JPS589316Y2 - Malfunction prevention device in printing equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for preventing malfunction of a printing device.

A printing device, for example, a line printer, which is a mechanical printing device, generates a pulse synchronized with the rotation of a type drum, drives a magnet coil in synchronization with the pulse, and... attracts the printer to print the desired print. I do.

However, if the electric motor that drives the type drum stops or the fuse blows out, the homogeneous pulse becomes constantly at a high level.
Or, if the level becomes constantly low and becomes direct current, the printing operation will not be synchronized, and current will constantly flow through the magnet coil, causing damage to the transistor connected to the magnet coil, erroneous printing, or paper feed. , causing abnormalities such as ribbon shift.

□Also, in non-mechanical printing devices such as discharge printing devices and thermal printers, pulses are generated in synchronization with the movement of the print head, and the print head is energized in synchronization with the pulses to produce the desired print. Therefore, if the print head stops for some reason and an abnormality occurs in the synchronization pulse, electricity will continue to be printed at a specific position.

Therefore, there is a risk that the printed paper will break and a large current will flow through the broken part and burn out the electrodes.

The purpose of this invention is to detect abnormalities in the synchronization pulses to prevent damage to the printing device and erroneous printing.

Hereinafter, embodiments of the malfunction prevention device according to the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a type drum, and a disk 2 is attached to its rotating shaft.By detecting a detected object 2a provided on the disk 2 with a detector 3, the type drum 10 is
A pulse 11 synchronized with the rotation is transmitted.

Reference numeral 4 denotes a magnet coil for attracting a magnet (not shown), which is disposed opposite to the type drum, and is connected to the emitter of a transistor 6 in parallel with a diode 5 for absorbing back electromotive force.

The base of transistor 60 is connected to the collector of transistor 8 through resistor 7, and the base of transistor 80 is connected to the collector of transistor 10 through resistor 9.

A print signal (2) is supplied to the base of the transistor 100 in synchronization with the synchronization pulse (1).

The emitters of transistors 8 and 10 are grounded, and the collector of transistor 8 is connected to the power supply voltage -V through a resistor 11.

is supplied, and a resistor 1 is connected to the collector of the transistor 10.
An output terminal 32 of the circuit 21 is connected via 2.

As a result, the collector of transistor 6 has power supply voltage +vcc.
is supplied to the emitter via a magnet coil 4 and a diode 5 to a power supply voltage -V.

is supplied. In the circuit 21, its input terminal 2
2 is connected to the base of the transistor 250 via a resistor 23 and a capacitor 24.

The emitter of the transistor 25 is connected to the power supply voltage -vo, and the collector is grounded via a resistor 26.

Note that the resistor 27 connected between the base and emitter of the transistor 250 is a resistor for preventing reverse resistance of the transistor 25.

The collector of transistor 25 is connected to the base of transistor 29 via diode 28, and the base is grounded via resistor 30 and capacitor 31.

The emitter of the transistor 29 is connected to the output terminal 32 and grounded via a resistor 33, and the collector is connected to the power supply voltage -■.

is supplied. Next, the operation will be explained.

The synchronization pulse 11 emitted from the detector 3 is, for example, the second
Let's assume the normal waveform shown in Figure a.

When this synchronizing pulse ■1 enters the input terminal 22 of the circuit 21, the transistor 25 outputs the high level (0) of the synchronizing pulse ■1.
volts) and conducts at a low level (-V.

(volt), it becomes non-conductive. At this time, the transistor 250
The base potential changes as shown in FIG. 2, and the collector potential changes as shown in FIG. 2C.

When transistor 25 is conductive, capacitor 31 is charged and when transistor 25 is non-conductive, it is discharged through resistor 30.

At this time, assuming that the capacitance value of the capacitor 31 is R and the resistance value of the C1 resistor 30 is R, the capacitor 31 is discharged with a time constant CR.

The charging/discharging waveform of the capacitor 31 is transmitted to the base of the transistor 290, the emitter of the transistor 29, and appears at the output terminal 32.

Changes in the base potential and emitter potential of the transistor 290 at this time are shown in FIGS. 2d and 2e.

When the homogeneous pulse 11 is normally transmitted as shown in FIG. 2a, the output of the output terminal 32 of the circuit 21 is as shown in FIG. 2e.
Since the transistor 10 is held at a low level as shown in FIG.

Transistors 6 and 8 repeat conduction and non-conduction according to the square wave of , and transistors 6 and 8 are non-conductive when transistor 10 is conductive, and conductive when transistor 10 is non-conductive, so magnet coil 4 normally operates the hammer by print signal ■2. Drive to.

Furthermore, if an accident occurs such as the motor of the type drum 1 stopping or a fuse blowing out, and the synchronizing pulse 11 continues to maintain a high level or low level and becomes a direct current, the transistor 25 is turned off by the direct current blocking action of the capacitor 24. It is always non-conductive, and as a result, the transistor 29 is also non-conductive and the output terminal 32 of the circuit 21 is at a high level (0 volts).

When the output terminal 32 goes high, the transistor 6.8
．． 10 become non-conductive and the printing operation stops.

Note that the reason why the output of the circuit 21 is always maintained at a low level by providing a time constant with the resistor 30 and the capacitor 31 is that a circuit having the same configuration as the circuit shown in FIG. 1 is used for paper feeding. (In order to use the magnet coil 4 as a paper feeding coil, the current flowing through the transistor 6 must be DC.) Otherwise, the resistor 30 and capacitor 31 There is no particular need to provide it.

As described above, this invention has an extremely simple configuration and can prevent malfunctions of the printing device due to abnormalities in pulses synchronized with the movement of the printing section.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of the malfunction prevention device according to this invention, and FIG. 2 is a diagram showing signal waveforms in the main parts of the circuit of FIG. 1. Explanation of symbols, 1: Type drum, 2: Disk, 3: Detector,
4: Magnet coil, 6: Transistor, 10: Transistor, 21: Circuit, 22: Input terminal of circuit 21,
24: capacitor, 25: transistor, 27: resistor, 29: transistor, 32: output terminal of circuit 21, 3
3: Resistor, I1: Synchronous pulse, I2: Print signal.

Claims (1)

[Claims for Utility Model Registration] A printing device that executes a printing operation based on a printing signal output in synchronization with the movement of a printing section, the synchronized pulse generation generating a pulse in synchronization with the movement of the printing section. means, a printing operation execution means, a voltage output means for outputting a predetermined voltage that enables the printing operation execution means to execute a printing table operation, and an output based on a synchronization pulse generated by the synchronization pulse generation means. and printing control means for supplying the output voltage of the voltage output means to the printing operation execution means in response to a printing signal generated by the printer, and for causing the printing operation execution means to perform a predetermined printing operation, a switching transistor having an electrode connected to an off potential, receiving the output of the synchronizing pulse generating means via a capacitor to the control electrode, and turning on based on the generation of the synchronizing pulse; , outputting a predetermined voltage that enables the printing operation execution means to execute the printing operation, and outputting a predetermined voltage that disables the printing operation execution means in the printing operation execution means based on the turning off of the switching transistor. said voltage output means comprising output means, and when the output of said synchronized pulse generation means becomes direct current, the output voltage of said voltage output means disables execution of a printing operation in said printing operation execution means. What is claimed is: 1. A malfunction prevention device for a double-sided device, characterized in that malfunction is prevented by configuring a predetermined voltage.