KR900010048Y1 - Printer head driving circuit - Google Patents

Abstract

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Description

Printer head drive circuit

1 is a conventional print head drive circuit diagram.

2 is a printhead drive circuit diagram according to the present invention.

3 is a signal waveform diagram of respective parts of FIG.

* Explanation of symbols for main parts of the drawings

CPU: Central Processing Unit MV _1- MV ₄ : Monostable Multivibrator

I ₁ -I _n : Inverter R ₁ -R ₄ : Pulse width adjusting resistor

C ₁ -C ₄ : Pulse width condenser H ₁ -H _n : Head coil

Q _H -H _Hn : Head coil driving transistor

The present invention relates to a printing apparatus such as a printer, an electronic typewriter, and a facsimile, and more particularly, to a printer head driving circuit which can accurately control the operation of the head.

The conventional print head driving circuit is configured as shown in FIG. 1, and when the data processing in the printer is completed and the printing is to be performed, the instant when the output buffer stage (CPU) of the central processing unit (CPU) becomes low As the timer TM, the time for supplying power to the print head H is adjusted.

However, the conventional circuit does not check the output of the head drive pulse from the central processing unit (CPU) and then checks whether the output from the timer TM (actually the current flowing through the head coil) is abnormal. There is a problem in that the argument is not correct because it is an open loop method that can not be.

Therefore, in view of the above, the present invention precisely inspects the operation state of the head drive unit using a closed loop method, and if an abnormal condition occurs, the central processing unit checks it and provides abnormal status information to the outside of the system. It is an object of the present invention to provide a head driving circuit of a printer so that printing can be performed accurately.

The present invention for achieving this purpose is to supply power to the data buffer and the print head assembly to temporarily store and output the image data to be printed (Printing Image Data :) to be output from the central processing unit In a printer having a head power supply unit and a head coil drive unit for driving the printer head assembly in accordance with the operating state of the data buffer unit, the printer generates a pulse for adjusting the head drive timing by operating by a signal output from the central processing unit. It characterized in that it consists of a head drive pulse generator to check, and the inspection unit for confirming the normal presence of the generated head drive pulse.

Hereinafter, the technical configuration and the effect of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 shows the head drive circuit of the printer according to the present invention, as shown in the data buffer unit is respectively connected to the absorption pin data pod (P ₁ -P _2n -1) of the CPU (CPU) Connect to the number of inverters (I ₁ , I ₃ ...... I _2n -1) required for the number of odd head coils (H ₁ -H _2n - ₁ ) and the interrupt terminal (INT _A ) of the CPU Transistors Q ₁ -Q ₃ and a resistor network of a plurality of resistors. In addition, the data buffer section even-pin data port inverter (I ₂ -I _2n) as necessary are connected to each of an even number of coil heads (H ₂ -H _2n) to (P ₂ -P _2n) of a central processing unit (CPU), a central A transistor Q ₄ -Q ₆ connected to the interrupt terminal INT _B of the processing unit CPU and operating therein includes a resistor network of a plurality of resistors.

The head power supply unit includes transistors Q ₇ -Q ₉ for generating an output ₁ for supplying power to odd-numbered head coils H ₁ -H _{2 n} - ₁ , and even-numbered head coils H _2. Each of the transistors Q ₁₀ -Q ₁₂ generates an output Out ₂ for supplying power to -H _2n ).

The head coil driver operates in accordance with the operation state of the data buffer unit, thereby driving a plurality of transistors Q _H1 -Q _H2n - ₁ (Q _H2 -Q _H2n ) and a diode D ₁ for driving odd-numbered and even-numbered print head coils, respectively. -D _2n ).

Then, the head drive pulse generator is a monostable multivibrator MV ₁ (MV ₂ ) for generating odd and even head drive pulses, respectively, and a resistor R ₁ (R) for adjusting the pulse width of the corresponding pulse. ₂ ) and a capacitor (C ₁ ) (C ₂ ).

In addition, the inspection unit monostable multivibrator according to the present invention (MV ₃₎ monostable multivibrator for generating a pulse to monitor whether the respective outputs of (MV ₄₎ is normally output (MV ₃₎ (MV ₄₎ and the multi- A resistor (R ₃ ) (R ₄ ) and a condenser (C ₃ ) (C ₄ ) for adjusting the width of the pulses, which are the outputs of each of the vibrators, are configured as an acknowledgment terminal of the CPU. ACK ₁ , ACK ₂ ).

The operation of the second circuit constructed in this way will be described. Here, for convenience of description, only the method of driving the odd head pin will be described.

After image processing is completed inside the printer, the CPU sends a low-level interrupt signal (Fig. 3 (E)) through the interrupt terminal (INT ₄ ) to print the data in the printing buffer. It is human at the base of (Q ₁ ).

When a signal of low level to the base of the transistor (Q ₁₎ is a transistor (Q ₁₎ is turned on, the transistor (Q ₂₎ are also turned on, thereby turning on the transistor (Q _3). Accordingly, the collector of the transistor Q ₃ generates a high state signal as shown in FIG. 3 (F) and passes through the resistive network.

In addition, the CPU applies the printing image data such as FIG. 3G to the inverters I ₁ -I _2n - ₁ through the data ports P ₁ -P _2n - ₁ , respectively. These inverters invert the input data signal high and apply them to the bases of the plurality of transistors Q _H -Q _H2n - ₁ driving the printer head coils, respectively.

After the printing image data is output, the CPU outputs a signal as shown in FIG. 3A through the terminal OBF ₁ , and the OBF ₁ signal after the data is output becomes low. It is applied to the stable multivibrator MV ₁ .

At this time, the multivibrator MV ₁ is operated by the input signal (Fig. 3a), and its output is adjusted by the time constant determined by the resistor R ₁ and the condenser C ₁ and the It becomes like B).

3b the high output of monostable multivibrator (MV ₁₎ such help is applied to the base of the transistor (Q ₇₎ turns on the transistor (Q _7). When transistor Q ₇ is turned on, the base of transistor Q ₈ goes low, transistor Q ₈ is turned on and transistor Q ₉ is turned on so that the collector of transistor Q _{7 in} FIG. The output signal out ₁ like D) is generated and applied to the printer head coil H ₁ -H _2n - ₁ and then the transistors Q _H1 -Q _H2n - ₁ through the diode D ₁ -D _2n - ₁ . Is applied to the collector.

Accordingly, when the transistors Q _H1 -Q _H2n - ₁ are driven, current flows in the printer head coils H _1- H _2n - ₁ , and the corresponding pins are printed during the actual printing time (FIG. 3 (H)). Reference)

On the other hand, the output of the monostable multivibrator MV ₁ (Falling Edge of FIG. _3B ) causes the monostable multivibrator MV ₃ to output the same signal as that of FIG. 3C. The magnitude of the fox width of this signal is adjusted by the resistor R ₃ and the capacitor C ₂ and applied to the anode terminal ACK ₁ of the CPU.

The central processing unit (CPU) reads the output of the monostable multivibrator (MV ₃ ) to ensure that the head drive pulse (FIG. 3B) is correctly output.

Since the operation of the circuit for driving the even-numbered head pins is also the same as described above, detailed description thereof will be omitted.

As described above, the head driving circuit of the printer according to the present invention controls the timing of the current applied to the head, and checks the head driving stage to read the abnormal state information to the outside of the system by reading it from the central processing unit when an abnormality occurs. By providing a feature that can safely protect the head required for printing.

Claims (3)

The printer head assembly according to the operating state of the data buffer unit for temporarily storing and outputting the printing image data output from the central processing unit, the print head power supply unit for applying power to the print head assembly, and the operation state of the data buffer unit. A printer having a head drive unit for driving, comprising: a head drive pulse generator for generating a pulse for controlling a head drive timing by operating on a signal output from the central processing unit, and outputting from the head drive pulse generator; The head drive circuit of the printer, characterized in that composed of an inspection unit for checking the normal presence of the pulse. 2. The method of claim 1, wherein the head driving pulse generating unit comprises: first and second monostable multivibrator, each generate pulses for driving the second head (MV ₁₎ (MV ₂₎ with the pulse generated by the the multi-vibrator A printer head drive circuit comprising a resistor (R ₁ ) (R ₂ ) and a condenser (C ₁ ) (C ₂ ) for adjusting the pulse width of the _device . The monostable multivibrator MV ₃ (MV ₄ ) according to claim 1, wherein the inspection unit operates according to the output signals of the monostable multivibrator MV ₁ and MV ₂ to generate a predetermined signal. A printer head comprising: a resistor (R ₃ ) (R ₄ ) and a capacitor (C ₃ ) (C ₄ ) for adjusting the width of the predetermined signal and supplied to the nozzle terminal of the central processing unit. Driving circuit.