JPH0647932A - Electronic equipment - Google Patents

Abstract

PURPOSE:To simplify a device in construction by providing a power source supplying an electric power to loads through a capacitor, motor-operated fans for cooling the loads, and means for discharging charges of the capacitor at the interruption of the power source by converting the charges to the torque of the motor-operated fans. CONSTITUTION:A power source 56 supplies a power source voltage 40V to drive circuits 52, 54 for a print head 22 and a coil 30 of a drive motor, 24V to drive circuit 72, 76 for motor-operated fans 70, 74 for cooling the print head 22, the coil 30 of the drive motor, and the power source 56, and 5V to a printing control part 50. A capacitor 62 is connected to a 40V output terminal of the power source 56 and the drive circuits 52, 54 and also connected to voltage conversion circuits 80, 82, 84 which are respectively connected to the motor-operated fans 70, 74 and the printing control part 50. When an input to the power source 56 is interrupted, charges accumulated in the capacitor 62 are converted to a voltage through the voltage conversion circuits 80, 82, 84 to be respectively supplied to the motor-operated fans 70, 74 and the printing control part 50. Thus, the print head 22 and the drive motor coil 30 are cooled, and 'power source OFF' is indicated on an operator panel until all the charges are discharged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device having a power supply for supplying electric power to a load via a capacitor. As such an electronic device, there is an impact type printer having a drive circuit for driving a printing coil.

[0002]

2. Description of the Related Art Impact printers include a type printer that prints by printing a character using a printing hammer, and a wire dot printer that prints on recording paper by driving printing pins (wire pins). In such an impact printer, a driving circuit connected to a common power source drives a printing hammer and a wire pin.

Normally, the normal print rate (such as shipping slip printing and program test printing) in the impact type dot line printer is about 10% on average. It is rare that all the pins of the print wire pin operate at the same time, and the state of multi-pin printing rarely continues for a long time, but depending on the print data, it may reach up to about 50% to 100% instantaneously.

Usually, the current required to drive one of the print wire pins is about several amperes, and if all pins are to be driven with this current, it will be about several tens of amperes. Therefore,
The power supply used for the printer requires a power supply with a rated capacity of about several tens of amperes. However, such a large-capacity power source requires a large space, the circuit configuration is complicated, and it is disadvantageous for downsizing the device.

Therefore, normally, printing can be performed by driving only about 10% of the printing wire pins, and therefore a small capacity power source is used. A large-capacity capacitor is provided between the power supply and the load in order to cope with an instantaneous load increase when using such a small-capacity power supply.

[0006]

However, when a large-capacity capacitor is used for the power supply output, when the power supply of the device is cut off and there is no load, the electric charge remains in the large-capacity capacitor. Become. In this state,
There is a risk of electric shock when performing maintenance work. There is also a problem that if the terminal comes into contact with another circuit, the circuit is destroyed.

For this reason, there is a method in which a resistor is connected in parallel with the large-capacity capacitor to convert this charge into heat and discharge it. However, this resistor has a problem that a large size is required and the temperature becomes high, so that a large space is required for mounting. The purpose of the present invention is to
An object of the present invention is to provide an electronic device capable of easily discharging the electric charge accumulated in the capacitor connected to the power output.

[0008]

An electronic device according to the present invention comprises a load 52, a power supply 56 for supplying electric power to the load 52 via a capacitor 62, an electric fan 70 for cooling the load 52, Means 80 for converting the electric charge of the capacitor 62 into the rotational driving force of the electric fan 70 to discharge the electric power when the power source of the apparatus is cut off.

[0009]

According to the electronic device of the present invention, the electric charge accumulated in the capacitor connected to the output of the power source is discharged through the electric fan, so that the structure is extremely simple and the load is cooled at the same time. Can be made.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is an explanatory diagram of the structure of an impact printer to which the present invention is applied. In the figure, the continuous folding sheet 2 has a tractor pin 4a that engages with its feed hole 2a.
It is transported by the tractor 4 having the. The paper feed motor 6 rotates the tractor 4 via the pulley 8, the belt 10 and the pulley 12 to convey the paper 2. The paper feed motor 6 is drive-controlled by the paper feed control unit 42 via the drive circuit 40. Paper feed control unit 4
2 executes a line feed operation of the paper 2 in response to a drive instruction from the print control unit 50.

The platen 14 is arranged so as to face the print head 22, and is driven to rotate through a pulley 16, a belt 18 and a pulley 20 to guide the paper 2. The print head 22 is composed of a plurality of print blocks (12) each mounting a plurality of print pins (24), and is mounted on a shuttle 26 that reciprocates along a guide rod 24. Therefore, the shuttle 2 has a total of 288 printing pins.
It is mounted on the 6.

The printing blocks 22a are mounted on the shuttle 26 by fastening means such as screws (not shown) that can be attached / removed, and can be replaced individually. In addition, the print blocks 22a to 22h have 24
Each of the wire pins of the book is attached so as to be arranged at a predetermined pitch in the vertical direction (the line feed direction of the paper 2). Then, each print wire pin of the print head 22 is driven in response to a drive instruction from the print control unit 50 via the drive circuit 52 which receives power supply from the power supply 56. Drive circuit 52
Includes 288 driving transistors for driving 288 electromagnetic coils provided corresponding to the respective print wire pins. The print wire pins are operated via the electromagnetic coils by individually supplying drive signals to the 288 drive transistors.

Incidentally, in FIG. 2, eight printing blocks (22a
22h). Further, the print head 22
Each of the print blocks 22a to 22h includes a print block 2
Thermistors (similarly, eight in FIG. 2) which are temperature detecting elements for detecting the heat generation temperatures of 2a to 22h 28
a to 28h are attached. Thermistors 28a-2
The detection output of 8h is input to the print control unit 50.

The shuttle 26 is reciprocally driven by a drive motor composed of a plurality of magnets 28 mounted on the lower surface of the shuttle 26 and a plurality of coils 30 mounted on the frame side of the impact printer. Drive motor coil 30
Is controlled by the print control unit 50 via the drive circuit 54, and the reverse drive operation, constant speed operation, stop operation, etc. of the shuttle 26 are controlled.

The print control unit 50 described above performs a line feed operation of the paper 2 and the shuttle 2 via the paper feed control unit 42.
Since the details of the timing of the inversion, constant speed, and stop control of No. 6 are described in US Pat. No. 4,819,556, the detailed description thereof will be omitted. Figure 1
It is explanatory drawing of one Example of this invention.

In the figure, the same parts as those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted. In addition, the drive circuits 52 and 54
Are respectively supplied with a voltage of 40 V from the power supply 56. The drive circuit 72 that drives the electric fan 70 for cooling the print head 22 of the impact printer and the coil 30 of the drive motor is supplied with a power supply voltage of 24 V from the power supply 56. In addition, the electric fan 74 for cooling the power supply 56 is similarly connected to the power supply 56 via the drive circuit 76.
The power supply voltage of 24V from is supplied. The print controller 50 is connected to a power supply voltage of 5V from a power supply 56.

The capacitor 62 is connected to the 40V power source output of the power source 56 and drives the coil 30 of the reversing / constant speed motor which requires overload printing of the print head 22 and a large current. , 54.
The voltage conversion circuits 80, 82, 84 are connected to the capacitor 62, respectively, and convert the electric charge accumulated in the capacitor 62 into a voltage when the power supply of the device is cut off. The detailed configuration of the voltage conversion circuits 80, 82, 84 is as shown by the voltage conversion circuit 80, as an example.
2 includes a transistor 90 connected to the collector side, a resistor 92 connecting the output of the capacitor 62 to the base side of the transistor 90, and a Zener diode 94 connecting the base side of the transistor 90 to ground. A voltage conversion circuit having a known configuration can be applied.

The output of the voltage conversion circuit 80 is connected to the electric fan 70, the output of the voltage conversion circuit 82 is connected to the electric fan 74, and the output of the voltage conversion circuit 84 is
It is connected to the print control unit 50. In the configuration described above, when the input to the power supply 56 is cut off, for example,
When the commercial power supply is cut off, the charges accumulated in the capacitor 62 are converted into voltages by the voltage conversion circuits 80, 82 and 84, and then supplied to the electric fans 70 and 74 and the print control unit 50, respectively. .

Therefore, even if the operation of each part of the device is stopped due to the power supply to the device being turned off, the electric fans 70 and 74 continue to operate, so that the printing coil of the print head 22 which is a heat generating part and The coil of the shuttle drive motor can be cooled. Therefore, even if printing is restarted after the power supply of the apparatus is restored, the heat generating portion is sufficiently cooled, so that the divided printing operation associated with the high temperature detection can be suppressed.

The print control unit 50 displays the power-off state on an operator panel (not shown) until the charge of the capacitor 62 is discharged. In the present embodiment, the capacitor 62 is discharged using all of the electric fans 72, 74 and the print control unit, but the voltage conversion circuit may be connected to only one of them.

[0021]

As described above, according to the present invention,
Since the capacitor is discharged through the electric fan, the device configuration can be simplified.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of an embodiment of an impact printer.

FIG. 2 is an explanatory diagram of an embodiment of the present invention.

[Explanation of symbols]

 52, 54 ... Load (driving circuit) 56 ... Power supply 62 ... Capacitor 80, 82, 84 Voltage conversion circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B41J 29/38 C 8804-2C 8804-2C B41J 29/00 P

Claims (1)

[Claims] 1. A load (52), a power supply (56) for supplying electric power to the load (52) through a capacitor (62), and an electric fan (70) for cooling the load (52).
And a means (80) for converting the electric charge of the capacitor (62) into a rotational driving force of the electric fan (70) to discharge the electric power when the power source of the apparatus is cut off.