JPS62122760A - Spring charge type printing head drive system - Google Patents

Abstract

PURPOSE:To shorten wire returning time after printing head wire impact, suppress secondary vibration, enable settings to be performed in a short time, thus contributing toward fast response and improved stability by applying an electric current in opposite direction to a printing direction to a wire drive solenoid coil after wire impact. CONSTITUTION:If an input signal reaches 'L' level at time t=t0, an output from buffer IC B1 will go to 'H' level, turning transistors Q1, Q2 and Q5 ON, and an electric current I1 will run through an solenoid coil L1. Next when it is time t=t1, the input signal reaches 'H' level, setting transistor Q2 to 'OFF' position. Consequently, an electric current I2 is applied to the solenoid coil L1 through a loop of diode D2, solenoid coil L1 and transistor Q5. When it is time t=t2, a loop current 13 runs to the solenoid coil L1 via a power supply + V. When this current 13 has completely disappeared, outputs from buffer ICB4 and B2 will go to 'H' level, if an input signal 103 is set to 'L' level. Further, an electric current 14 will run through the solenoid coil L1. If the input signal 103 is set to 'H' level at time t=t4, a loop current 15 is applied to the solenoid coil L1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for driving a spring-charged print head, and more particularly to a method for controlling a wire-driving electromagnetic coil when the print head returns after a wire impact.

2. Prior Art Conventionally, in this type of drive system, printing was controlled by unidirectional energization of the drive electromagnetic coil of the print head wire. That is, the drive electromagnetic coil was not controlled after the print head wire impact.

Problems to be Solved by the Invention Therefore, in the conventional drive system described above, the return time after the print head wire impact and the secondary vibration generated after the wire return are all determined by constants of the mechanical system. There was a drawback in that the high-speed response of the head wire and the suppression control of secondary vibration were determined by the mechanical system described above.

The unexploded aA was created in order to eliminate the above-mentioned drawbacks inherent in the conventional technology.Therefore, the object of the present invention is to apply a current in the opposite direction to the printing direction to the wire drive electromagnetic coil after the print head wire impact. To realize a new print head drive method that shortens the wire return time after wire impact, suppresses secondary vibration, and settles in a short time, and improves high-speed response and stability. It is in.

Means for Solving the Problems In order to achieve the above object, the spring charge type print head drive system according to the present invention provides a spring charge type print head drive circuit in which the wire is driven after the wire drive current flows. The IJ magnetic coil is provided with a printing wire return control means for flowing a control current in the opposite direction to the wire and drive current.

Embodiment Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.

In FIG. 1, reference numeral Lll indicates a wire driving electromagnetic coil, and the electromagnetic coil Ll is completely bridge-connected by power amplifying transistors Q2, Q3, Q4, Q5. By input signals 101 to 103 via B4! It is driven at the timing shown in FIG. Transistors Q3, Q4, Q
6. Buffers ICB2 and B4* constitute a printing wire return control circuit which is the main part of the unexploded BAO.

When the input signal 101 goes to the ``L'' level at time t=to, the output of the buffer ICB1 goes to the ``H level'', turning the transistor Ql ``ON''. From this nV, the transistor Q2 turns 0 ON''. On the other hand, as shown in FIG. 2 at time t=to, since the input signal 102 is at the "L" level, the transistor Q5 is turned on (1), and current II in FIG. 1 flows through the electromagnetic coil LIK. .Next, time t
= tl, the input signal 101 becomes H" level, and
Therefore, transistor Q2 becomes 0 off.For this reason,
11 The electric current 2 flows through the magnetic coil Ll through a loop of the diode )-p2, the ims coil Ll, and the resistor Q5.

Since the input signal 102 becomes @IH1'' level at time t=12, a current I3 flows into the magnetic coil L1 via the diode D2, the electromagnetic filter L1, and the diode D3.

If the input signal 103 is set to 1L" level at time t=ts after this current generator 3 has sufficiently disappeared, the buffer IC
The outputs of B4 and B2 become H" level, which causes transistors Q6 and Q4 and at the same time transistor Q3 to
is turned on 1'', and the electromagnetic coil LIK is turned on at I4.
A current flows. When the input signal 103 is set to ``H'' level at time t==b, transistors Q4 and Q3h''
OFF”, and the electromagnetic filter LIK becomes diode D4,
A loop current 5 flows through the electromagnetic coil LL and the diode Di.

FIG. 3 shows the current II to step 5 flowing through the electromagnetic filter Ll,
This shows the motion waveform of the wire when driving the electromagnetic coil, and the current 301 (
The movement of the wire begins at time t= (wire drive current), and when the displacement JIK is reached, the wire begins to return to its initial position (J=0). In this embodiment, the return of the wire is performed by the magnetic force of the magnet that attracts the armature, but the current applied to the electromagnetic coil is also reversed at time t=t4, that is, the current I4 is changed after time t4.
, I5 ensures that the wire returns by flowing a control current 303 in the opposite direction to the wire drive current 301.

According to the current waveforms 301 and 303 of the electromagnetic coils, the wire displacement waveform 302 is obtained as described above.

The timings t4 and ta are determined by the mechanical movement waveform (specific) of the wire so as to suppress the wire displacement waveform, particularly the rebound 304, as much as possible.

As described above, according to the present invention, in a spring-charged print head, a W flow in a direction opposite to the normal wire impact is caused to flow through the wire drive electromagnetic coil in consideration of the motion waveform after the wire impact. In particular, it is possible to improve the wire response speed, suppress the secondary vibrations generated when the wire is returned, and shorten the settling time of the secondary vibrations.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an electromagnetic coil drive circuit according to the present invention. R1, R4...Resistance between base and emitter of transistor, R,2, R6, R7, 几8-...Pull-up resistor,
R3, R5...Current limiting resistor, Ql-Q5/number-transistor, Dl~D4...diode, Bl~B4/
... Buffer IC, 1ot-103... Input signal, 10 - Working I source voltage, Il ~ Engineering 5... 1i IL magnetic coil drive current, Ll -... Electromagnetic filter Figure 2 shows the electromagnetic filter of the present invention. FIG. 3 is a diagram showing input signals to the drive circuit. t@...Time (to~ta) Fig. 3 is a diagram showing the electromagnetic coil, drive current, and wire movement waveform. 301 , 303 , II to I5...'ts coil drive current, 302... wire movement waveform, 304...
Wire secondary vibration waveform

Claims (1)

[Claims] A spring charge type print head drive circuit, characterized in that the spring charge type print head drive circuit is equipped with a print wire return control means for flowing a control current in a direction opposite to the wire drive current to the wire drive electromagnetic coil after the wire drive current flows. type print head drive system.