JPS61263784A - Residual voltage consuming circuit for printer - Google Patents

Abstract

PURPOSE:To rapidly consume a residual voltage remaining in a capacitor and avoid danger, by connecting a capacitor-discharging transistor in two stages between a load which may operate after a power switch is turned OFF and a driving transistor operated by a controlling circuit. CONSTITUTION:Of various loads 2, 3, 4 on a printer, the load 2 which may operate after the power switch 5 is turned OFF is constituted of, for example, a spacing motor. The capacitor-discharging transistor 9 provided with a small power source 13 is connected in tow stages between the load 2 an the driving transistor 9 operated by the controlling circuit 12 for the load 2. Where the transistor 9 is turned OFF by a voltage-detecting part 11 when the switch 5 is turned OFF, the transistor 10 is turned ON for a predetermined period of time by the small power source 13, whereby electric power charged in the capacitor 6 is made to flow into the load 2 consisting of the spacing motor. Accordingly, the residual voltage in the capacitor 6 is consumed by the high- capacity motor 2, whereby it is rapidly lowered.

Description

[Detailed Description of the Invention] [Summary] This is a residual voltage consumption circuit of the printer, and when the power switch is turned off, the power of the capacitor attached to the printer drive power supply is used to load the load such as a space motor that can be operated without any problem. The remaining voltage of the capacitor can be quickly consumed.

[Industrial application field]

The present invention relates to a circuit for consuming residual voltage of a capacitor attached to a power supply when the power switch is turned off in a printer such as a dot printer, and more specifically, a circuit that speeds up the consumption of residual voltage to prevent danger during maintenance. Regarding.

Generally, when a load requires instantaneous high voltage, a capacitor is provided on the power supply side, and the electrical high voltage is compensated for by the discharge of this capacitor. In addition, a dummy resistor is connected in parallel to the capacitor, so that the capacitor's power is consumed after the switch is turned off.

[Conventional technology]

Therefore, regarding the residual voltage consumption of conventional dot printers,
It is simply configured as described above.

Here, the power supply for driving a dot printer is a large power, for example, 48V, and the capacitor attached to this power supply has a large capacity.On the other hand, as devices have become smaller in recent years, there is less space available (for this reason, dummy resistors are used). The size tends to decrease.

[Problem that the invention seeks to solve]

By the way, as with the residual voltage consumption of the conventional dot printer mentioned above, in cases where the capacitor capacity is large but the size of the dummy resistor is small, the voltage consumption by the resistor is small, so it is difficult to turn off the power switch. Voltage remains for a long time after being turned off.

Therefore, when performing maintenance after the switch is turned off, there is a problem in that it is dangerous due to the presence of high residual voltage.

The present invention was created in view of these points, and provides a residual voltage consumption circuit for a printer that can speed up consumption of residual voltage and prevent danger in situations where the size of the dummy resistor is small. is intended to provide.

[Means for solving problems]

In order to achieve the above object, the present invention, as shown in FIG. Select motor.

Then, the load 2 of this space motor and its control circuit 1
A capacitor discharging transistor 10 having a small power supply 13 is connected between the driving transistor 9 operated by 2 and the driving transistor 9 operated by 2.
After the power switch 5 is turned off, a small power supply 13 is used to turn on the capacitor discharging transistor 10.

[Effect]

Based on the above configuration, when the drive transistor 9 is turned off by the disconnection special voltage detection unit 11 of the power switch 5,
When the capacitor discharging transistor 10 is turned on for a predetermined period of time by the small power supply 13, the power to charge the capacitor 6 flows to the load 2 of the space motor. In this way, the remaining voltage of the capacitor 6 is consumed by the motor load 2 having a large capacity, and can be quickly reduced.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, reference numeral 1 is, for example, a 48V printer drive power supply, 2 is a space motor, 3 is a head bin magnet, 4 is an LF motor, and power supply 1 is a power switch 5.
It is connected to supply power to various loads 2 to 4, such as motors and magnets, through the power supply. A large-capacity capacitor 6 and a large-value dummy resistor 7 are connected in parallel to the load side of the switch 5 to form a power supply circuit 8.

Therefore, if the head bin magnet 3 is driven even after the power switch 5 is turned off under the above various loads, printing errors will occur. Further, in the case of the LF motor 4, the position may shift and a line feed will occur when the switch is turned on again to print, so it is not preferable to drive the motor after the switch is turned off. On the other hand, since the space provided by the space motor 2 operates initially when the switch is turned on again, it does not matter if it moves a little after the switch is turned off.

From this, the space motor 2 is selected as the capacitor discharge load, and two capacitor discharge transistors 10 are connected between the space motor 2 and its driving transistor 9. And transistor 9
A 5V voltage detection section 11 and a motor control circuit 1 are installed on the base side of the
2 is connected, and a 5V power supply 1 is connected to the base side of the transistor 10.
It has 3. In addition, head bin magnet 3 of other loads
, the LF motor 4 is driven by each control circuit 14, 15.

Next, the operation of the circuit configured in this way will be explained.

First, when the printer is in operation, power can be supplied by turning on the power switch 5. Therefore, the 5V of the voltage detection section 11
By applying a predetermined voltage in the control circuit 12 while monitoring the
The motor is driven by electricity. Further, the head pin magnet 3 and the LF motor 4 are also energized and driven by the control circuits 14 and 15, thereby effecting printing.

On the other hand, the case where the power switch 5 is turned off when the printer is stopped will be explained using the time chart of FIG. 2. That is, when the switch 5 is turned off at time t, the power stored in the capacitor 6 begins to be consumed little by little by the dummy resistor 7. Also, at this time, in conjunction with the power switch 5, the 5v power supply 1
Since the supply of voltage 3 is also stopped, the voltage of the control circuit 12 and the voltage detection section 11 decreases, turning off the transistor 9, but the transistor 10 is turned on by the 5v power supply 13,
Therefore, the electric power in the capacitor 6 flows to the space motor 2 and is rapidly consumed and lowered due to its large load. This action takes place during the time 1. when the capacitor power becomes zero. At this time, the voltage of the power supply 13 also becomes zero, and the transistor 10 becomes O.
FF and exit.

In addition to the space motor, a line feed motor, a ribbon lift magnet, or a bail roller open/close magnet may be used as the capacitor discharge load.

〔Effect of the invention〕

As described above, according to the present invention, even in situations where the value of the dummy resistor for capacitor discharging attached to the power supply is small in order to downsize the printer, the remaining voltage is quickly consumed, making maintenance easier. This prevents the risk of danger.

Since we use the printer's load that can run after the power switch is turned off as the residual voltage consumption,
The structure is simplified and the voltage consumption efficiency is good.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the residual voltage consumption circuit of the present invention, and FIG. 2 is a time chart 1 when the power switch is turned off. In Figure 1, 1 is a power supply for driving the printer, 2 is a space motor, 3 is a herad pin magnet, 4 is a LF motor, 5 is a power switch, 6 is a capacitor, 7 is a dummy resistor, 8 is a power supply circuit, 9 10 is a driving transistor, 10 is a capacitor discharge transistor, 12 is a motor control circuit, and 13 is a 5V power supply.

Claims (1)

[Claims] From a high-power printer drive power supply (1) to various loads (2)
, (3), and (4) via a power switch (5), and a power supply circuit (8) having a large capacity capacitor (6) and a dummy resistor (7) is connected to the power supply (1). Among the various loads (2), (3), and (4) above, load (2) that can be operated after the power switch (5) is turned off.
A printer in which capacitor discharging transistors (10) having a small power supply (13) are connected in two stages between the load (2) and a driving transistor (9) operated by a control circuit (12). residual voltage consumption circuit.