JPS60164309A - voltage correction circuit - Google Patents

Abstract

PURPOSE:To enable correction of hammer voltage at a constant threshold value by correcting the hammer voltage of a printer due to switching of disconnecting means provided for disconnecting resistance provided in series with grounding side resistance. CONSTITUTION:Of dividing resistance R1+R2 connected between power source voltage VD and the ground, grounding side resistance R2 is inserted with resistance R3 in series and a transistor 12 for switching is provided in parallel with the resistance R3. In this construction, in the case of printing speed change, e.g., if switching of the power source voltage in two steps is required, Von, Voff applied to the both ends of a condenser 5 are shown by Formulae I , II by switching due to insertion of a short-circuit plug in the base bias of the transistor 12 and appropriate timing for required two speeds can be obtained by previously selecting the resistance R1, R2, R3. That is, similar effect to switching in two steps of the power source voltage VD can be obtained by on-off of the transistor 12 and if the resistance R1, R2, R3 are previously set appropriately, required hammer start timing can be obtained by only switching the transistor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention is directed to disconnecting a capacitor circuit provided in parallel to the ground side resistor of a piezoelectric resistor between a power supply voltage and the ground, and converting the generated waveform to a predetermined threshold value. This relates to a voltage correction circuit that controls the printer's hammer speed at the timing of slicing.

(2) Prior Art and Problems Conventionally, the printing speed of belt-type impact printers is different from 500, 600, 900, and 1200 lines/min. In this case, changing the driving time of the hammer alone cannot supply enough energy, so changing the driving voltage,
Additionally, the threshold for creating Banma Taimink was changed.

FIG. 1 is an explanatory diagram of the configuration of a conventional example. A voltage dividing resistor consisting of a resistor (Ri) 1 and a resistor (Re) 2 is provided between the drive voltage Vn and the ground, and from the voltage dividing point α to the resistor (Ra ) 3 and a diode (DI) 4, point b is connected to the capacitor (
C) Connect the point b to the negative terminal of the comparator 7, and connect the predetermined threshold value Vraf to the positive terminal of the comparator 7.

In addition, the 0 point is a switch transistor with a common emitter (
Ql ) 6 is connected to the collector of this transistor 6
Add on/off input signal ■ to 0 base.

With this configuration, as will be described later in FIG. - The capacitor 5 is charged through the path of the capacitor (C) 5 to show a rising waveform, and the current (1
2) is discharged from the capacitor through the path of capacitor (0) 5 - resistor (R3) 5 - transistor (Ql) 6 and becomes T.
The i waveform is shown. Such rising and falling waveform signals are input to the negative terminal of the comparator 7 and compared with the threshold value Vnf of the positive terminal, and an output signal (psg) in which the portion where the input signal exceeds the threshold value Vrgl becomes an on-pulse is extracted.

At the start-up point of this on-pulse, it is necessary to adjust the threshold values V and f along with a change in dynamic voltage that does not depend on the printing speed, so it is difficult to set the desired printing speed and requires a complicated configuration and operation procedure. It was necessary.

(3) Purpose of the Invention The purpose of the present invention is to correct the hammer voltage at the timing when the capacitor circuit installed in parallel with the ground side resistor of the voltage dividing resistor between the drive voltage and the ground is disconnected, and the generated waveform is sliced at the threshold value. In this case, it is an object of the present invention to provide a voltage correction circuit that can correct the hammer voltage while keeping the threshold constant.

(4) Structure of the Invention In order to achieve the above-mentioned object, the voltage correction circuit of the present invention connects or disconnects a capacitor circuit provided in parallel to the ground side resistor of the voltage dividing resistor between the drive voltage and the ground by a switch means. At the timing when the generated voltage waveform is sliced at a predetermined threshold value, in a voltage correction circuit that corrects the hammer voltage according to the printing speed of the printer, the resistor connected in series with the ground side resistor is disconnected. The present invention is characterized in that the hammer voltage of the printer is corrected by switching the connecting/disconnecting means.

(5) Examples of the invention FIG. 2 is an explanatory diagram of the configuration of an embodiment of the present invention.

In the figure, the difference from Figure 1 is that a resistor R3 is inserted in series with the ground side resistor R2 of the voltage dividing resistors R1+R2 connected between the power supply voltage VD and the ground, and a switch for the switch is inserted in parallel with this resistor R3. A transistor (Q2) 12 is provided.

In this configuration, the printing speed is 300°6 as described above.
00, 900, 1200 lines/min, etc., for example, if you want to switch the power supply voltage in two stages, you can insert a shorting plug into the base bias of transistor p(Qz)12 and switch it. 0)・50 The voltages Vea and Voff applied to both ends are when Q2 is off. vo//= """" (1) R1+R20B.

When Q2 is on, v = 2 kVD (2) R10R2 In this way, by selecting the resistors R1v B'2 v R3 in advance, it is possible to obtain appropriate timing corresponding to the two predetermined speeds.

FIGS. 3A to 3C are explanatory diagrams of the principle of the present invention.

The figure (cL) is an input signal to the base of the transistor (Qθ6).

For example, a pulse of T1 on and T2 off is applied in response to a clock with a period T that often occurs when belt type type moves. As a result, the transistor 6 is turned on and off, and the above-mentioned charging/discharging circuit is activated, as shown by the solid line ■ in Figure (6).
When T1 is turned on, charging starts and the voltage rises to the saturation voltage.
When T2 is turned off, the discharge begins and decreases. And the threshold V
Lo f at P8E in the same figure (C) when slicing with rd
Used as the 1E hammer start timing. On the other hand, the driving voltage ■. If the voltage is high, the waveform becomes waveform 6, and if it is low, the waveform becomes waveform 6. Since the saturation voltage is different, the slope of the decline is different.
Change it like this.

This makes it possible to make the energy applied to the hammer almost uniform, so it is possible to compensate for fluctuations in the drive voltage to some extent, and it is sufficient to change the threshold value, but it cannot accommodate multiple printing speeds. To deal with this, the driving voltage is switched in two stages, for example, and threshold values are set for each stage, but the configuration becomes complicated.

Therefore, in the present invention, as shown in equations (1) + (2), the same effect as switching the power supply voltage Vo in two stages by turning on and off the transistor 120 can be obtained by changing VO7/, Van#), and There is no need to adjust Vn and Vr, and the desired hammer start timing can be easily obtained by setting the resistors R1, R2, and R3 appropriately in advance and simply switching the transistor 12. It is also possible to switch to multiple stages using a similar method.

(6) Effects of the Invention As explained above, according to the present invention, the waveform generated by disconnecting and disconnecting the capacitor circuit provided in parallel with the ground side resistor of the voltage dividing resistor is sliced, and the hammer start timing of the printer is adjusted. In this case, the printer's hammer voltage is corrected by setting the threshold value to a constant value t by switching an electronic switch to short-circuit a resistor connected in series with the ground-side resistor.

Therefore, unlike conventional methods, it is not necessary to use a complicated adjustment method of changing a threshold value, but by simply switching a preset circuit, it is possible to obtain the hammer start timing corresponding to each printing speed with a simple operation.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of the conventional example, FIG. 2 is an explanatory diagram of the configuration of the embodiment of the present invention, and FIG. 3 is an explanatory diagram of the operation of the embodiment of FIG. .11 is a resistor, 4 is a diode,
5 is a capacitor, 6.12 is a transistor, and 7 is a comparison circuit. Patent Applicant Fujitsu Limited Sub-Agent Patent Attorney 1) Yoshishige Saka M1 Figure 11 Figure 2 V.

Claims (1)

[Claims] A capacitor circuit provided in parallel with the ground side resistor of the voltage dividing resistor between the driving voltage and the ground is disconnected by a switch means, and the generated voltage waveform is sliced at a predetermined threshold value. In the voltage correction circuit that corrects the hammer voltage according to the printing speed of the printer at the timing when the printer prints, a disconnection stage is provided to short-circuit the resistor connected in series with the ground side resistor and the printing resistor. A voltage correction circuit characterized in that a hammer voltage of a printer is corrected by switching a connecting/disconnecting means.