JPS58108171A - Driving mode for spring charge type wire printing head - Google Patents

Abstract

PURPOSE:To permit the highspeed drive of a printing wire as well as to reduce the consumption of electric power by a method in which when an armature is restored after the printing, attracting current is flowed to an electromagnetic coil, attracting magnetic flux is increased temporarily, and the restoring time is shortened. CONSTITUTION:An armature 4 attracted by a core 5 by the attracting magnetic flux of a permanent magnet 1 is released by flowing a current to erase the magnetic flux to the electromagnetic coil 7. By this, a printing wire 9 is driven for printing. At about a time when the armature 4 begins to come back toward its home position after printing, an attracting current in the direction of generating magnetic fluc in the same direction as the attracting magnetic flux is flowed in the electromagnetic coil 7 until the restoration of the wire 9 is properly accelerated, and thereby the wire 9 and the armature 4 are restored with high speeds. Also, immediately before the collision of the armature 4 restored with high speeds against the core 5, an attracting current is flowed for a preset time period once more to control the rebound of the armature 4 restored with high speeds.

Description

[Detailed Description of the Invention] The present invention involves attracting a shear ant mature by a permanent magnet, biasing a leaf spring, and then passing a current through an electromagnetic coil in a direction that cancels out the magnetic flux attracted by the permanent magnet, thereby releasing the armature. The present invention relates to a method of driving a so-called spring-charged wire printing device that drives a printing wire.

For spring-charged wire printing, the magnetic flux of the permanent magnet 1 is connected to the side yoke 2. Upper yoke 3. Marketing Mature 4. A loop τ passing through the core 5° and the lower yoke 6 is formed, and an attractive force is generated in the armature 4, biasing the leaf spring 8, storing strain energy in the leaf spring 8, and the armature 4 is attracted to the core 5. At this time amateur 4
Assuming that the displacement of the printing wire 9 located at the tip of is zero, x=
Amateur 4.0 position. As the home position of the printing wire 9, the displacement of the printing wire 9 in the printing direction shown in FIG. 1 is assumed to be X. The force of attraction, displacement
p (x) and the force of leaf spring 8, Neka Fa (x), and the spring force of leaf spring 8 are overcome to move amateur 4 to core 5.
The force of adsorption to, Tsuma Shigure Road PL (X)” FP
The dependence of (x) -Fs (x) on the displacement X is given as shown in FIG.

Amateur 4 attracted to home decision in this way
．． A conventional driving method for printing and driving the wire 9 will be explained using a specific example. An example of the drive circuit is shown in FIG. 3, and a conceptual diagram of the drive current waveform and operation waveform at this time is shown in FIG. Here, the horizontal axis is time, and the vertical axis is drive current Js, displacement x1 of the printing wire 9, magnetic flux φP (, ), magnetic flux attracted by the permanent magnet 1, magnetic flux φP
Coil magnetic flux φ6 that cancels out (x), eddy current magnetic flux φ generated in core 5 due to back electromotive force. It shows. In order to operate the spring-charged wire or wire head shown in Fig. 1 in multiple ways using the drive circuit shown in Fig. 3, two transistors Trl shown in Fig. 3 are required.
e It is sufficient to turn on Tr2 at the same time, and in this way, the coil magnetic flux φ generated by the electromagnetic coil 2 in Fig. 1 increases with time, and the preload p at x = 0
When the value that cancels L(o) is reached, the printing wire 9 together with the armature 4 shown in FIG. 1 starts to move as shown in FIG.
The coil magnetic flux φ increases while canceling the attraction magnetic flux φP←), and is almost equal to the coil magnetic flux φ. When becomes equal to the attractive magnetic flux φF (0) shown in FIG. 2 (that is, at time TI in FIG. 4), the transistor Tr1 in FIG. 3 is turned off.
FF, and at this time, using the back electromotive force generated from the electromagnetic coil 7, a current is circulated from the electromagnetic coil 7 to the diode D2 and the transistor Tr2 in a direction that cancels the attractive magnetic flux φP(X), and the printing wire 9 is When the speed of the printing wire 9 reaches a value that obtains the necessary printing force (
That is, at time Tz) in FIG. 4, the transistor Tr2 in FIG. 3 is turned off. At this time, the back electromotive force generated in the electromagnetic coil 7 passes from the electromagnetic coil 7 through the diode D2,
Power supply, diode D! The energy is returned to the power source. Printing wire9. and Amateur 4 finished printing,
He was repulsed and began his return to his home base.

During this return process, the preload PL (X
) The ball accelerates as it returns to the home position and rebounds.

Now, in order to speed up the conventional method, the sum of the impact time Ti and return time Tr, that is, the printing wire reciprocating time Te must be shortened.
The conventional method of returning the armature 4 by preload P L (X) has fundamental drawbacks as detailed below.

In other words, in the conventional type, the return force of the armature 4 is obtained from the preload PL(x), so in order to shorten the return time Tr, the preload PL(X) must be increased, and therefore the drive current id must be increased. Must. However, when the drive current id is increased, the temperature of the print head increases,
Eventually it will burn out. Therefore, the magnitude of the drive current 6d is limited by the heat resistance of the print head, and the preload P L
The magnitude of (X) is limited by this drive current 4.1. Also, when the pre-low PPL←) is increased, the coil magnetic flux φ increases. must also be increased, but the electromagnetic coil 7
Since there is a delay due to the time constant of the coil magnetic flux φ. It takes a long time for the magnetic flux to reach a predetermined amount of magnetic flux, so the impact time Ti becomes long. Therefore, preload PL (
Even if x) is increased as much as possible and the return time Tr is shortened, the printing wire reciprocating time Tc is not shortened by the same amount and has the disadvantage that it cannot be made faster. It also had the disadvantage of high power consumption.

Therefore, the present invention aims to reduce the preload and shorten the impact time and return time, and for this purpose, a current is applied to the electromagnetic coil in a direction that cancels out the magnetic flux attracted by the permanent magnet to drive the printing wire. A current is caused to flow in the electromagnetic coil in the opposite direction to that during driving near the time when it starts returning toward the home position, and will be described in detail below with reference to the drawings.

FIGS. 5, 6, and 7 show examples of drive circuits that implement the drive method of the present invention. First, the case of driving using the driving circuit shown in FIG. 5 will be explained in detail. A conceptual diagram of the operating waveforms at this time is shown in FIG. When driving the printing wire 9, as in the conventional case, the transistor Trl e 'rr2 shown in FIG. , and cancel out the attractive magnetic flux φP←). Coil magnetic flux φ
. When the value of the preload pL(o) at x = 0 (the home position of the print wire 9 and the amateur 4) is reached, the print wire 9. of FIG. Amateur 4 starts moving, the current increases further, and the coil magnetic flux φ. When the magnetic flux φF(0) at X=O is canceled out (that is, time T1 in FIG. 8), the fifth
The transistor Tr2 shown in the figure is turned off, and the back electromotive force generated in the electromagnetic coil is circulated from the electromagnetic coil 7 through the diode D3 to the transistor Trl, and the printing wire 9 and armature 4 are accelerated and driven. ,
When the speed of the printing wire 9 reaches a value at which the required printing force can be obtained (that is, at time T2 in FIG. 8), the transistor Tr1 is turned off. At this time, the back electromotive force generated in the electromagnetic coil is transferred from the electromagnetic coil to the diode D3,
It circulates through the power supply to diode D2, returning energy to the power supply. Everything up to this point is exactly the same as before. Next, at the time when the printing wire 9 starts to print (that is, time Ts in FIG. 8), the transistor Trl m-Tr4
is simultaneously turned on, and an attraction current j11 is applied to the electromagnetic coil 7 in a direction that generates a magnetic flux in the same direction as the attraction magnetic flux φP← (that is, in a direction opposite to that during driving). As a result, the total amount of magnetic flux that attracts the armature 4 to the core 5 increases, and the return of the printing wire 9 is accelerated. In this way, at the time when an appropriate acceleration is obtained (that is, time T4 in FIG. 8), the transistor Tr4 is turned off, and the back electromotive force generated in the electromagnetic coil 7 at this time is transferred from the electromagnetic coil 7 to the diode in FIG. D! , to the transistor Tr3, further accelerating the return of the amateur 4. Next, at an appropriate time before the armature 4 collides with the core 5 (
That is, at time Ts in FIG. 8, the transistor Tr3 is turned off. At this time, the back electromotive force generated in the electromagnetic coil 7 is circulated from the electromagnetic coil 7 to the diode Dl, the power source, and the diode D2, and the back electromotive energy is returned to the power source. Further, at a point in time near when the printing wire 9 and the armature 4 return to their home positions (i.e., time Ta in FIG.
) to turn on transistors Tr3 and Tr4 simultaneously again.
Then, the current in the opposite direction to that during driving, that is, the attraction current i
t2 is applied to the electromagnetic coil to attract the armature 4 and suppress the rebound.

At this time, since the gap between the armature 4 and the core 5 in FIG. 1 is very small, only a small amount of attraction current it2 is required. After the time required to press the reband (i.e. the 8th
At time Tr in the figure, the transistor Tr3 aT in FIG.
ra is turned off at the same time, and the back electromotive force generated in the electromagnetic coil 7 is transferred from the electromagnetic coil 7 to the diode DI.
,! E source, diode) 7D2, and the back electromotive energy is returned to the power source.

Note that as the attraction current it1 increases, the return time can be shortened, but the rebound force also increases. Therefore, it is preferable to set the amount of current to an extent that cancels out the eddy current magnetic flux φ8.

As described above, according to this embodiment, the suction current id at the time of return
Since it was made to temporarily increase the attractive magnetic flux and shorten the return time, Greroad PL Den) is Amateur 4
It only needs to be small enough to be able to attract the core 5 to the core 5. Therefore, the drive current can be reduced to the conventional A level, and the impact time Ti can also be shortened. Also, the suction current is 8t.
Since 1 is smaller than the drive current id, both the overall resistance loss and iron loss are 1/3 degrees compared to the conventional case, and the power consumption is reduced.

In the above-mentioned embodiment, rebound is suppressed by flowing the attraction current it2 for a certain period of time immediately before the armature 4 collides with the core 5, so that there is an effect of stable operation during continuous high-speed printing. In other words, if the armature 4 is returned to its original position at high speed as described above, there is a risk that the rebound will be large, and variations in print density and dot removal may occur.However, in this embodiment, the attraction current ff1tz is applied to temporarily reduce the attraction magnetic flux. The rebound of amateur 4 is suppressed.

FIG. 6 is a circuit diagram showing the second embodiment, and the circuit is simplified by using two power supplies. As for operation, transistor Trl is turned on, transistor Tr2 is turned off.
F, the drive current i (1 flows through the electromagnetic coil 7,
Transistor Tr! OFF, ) transistor Tr2 is turned OFF,
This embodiment differs from the first embodiment in that when set to N, an attraction current it flows through the electromagnetic coil 7. The Zener diodes ZD and Zn2 are used to improve the cutting of the drive current id and attraction current it, and are used to adjust the operating characteristics of the printing wire by changing the Zener voltage.

FIG. 7 is a circuit diagram showing the third embodiment, in which the electromagnetic coil 7 is divided into two parts to simplify the circuit. The operation is similar to that shown in FIG. 6, but by changing the number of turns N1 and N2 of each of the divided electromagnetic coils 7, the driving current id and the attraction current it can be adjusted individually.

Furthermore, the control circuit that controls the circuits shown in FIGS. 5, 6, and 7 is a microcomputer M as shown in FIG.
An interface circuit LF (I10 port) for connecting the PU, a ROM (!J = de-only memory) storing the program and data for achieving the control sequence, and the transistors Trl to Tra etc. and the microcomputer MPU. ). A flowchart in this case is shown in FIG.

As explained in detail above, according to the present invention, first, a driving current is applied to the electromagnetic coil in the direction of canceling the magnetic flux attracted by the permanent magnet to drive the printing wire, and then the r
Since a suction current in the opposite direction to the drive current is applied to the electromagnetic coil in the vicinity to accelerate the return of the printing wire, the printing wire can be driven at high speed and has the effect of reducing power consumption. .

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing /J net charge type wire printing, and Figure 2 is a conceptual diagram of the net charge type wire print head and the general dependence of various parameters on displacement X. 3 is a circuit diagram showing an example of a drive circuit using a conventional drive method, and FIG. 4 is an operational waveform diagram of a spring-charged wire print head when driven by the drive circuit shown in FIG. 3. 5 is a circuit diagram showing a first embodiment of the present invention, FIG. 6 is a circuit diagram showing a second embodiment of the present invention, FIG. 7 is a circuit diagram showing a third embodiment of the present invention, and FIG. The figure is an operational waveform diagram of the spring charge type wire print head when driven by the circuit shown in Fig. 5, Fig. 9 is a block diagram showing the configuration of a control circuit that controls the circuit shown in Fig. 5, and Fig. 10 is a block diagram showing the configuration of a control circuit that controls the circuit shown in Fig. 5. The figure is number 9
3 is a flowchart of the control circuit shown in the figure. , 1... Permanent magnet, 2... Side yoke, 3... Upper yoke, 4... Amateur, 5... Core, 6...
・Lower yoke 7... Electromagnetic coil, 8... Leaf spring, 9
...Printing wire, 10...Printing wire guide, Tr
la Trz, Tr3 and Tr4...transistor, DB e D2 e Da and D4 are diodes, ZDI and Zn2...zener/(ode, MPU...microcomputer, ROM...read only memory, IP...・Interface circuit. Fig. 3 Fig. 4 (Ink punching wire 4 Y f1 Koji) F Fig. id:, J%!! Dynamic current iw: tli+/Current Fig. 8 L-J

Claims (1)

[Claims] The permanent magnet attracts the shear to mature, and at the same time biases the leaf spring, sets the amateur to the home position, and applies current to the electromagnetic coil in a direction that cancels out the magnetic flux attracted by the permanent magnet. In the spring-charged wire printing method, which releases the armature and drives the printing wire located at the tip of the armature, the printing wire is driven by passing a current in the direction of canceling the magnetic flux attracted by the permanent magnet through the electromagnetic coil. . A method for driving a spring-charged wire print head, characterized in that a current in a direction opposite to that during driving is passed through the electromagnetic coil near the time when the print head starts returning toward the home position.