JPS6135199A - Lock current supplying method of pulse motor - Google Patents

Abstract

PURPOSE:To suppress the fluctuation of a pulse motor rapidly by supplying an exciting current for locking with a current value larger than the exciting current value during operation. CONSTITUTION:A main controller 12 delivers a switching signal to a switch 19 at a timing when a rotation pulse motor 8 is locked to shift the switch as designated by a broken line to supply a reference voltage E from between resistors R1 and R2. Accordingly, the voltage E becomes a high voltage value to be supplied to an operational amplifier 18. In other words, when the motor is locked, a locking exciting current is increased larger than the exciting current during the operation of the pulse motor to generate a large torque to brake a rotational shaft fluctuated by the inertia to rapidly stop it.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for controlling excitation current of a pulse motor, and more particularly to a method for supplying lock current that can suppress oscillation of a pulse motor when it is locked in a short period of time.

BACKGROUND ART Recently, with the spread of various information processing devices, various printers have been developed and put into practical use, and when particularly high printing quality is required, a serial blink using a type wheel is used.

This serial printer uses a pulse motor as the drive source for the type wheel, and once the type selection is completed,
By locking the pulse motor, the desired type is stopped just in front of the hammer, and the hammer is driven to print.

In order to improve printing efficiency, it is necessary to drive the hammer to print immediately after character selection is completed, but at this time it is necessary that the type wheel is completely stopped.

[Conventional technology]

Figure 2 is a perspective view showing the main parts of a serial printer;
The figure is a block diagram of the control circuit of FIG. 2. The same reference numerals in the figures indicate the same objects.

As shown in Figure 2, printing paper 2 is set on platen 1, and a carriage 3 is placed in front of platen 1, on the left side of the figure.
is slidably fitted into a guide shaft 4 provided parallel to the platen 1, and the carriage 3 is similarly fitted into a feed screw 5 provided parallel to the platen IG.

The feed screw 5 is connected to a space pulse rake (hereinafter referred to as S motor) 7 via a belt 6 etc. Therefore, the feed screw 6 moves the carriage 3 guided by the guide shaft 4 by the forward and reverse rotation of the S motor 7. Arrow A in the figure.

Move in direction B.

The carriage 3 is equipped with a rotation pulse motor (hereinafter referred to as R).
A motor (referred to as motor) 8 and a hammer magnet 9 are mounted, and a type wheel 10 is detachably attached to a motor shaft (not shown).

The type wheel 10 is provided with type letters 10a extending around the entire circumference at equal pitches at the tips of radially formed arms, and by driving the R motor 8, the type wheel 10 is moved in the direction of arrows E and F in the figure. You can select the desired type by rotating it in any direction.

The hammer 9a of the hammer magnet 9 is connected to the type wheel 10.
The letter 10a is placed on the back side of the letter 6 10a at the upper end, and when the hammer magnet 9 is energized, the hammer 9a moves in the direction of arrow C in the figure to push out the letter 10a, and when the excitation is released, it returns in the direction of the arrow. It can be restored.

Next, FIG. 3 will be explained. Print information is sent from the host device to the main control section 12 via the interface circuit 11. The main control unit 12 is equipped with a liner sofa that temporarily holds print data of one stroke and a print sequence program, and based on the print information input from the ink face circuit 11, print position data, print data, hammer drive signal, and line feed data. is sent to each part for control.

The space drive control circuit 13 drives the S motor 7 to move the carriage 3 based on the print position data inputted from the main control unit 12, so that the selected desired type 10a of the type wheel 10 is at the print position. The type selection control circuit 14 controls the positioning so that the type selection control circuit 14 drives the R motor 8 based on the print data input from the main control section 12, and rotates the type wheel 10 as described above to print. Select type 10a.

The main control unit 12 completes the selection of the type 10a to be printed,
When locked in the position facing the hammer 9a in Fig. 2,
The hammer drive signal is sent to the hammer magnet drive circuit 16, the hammer magnet 9 is excited, the hammer 9a is pushed out in the direction of arrow C in FIG. and collides with platen 1 to print.

When the hammer magnet 9 is de-energized, the hammer 9a is moved backwards, and when printing of the - character is completed, print position data, print data, etc. for the next printing are sent from the main control unit 12, and the type wheel 1o moves to the carriage 3. Along with the movement, printing continues in the same manner as described above while moving in the direction of the arrow.

- When the printing is completed, the main control unit 12 sends the line feed data to the line feed control circuit 15, and the line feed pulse motor (
The LF motor (hereinafter referred to as LF motor) 17 is rotated to drive a feed mechanism (not shown in FIG. 2) to transport the printing paper 2 by a predetermined amount in the direction of arrow G.

When the LF motor 17 rotates and feeds the printing paper 2 by the line feed amount, the carriage 3 starts moving in the direction of arrow B and continues printing in the same manner as described above.

Here, the R motor 8 driven by the type selection control circuit 14 decelerates as the cycle of pulses given to each excitation phase becomes longer, and in order to stop at a predetermined rotation angle, the lock current changes to a predetermined excitation phase. supplied to

FIG. 4 is a diagram illustrating the fluctuation of the lock point of the R motor and the timing of the hammer operation.

The vertical axis S represents the amount of displacement of the rotating shaft of the R motor, and the horizontal axis t represents time. It is assumed that the R motor is decelerated as shown by the curve shown by ■ by a pulse with a longer period, and a lock current is applied at point H.

In this case, the rotating shaft of the R motor does not stop immediately due to inertia, and continues to oscillate for a while as shown by ■.

Conventionally, a hammer drive signal is sent out after a certain period of time after the lock current is supplied. For example, if the timing is indicated by J, the type 10a will be struck by the hammer 9a while the type wheel 1o is oscillating.

[Problem that the invention seeks to solve]

As mentioned above, conventionally, when trying to speed up the sending timing of the hammer drive signal in order to improve printing efficiency, printing occurs before the vibration of the R motor is completely eliminated, resulting in a problem of poor printing quality. be.

[Means for solving problems]

The above problem is solved by comparing the voltage generated in the transistor that controls the excitation current supplied to the excitation winding of the pulse motor and the resistor connected in series with the excitation winding with a reference voltage, and controlling the transistor based on the result. and a means for varying the reference voltage, the reference voltage being varied so that the current flowing through the excitation winding to lock the pulse motor is greater than the excitation current during operation of the pulse motor. This problem is solved by the method of supplying current to the current according to the present invention.

[Effect]

That is, when locking the pulse motor, the excitation current for locking is larger than the excitation current during operation of the pulse motor.
For example, by supplying double or triple the current value, a large torque is generated, and the rotating shaft, which oscillates due to inertia, is braked and stopped quickly.

〔Example〕

FIG. 1(a) is a block diagram of a circuit showing one embodiment of the present invention, which is implemented in the type selection control circuit 14 of FIG.
12 corresponds to that in FIG.

In addition, Fig. 1 fbl is a diagram explaining the operation of (al), and the vertical axis S
represents the amount of displacement of the rotating shaft of the R motor, ] represents the current value, and the horizontal axis 1 represents time.

In FIG. 1 (al), M indicates the excitation winding for one phase of the R motor 8. A signal to excite the excitation winding M is input from the main control unit 12 to the AND circuit 20. At this time, the transistor TR is turned off. Since no current flows through the current detection resistor R4, no voltage is generated at its terminal.

The operational amplifier 18 compares the reference voltage E and the voltage generated across the current detection resistor R4, and compares the voltage generated across the current detection resistor R4 with the reference voltage E.
When the voltage generated at 4 is low, it sends "1" to the AND circuit 20, and when that voltage is high (it sends "O"). Therefore, in the above case, the AND circuit 20 sends a signal to turn on the transistor TR. Send.

When the transistor TR is turned on, a current flows from the voltage tAVd to the ground via the excitation winding M, the transistor TR, and the current detection resistor R4.

At this time, the voltage generated across the current detection resistor R4 is compared with the reference voltage E input from the switch 19 by the operational amplifier 18.

Since the operational amplifier 18 operates as described above, when the voltage exceeds the reference voltage E, the operational amplifier 18 operates as the AND circuit 20.
"O" is sent to the transistor TR to turn it off.

Since the transistor TR is turned off, the current detection resistor R
When the voltage developed at 4 falls below the reference voltage E, operational amplifier 18 also sends 1'' to AND circuit 20, turning on transistor TR.

Therefore, the excitation current of a constant value regulated by the reference voltage IE as shown in FIG.
flows to This excitation current causes the R morph 8 to decelerate, for example, as shown in (2).

The reference voltage E is applied from the voltage ffi V s to the resistors R1 and R2.
The voltage is divided by R3 and supplied via switch 19. The reference voltage E when the R motor 8 is in operation is supplied from the switch 19 between the resistors R2 and R3 shown by the solid line.

At timing H to lock the R motor 8, the main control unit 12 sends a switching signal to the switch 19, switches the switch as shown by the dotted line, and sets the reference voltage E to the resistors R1 and R2.
Supply from between. Therefore, the reference voltage E has a high voltage value and is supplied to the operational amplifier 18.

The main control section 12 simultaneously sends an excitation signal to the AND circuit 20 to turn on the transistor TR.

Therefore, as shown in (■) in Fig. 1 fbl, a larger excitation current than during operation flows to the excitation winding M and brakes the R morph 8 with a large torque.In other words, as shown in (■), the vibration of the R motor is quickly suppressed. do.

Here, the main control section 12 sends out a hammer drive signal for printing at the timing indicated by J, and also stops the lock current supply.

Zener diode ZD and diode RC are activated when transistor TR is turned off. lI magnetic winding M
, and protects the transistor TR.

〔Effect of the invention〕

As explained above, the present invention supplies the J7ill magnetic current for locking at a current value larger than the excitation current value during operation of the R motor, and in order to promptly suppress the vibration of the R motor, the printing when the hammer drive signal is sent. It can prevent quality deterioration.

[Brief explanation of drawings]

FIG. 1(a) is a block diagram of a circuit showing an embodiment of the present invention; FIG. 1(a) is a diagram explaining the operation of (al); FIG. 3
This figure is a block diagram of the control circuit shown in FIG. 2, and FIG. 4 is a diagram explaining the fluctuation of the lock point of the R motor and the timing of the hammer operation. In the figure, 1 is a platen, 2 is a printing paper, 3 is a carriage, 4 is a guide shaft, 5 is a feed screw,
6 is a held, 7 is a space pulse motor, 8 is a rotation pulse motor, 9 is a hammer magneto), 10 is a type wheel, 11 is an interface circuit, ] 2 is a main control section, 13 is a space drive control circuit, 14 is a type selection control 15 is a line feed control circuit, 16 is a hammer magnet drive circuit, 17 is a line feed pulse motor, 18 is an operational amplifier, and 19 is a switch. Condolence 1 day (,4) Kaya 1st (b) δ Kaya 4 Introduction 1-I J

Claims (1)

[Claims] Comparing means for comparing a transistor that controls an excitation current supplied to an excitation winding of a pulse motor, a voltage generated in a resistor connected in series with the excitation winding, and a reference voltage, and controlling the transistor according to the result; and means for varying the reference voltage, the pulse being characterized in that the reference voltage is varied so that the current flowing through the excitation winding to lock the pulse motor is greater than the excitation current during operation of the pulse motor. Motor lock current supply method.