JPH07115520B2 - Drive controller for dual drive system - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when changing the rotational speed of a print head motor, drives a first drive mechanism by the rotation of the motor and drives a second drive mechanism at a predetermined drive timing. The present invention relates to a drive control device for driving in synchronization with the motor by a pulse.

2. Description of the Related Art Conventionally, a printer having the above-described two-system drive mechanism, for example, a serial printer such as an inkjet printer that prints a printing member provided on the print head at a predetermined timing in accordance with movement of the print head that is moved by rotation of a motor In, when the speed constant of the print head motor and the time constant of the print timing pulse are individually calculated and the speed of the print head motor is changed,
In response to this, the time constant of the print timing pulse generation circuit is switched and changed.

Problems to be Solved by the Invention However, in the conventional inkjet printer configured as described above, there is no inconvenience when the number of speeds to be set is small, but when the number of speeds to be set is large, the division ratio is large. Becomes larger, the frequency of the reference clock becomes higher, and the IC
Response speed is insufficient, and in general frequency division, the speed changes with 1/2 ⁿ , so there is a drawback that the speed cannot be changed finely. There is a problem that the number of types of constants increases, switching becomes complicated, and it is not practical in terms of cost.

Means for Solving the Problems In order to solve the above problems, the present invention generates a predetermined frequency from a frequency divider based on speed information from a speed information generator, and determines the frequency and the rotation speed of a motor. Of a means for setting the motor to a speed that matches the speed information by a frequency difference proportional to, and a phase of the frequency of the print timing pulse set by the speed information and a frequency proportional to the rotation speed from the motor. And a means for matching the phases.

Operation According to the present invention, the clock of the frequency fs from the frequency divider set by the speed information is input to the speed comparator, and the speed phase comparator, low-pass filter, motor drive device,
The print head motor is rotated at a rotation speed that synchronizes both speed and phase by a phase-locked loop consisting of a motor, encoder, and waveform shaper, and the time constant set by speed information is input to the voltage-controlled oscillator for printing. The pulse from the encoder of the head motor is input to the phase comparator, and the phase of the print timing pulse is set by the phase lock loop including the phase comparator, the low pass filter, the voltage controlled oscillator, and the frequency unit.

First Embodiment FIG. 1 is a block diagram of a print control device for an ink jet printer according to a first embodiment of the present invention, in which a frequency fx from a reference oscillator 1 is divided into a frequency fs set by speed information from a speed information generator 2. The frequency is divided into M / 2 ^n-1 by the frequency divider 3, and the frequency fs thus divided is input to the velocity phase comparator 4. In the speed phase comparator 4, the rotational speed of the print head motor 7 is detected by the encoder 8 and compared with the frequency fg shaped by the waveform shaping circuit 9, and the signal of this difference is input to the low pass filter 5 to be a low frequency signal. Only the low frequency signal is passed and an output is output from the motor driving device 6 to set the print head motor 7 to the rotation speed determined by the speed information.

On the other hand, the speed information is input to the time constant setting circuit 10, the time constant of the frequency fc of the voltage controlled oscillator 11 is changed by the output from the time constant setting circuit 10, and the printing timing of the frequency f ₀ from the voltage controlled oscillator 11 is changed. The pulse is input to the print head, and this print timing pulse is 1 / N in the frequency divider 12.
And is input to the phase comparator 13. Further, the output fg of the waveform shaping circuit 9 is input to the phase comparator 13, the output of the difference is passed through the low pass filter 14 only for low frequencies and is input to the voltage controlled oscillator 11, and is set by the time constant setting circuit 10. It is controlled so that it becomes the phase.

As described above, in the present embodiment, the print head motor 7 uses the speed phase comparator 4, the low-pass filter 5, the motor for the clock of the frequency fs obtained by dividing the clock fx generated by the reference oscillator 1 by the frequency divider 3. A print head motor 7 is rotated at a rotational speed in which both the speed and the phase are synchronized by a phase locked loop including a drive device 6, a print head motor 7, an encoder 8 and a waveform shaping circuit 9.

Further, if the output of the encoder 8 is used to adjust the phase of the print timing pulse of the frequency f ₀ , the resolution will be insufficient. Therefore, in order to increase the print position resolution, the time constant setting 10 and the voltage controlled oscillator 11 are used. A pulse obtained by multiplying the pulse fg of the encoder 8 by a phase lock loop composed of the frequency divider 12, the phase comparator 13, and the low-pass filter 14 is used.

Here, when the time constant setting circuit 10 changes the number of rotations of the print head motor 7 according to the speed information from the speed information generator 1, the voltage controlled oscillator 11 is located at the center of the lock range of the phase lock loop for generating the print timing pulse. It is for setting the free running frequency fc of.

FIG. 2 is a circuit diagram of the speed setting frequency divider 3 used in the present invention. A terminal for setting speed setting data D _{0 to} D _n-1 is connected to the 2 × multiplier 15, and this terminal is connected to this terminal. The reference frequency fx can be set to the predetermined frequency fs by inputting the speed information D _{0 to} D _n-1 .

FIG. 3 is a circuit diagram of the time constant setting circuit 10 used in the present invention. When the speed information D _{0 to} D _n-1 is input from each terminal, each switch S _{0 to} S _{n of the} analog switch 16 is input. _-1 closes,
As a result, the voltage is set by the resistors Rx, Rx / 2 ¹ , Rx / 2 ² , ... Rx / 2 ^n-1 connected to the switches S _{0 to} S _n-1 , respectively, and this output sets the voltage controlled oscillator. 11 outputs are changed.

Thus, the clock for controlling the rotation of the print head motor 7 is given from the frequency divider 3, and its frequency fs is Becomes However, M = D ₀・ 2 ⁰ + D ₁・ 2 ¹ ＋ ・ ・ ・ ・ ＋ D _n-1・ 2 ^n-1
(7 ・ 2). The rotation speed Nm of the print head motor 7 is Becomes However, P is the inner partial peripheral ratio of the phase lock loop of the print head motor 7, and Fg is the number of pulses per rotation of the encoder 8 [pulses / rev].

The frequency f ₀ of the print timing pulse is obtained by setting the pulse Fg (fg) of the encoder 8 to N by the phase lock loop including the time constant setting circuit 10, the voltage controlled oscillator 11, the frequency divider 12, the phase comparator 13, and the low pass filter 14. Since it is multiplied, f ₀ = Nm / 60 × Fg × N ... (7.4). Voltage controlled oscillator in this phase locked loop
The free running frequency fc of 11 must be adjusted to a value close to the frequency f _{0 due} to the characteristics of the phase lock loop, but in this embodiment, it is adjusted by the circuit shown in FIG.

Generally, fc is an external time constant RC of the voltage controlled oscillator 11.
Determined by

However, K is a constant of the voltage controlled oscillator 11, R is a resistance, and C is a capacitor capacity.

The value of the resistance R in the equation (7.5) is (7.1), (7.
2) and (7.3) Therefore, it is understood that the value must be changed by the value M based on the speed information.

In this embodiment, the resistance R is changed in the time constant setting circuit 10 shown in FIG. 3 by the speed information D _{0 to} D _n-1 to switch the resistance circuit that increases with an exponential function of 2 ⁿ to form a composite resistance. , Its resistance value R ' Becomes However, Rx is the basic resistance of the network. Then, by substituting the equation (7.2) into the equation (7.8), Becomes Substituting the resistance Rx of the equation (7.9) into R of the equation (7.6), Therefore, it can be seen that the resistance Rx of the time constant setting circuit in FIG. 3 is a constant irrelevant to M according to the speed information.

As described above, in this embodiment, the number of revolutions Nm of the print head motor and the frequency f ₀ of the print timing pulse can be simultaneously controlled by one speed information.

Although the time constants of the frequency divider 3 and the voltage controlled oscillator 11 are changed in this embodiment, the time constants of the low pass filters 5 and 14 in FIG. 1 can be switched. Further, in this embodiment, the print head motor 7 can be used for other motors such as a floppy disk spindle motor and a record player DD motor, and the encoder 8 can be replaced with a tacho generator. Furthermore, in the present embodiment, the free running frequency fc of the voltage controlled oscillator 11 is realized by changing the resistance. Similarly, the value of the capacitor C is set to an exponential function of 2 ⁿ like C, 2C and 4C. It can also be realized by increasing the number of times and switching.

EFFECTS OF THE INVENTION As is clear from the above description, the present invention includes means for generating a predetermined frequency based on the speed information from the speed information generator, and the difference between the predetermined frequency and the frequency proportional to the rotation speed of the motor It includes first control means for setting the motor to a speed that matches the speed information, and means for setting the phase of the frequency of the drive timing pulse based on the speed information, and is proportional to the set phase and the rotation speed of the motor. Since the second control means for matching the phase of the frequency is provided, it is possible to control so that the rotation phase of the motor for driving the first drive mechanism and the phase of the drive timing of the second drive mechanism are synchronized. Allows to obtain stable timing signal at the same time for any motor rotation speed.
In addition, since the speed and the phase can be controlled by the first control means and the second control means, it is possible to ensure the synchronization of the first and second drive mechanisms and to sequentially print by moving the print head, for example. In such cases, there is an effect of preventing print rubbing.

[Brief description of drawings]

FIG. 1 is a block diagram of a print controller for an ink jet printer according to an embodiment of the present invention, FIG. 2 is a block diagram of a speed setting frequency divider used in FIG. 1, and FIG. 3 is a time constant setting circuit. It is a circuit diagram. 1 ... reference oscillator, 2 ... speed information generator, 3 ... divider, 4 ... speed phase comparator, 5 ... low-pass filter,
6 ... Motor drive device, 7 ... Print head motor, 8 ...
Encoder, 9 waveform shaping circuit, 10 time constant setting circuit, 11 voltage control oscillator, 12 frequency divider, 13 phase comparator.

Claims (1)

[Claims] 1. A first drive mechanism is driven by the rotation of a motor and a second drive mechanism is driven in synchronization with the motor by a predetermined drive timing pulse, wherein the speed information is generated by a speed information generator. First control means for setting the motor to a speed that matches the speed information by a difference between the predetermined frequency and a frequency that is proportional to the rotation speed of the motor, and driving the motor based on the speed information. A drive control device for a two-system drive mechanism, comprising: a means for setting the phase of the frequency of the timing pulse; and a second control means for matching the set phase with the phase of the frequency proportional to the rotation speed of the motor.