing the hardware on the thermal recording apparatus side.

[Sixth Embodiment] Next, a sixth embodiment will be described. FIG. 11 shows a schematic configuration of an electronic component in which the driven element is a heating element and the driving circuit is integrated into an IC chip. FIG. 11 shows an electronic component such as a so-called thermal head. In the figure, 21 is an insulating substrate, 22 is an electrode, and 2
Reference numeral 3 is a strip-shaped resistor disposed so as to straddle the electrodes, and 24 is one heating element. Further, 25 is a chip (hereinafter referred to as an IC chip) in which the driving circuit shown in the above-mentioned first to fifth embodiments is integrated, and 26 is arbitrarily connected to the IC chip 25 and the electrodes 22 and pins of a connector 27 which is an external connecting portion. For example, wires 28 are, for example, a printed wiring board, 29 is an insulating substrate 21, a support for the printed wiring board 28, and the like.

As described above, by connecting the individual heating elements 24 to the IC chip 25 and drawing the control input signal to the connector 27, the change of the drive circuit is compatible with the conventional electronic parts by the change of the IC chip 25. The connector 27 enables the characteristics.

[0043]

As described above, according to the drive circuit of the first aspect, the control signal terminal of the drive information holding means,
Since the control signal terminal of the ON information output means is connected, transfer of signal information for preheating can be eliminated,
In addition, it can be made compatible with the control signal of the conventional thermal head drive circuit.

According to the drive circuit of the second aspect,
Since the configuration is such that the synchronization signal input terminal for the serial signal and the control signal terminal of the ON information output means are connected, it is not necessary to transfer the signal information for preheating.
In addition, it can be made compatible with the control signal of the conventional thermal head drive circuit.

According to the drive circuit of the third aspect,
If the pull-down resistance or pull-up resistance of the control signal terminal for ON information is, for example, the control signal for ON information and there is no input signal due to a cable break, etc.
Since the circuit is fixed so that it does not become information, safety measures are realized.

According to the drive circuit of the fourth aspect,
Since the adjacent driven elements are configured to perform switching operation in which logical operations are inverted from each other, it is possible to perform two-division driving that minimizes power loss and is compatible with the control signals of the conventional thermal head drive circuit. It is possible to impart the property, and it is possible to eliminate the need to transfer the signal information for preheating.

Further, according to the electronic component using the drive circuit of the fifth aspect, since the heating element and the drive means are integrated, the above effects can be obtained, and the control signal of the drive circuit of the conventional thermal head can be obtained. Can be compatible with.

According to the electronic component using the drive circuit of the sixth aspect, since the heating element and the drive means are integrated, the above-mentioned effects are obtained and the control signal of the drive circuit of the conventional thermal head is obtained. Can be compatible with.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a drive circuit according to a first embodiment.

FIG. 2 is a timing chart showing the operation of the drive circuit shown in FIG.

FIG. 3 is a circuit diagram showing a configuration of a drive circuit according to a second embodiment.

FIG. 4 is a timing chart showing an operation of the drive circuit shown in FIG.

FIG. 5 is a circuit diagram showing a configuration of a drive circuit according to a third embodiment.

FIG. 6 is a circuit diagram showing a configuration of a drive circuit according to a third embodiment.

FIG. 7 is a circuit diagram showing a configuration of a drive circuit according to a fourth embodiment.

FIG. 8 is a circuit diagram showing a configuration of a drive circuit according to a fifth embodiment.

9 is a timing chart showing the operation of the drive circuit shown in FIG.

FIG. 10 is a graph showing the relationship between wiring resistance and loss voltage.

FIG. 11 is a perspective view showing a configuration of an electronic component according to a sixth embodiment.

FIG. 12 is a circuit diagram showing a configuration of a conventional drive circuit.

FIG. 13 is a circuit diagram showing a configuration of a conventional drive circuit.

14 is a timing chart showing the operation of the drive circuit shown in FIG.

FIG. 15 is a graph showing the relationship between the environmental temperature and the heating element drive time.

16 is a timing chart showing the timing in the case of performing preheating of the drive circuit shown in FIG.

17 is a timing chart showing the timing when preheating the drive circuit shown in FIG. 11.

[Explanation of symbols]

1 driven element, 2 driving circuit, 3 switching element, 4 shift register, 5 latch circuit, 6 data input terminal, 7 clock input terminal, 12 ON information output means, 14 latch input terminal, 16 clock signal input terminal, 17 pull Up resistance, 18 pull down resistance,
20 oscillator circuits

Claims (6)

[Claims] 1. A plurality of driven elements, drive information holding means for holding serial signal information which is drive information for each of the driven elements, and outputting the signal information in parallel, and the drive information. Irrespective of the above, ON information output means for outputting ON information for driving the driven element, and the driven information driven by the drive information from the drive information holding means or the ON information from the ON information output means. A drive circuit comprising: a switching element connected to the element, wherein a control signal terminal of the drive information holding means and a control signal terminal of the ON information output means are connected. 2. A plurality of driven elements, drive information holding means for holding serial signal information which is drive information of each of the driven elements, and outputting the signal information in parallel, and the drive information. Irrespective of the above, ON information output means for outputting ON information for driving the driven element, and the driven information driven by the drive information from the drive information holding means or the ON information from the ON information output means. A drive circuit comprising: a switching element connected to the element, wherein a synchronization signal input terminal for the serial signal information and a control signal terminal of the ON information output means are connected. 3. The drive circuit according to claim 1, wherein a pull-down resistor or a pull-up resistor is connected to the control signal input terminal of the ON information output means. 4. The drive circuit according to claim 1, further comprising switching drive means for performing a logical operation in which adjacent ones of the driven elements are inverted from each other. 5. A drive information holding device for holding a plurality of driven elements arranged by heating elements and serial signal information as driving information of each of the driven elements and outputting the signal information in parallel. Means for outputting ON information for driving the driven element regardless of the driving information
N information output means, a switching element connected to the driven element driven by the drive information from the drive information holding means or ON information from the ON information output means, and a control signal for the drive information holding means An electronic component using a drive circuit, characterized in that the drive circuit to which the terminal and the control signal terminal of the ON information output means are connected is integrated. 6. A drive information holding device for holding a plurality of driven elements formed of heating elements and serial signal information serving as drive information for each of the driven elements, and outputting the signal information in parallel. Means for outputting ON information for driving the driven element regardless of the driving information
N information output means, a switching element connected to the driven element driven by the drive information from the drive information holding means or ON information from the ON information output means, and a synchronization signal of the serial signal information. An electronic component using a drive circuit, characterized in that a drive circuit to which an input terminal and a control signal terminal of the ON information output means are connected is integrated.