JPS61106283A - Printer - Google Patents

Abstract

PURPOSE:To suppress undesired vibration of a motor and contrive higher printing quality, by taking up a synthesized signal and supplying it to a motor when stopping the motor at an objective position. CONSTITUTION:In a period T1, an addition output from an adding circuit 5 is the sum of a signal A, a signal B (c) action in the direction for accelerating the motor 1 which is taken out from a rotary encoder 2 and added by the circuit 5, and a signal C acting in the direction for decelerating the motor 1 which is taken out from a differentiator 4 and added by the circuit 5. In this case, the signal B is canceled by the component of the signal A acting in the direction for decelerating the motor 1, so that a current in the direction for deceleration is taken out as a current set point (f) for the motor 1. In a period T2, the signal B and the signal D are added by the circuit 5, and the set point (f) is rapidly reduced to zero. Thus, in the period T1, the output signal phi1 from the rotary encoder 2 slowly approaches zero. Accordingly, the period of time required for stopping the motor 1 at a printing center position is shortened, and vibrations in typing are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to printing devices such as serial printers and electronic typewriters, and particularly to servo control technology for a DC motor that drives a carrier on which a print head can be mounted.

[Prior Art] FIG. 1 is a block diagram of a damping (braking) of a motor near a printing target position and a fine position control system in a conventional electronic typewriter or the like.

In the figure, l is a DC motor, which can intermittently drive, for example, a carrier on which a print head is mounted. 2 is a rotary encoder, and when the motor 1 is rotating clockwise at a constant speed, the output signals φ1 and φ2 of the rotary encoder 2 are sine wave signals having a phase difference of 90 @ as shown in FIG. becomes. Further, when the motor 1 rotates to the left, the phase relationship between the output signals φ1 and φ2 of the rotary encoder 2 is reversed.

The signal converter 3 converts the analog output signals φ1 and φ2 obtained from the rotary encoder 2 into digital output signals F and i, and outputs the output signals 5 and 1 to the motor by a circuit not shown. Position detection 1 is used to form the rotation speed and direction of rotation.

Differentiator 4 receives output signal φ1 from rotary encoder 2
is differentiated and the output field φl' whose phase is advanced by i]0° is sent to the adder circuit 5. Here, the output φ0 of the adder circuit 5 is the output signal φ1 from the rotary encoder 2.
and the absolute value of the output signal φl' from the differentiator 4 multiplied by the gain (r3/rl).
are added, and the added value is inverted to give the following equation.

φ3-- (φIXr3/r2+φ1'Xr3/rl
) In the above formula, r1 to r3 are the resistance values of the resistors r1 to r3 connected to each part in FIG. The switch control signal 5WCON output from the anti-game) 13 when both the logical values with the output signal φ2 are "1".
This is a changeover switch that can be switched by T.

Here, when the printing target position is N and the motor 1 is rotating at a constant speed, the waveforms of each part have a relationship as shown in FIG.

In this way, the purpose of the block diagram shown in FIG. 1 is to further finely control the position of the motor l within the printing target position and to dampen its rotational speed.

The output signal of the changeover switch 6 is input to the next stage differential amplifier 7. The input signal to the differential amplifier 7 means the indicated current value of the DC motor l. Current sense resistor 8 feeds back the direction and magnitude of the current flowing through motor 1 to the input side of differential amplifier 7.

Next, when a print head (not shown) performs a printing operation,
When the motor 1 reaches the printing target position N, the waveforms of each part are as shown in FIG. What should be noted in Figure 3 is that
This is the state of the command current of the motor 1 during damping. In other words, as shown in Figure 1, the switch control signal SW G
Immediately after the ONT rises from its logical value "0" to "1", the speed dump signal C becomes the following equation regardless of the speed at which the motor l enters.

C- (φl' works effectively.

B@φI It becomes difficult to avoid overshoot, which is one of the causes of unnecessary vibrations and deterioration of printing quality.

[Objective] In view of the above-mentioned points, an object of the present invention is to realize damping control of a motor in the vicinity of the printing center position by an effective method, thereby suppressing unnecessary vibration of the motor, and improving printing quality. An object of the present invention is to provide a printing device that is improved in quality.

[Example of implementation] The present invention will be described in detail below with reference to one drawing.

FIG. 4 shows a block diagram of an embodiment of the present invention, in which parts similar to those in FIG. 1 are given the same reference numerals and detailed explanation thereof will be omitted.

In FIG. 4, 8 is a second differentiator 9 composed of an operational amplifier 9A, a resistor 3, and a capacitor 8C,
The output signal φ2 from the rotary encoder lO is differentiated. The differential signal φ2' differentiated by the second differentiator 8 is sent to one selected input of the selector switch 1O, and is also input to the inverter 11 comprised of an operational amplifier 11A, resistors 11B and 11G. The inverted output signal φ2'' from the inverter 11 is sent to the other selected input of the changeover switch lO. Switch control of the changeover switch 10 is controlled by the logic level of the output signal φl of the signal converter 3.

In such a configuration, the signal waveforms of each part are shown in FIG.
2'd, the output polarity is reversed when the motor 1 rotates clockwise and counterclockwise.

Next, FIG. 8 shows the damping waveform and the current waveform to motor 1 when motor 1 rotates clockwise and stops. In this case,
Switch control signal SW supplied from AND gate 13
Immediately after C0NT rises from its logical value "ON" to "1", the output signal φ1 from the signal converter 3 is '0°.
For this reason, the contact point of the function switch 10 shown in FIG.

Therefore, the signal A acting in the direction of deceleration of the motor 1, taken out from the changeover switch shown in FIG. 6 and added by the adding circuit 5, becomes a linear expression.

8-(φ2'X r3 / r4) Here, r3 and r4 in the above formula represent the respective resistance values of the resistors r3 and r4 connected to the adder circuit 5.

Therefore, in one period T1, the addition output of the addition circuit 5 is, in addition to the above-mentioned signal A, the above-mentioned signal B which acts on the acceleration direction of the motor 1, which is taken out from the a-tary encoder 2 and added by the addition circuit 5. , and the above-mentioned signal C which acts in the direction of deceleration of the motor 1 which is taken out from the differentiator 4 and accelerated by the addition circuit 5 are added.
As shown in the figure, since the signal B is canceled out by the component of the signal A that acts in the deceleration direction, the current in the deceleration direction as shown in the figure is extracted as the current instruction value for the motor 1.

Next, in period 2, the contacts of the changeover switch 10 are selected to the state shown in the figure, so the output signal φ2' from the inverter 11 is received, taken out from the changeover switch 10, and added by the adder circuit 5. The signal is given by the following formula.

D--(φ2' X r3/r4) Therefore, the period T
2, the signals B and O are added by the adding-X circuit 5, and the current command value of the motor 1 suddenly becomes zero as shown in the figure.

In this way, according to the embodiment, during the period TI, the damping (deceleration) component of the signal A effectively acts on the signal B, and a current component in the deceleration direction that is approximately proportional to the rush speed is added to the command current. do. Therefore, when focusing on the output signal φ1 of the rotary encoder 2 in FIG. 8, it can be seen that it approaches zero while attenuating more slowly compared to the waveform of the conventional system shown in FIG. Therefore, compared to the conventional method.

The time required for the motor 1 to come to rest at the printing center position is shortened, and vibrations during damping can be reduced.

The present invention is not limited to one or more embodiments;
As shown in the figure, in the period child 1, only the component in the deceleration direction is taken out from the changeover switch 6 as the current instruction value for the motor l.

Therefore, it is also possible to take out only the speed dump signal C shown in FIG. 6 as the current instruction value for the motor l.

[Effect] As explained above, according to the present invention, damping control is appropriately performed when stopping the motor at a target position, so unnecessary vibrations when stopping the motor are suppressed. At the same time, it is possible to improve the printing quality.

[Brief explanation of drawings]

Figure 1 is a block diagram showing an example of the configuration of a control system of a conventional device; Figure 2 is a waveform diagram showing an example of the waveforms of each part of the block diagram shown in Figure 1; Figure 3 is the waveform diagram shown in Figure 1. FIG. 4 is a block diagram showing an example of the control system of the device of the present invention, and FIG. FIG. 3 is a waveform diagram showing an example of waveforms of each part of the illustrated block diagram. FIG. 6 is a waveform diagram showing an example of waveforms of various parts when the motor reaches the printing target position in the block diagram shown in FIG. 4. 1...Motor, 2...Rotary encoder, 3...Signal converter. 4... Differentiator, 5... Addition circuit, 8... Selector switch, 7... Differential amplifier, 8... Resistor. 8... Differentiator, 10... Selector switch, 11... Inverter, 13... AND gate.

Claims (1)

[Claims] 1) A motor that drives a carrier on which a print head can be mounted, and a signal generating means that detects the rotation of the motor and generates first and second signals with different phases in accordance with the rotation. and acceleration signal generating means for forming a signal in a direction to accelerate the rotation of the motor based on the first signal; and deceleration signal generating means for forming a signal in a direction to decelerate the rotation of the motor in accordance with the first signal. and canceling signal generating means for forming a signal using the second signal to cancel the signal obtained by the acceleration signal generating means, and a signal from the acceleration signal generating means, the deceleration signal generating means and the canceling signal generating means A printing apparatus comprising: means for outputting a composite signal obtained by combining each output signal; and means for extracting the composite signal and supplying it to the motor when the motor is stopped at a target position. 2) A motor that drives a carrier on which a print head can be mounted, a signal generating means that detects the rotation of the motor and generates a signal corresponding to the rotation, and a signal from the signal generating means that controls the rotation of the motor. The motor is characterized by comprising a deceleration signal generating means for forming a signal in the direction of deceleration, and a means for extracting a deceleration signal from the deceleration signal generating means and supplying it to the motor when stopping the motor at a target position. printing device.