JPH02266967A - Paper feed motor speed regulation method - Google Patents

Abstract

PURPOSE:To enable measuring a speed excepting the speed variation component for one rotation period of a rotor and to make the phase adjustment of a sensor easy and accurate by setting a period required for measuring a speed to the period of time for an integer of rotations of a motor rotating at a target speed. CONSTITUTION:The body of a paper feed pulse motor 1 is provided with a sensor 4 capable of detecting the position of the slit 21 of an encoder 2 so that said sensor can move circumferentially of said motor. When the phase of said pulse motor is changed in the period of time t0 after generation of the output signal of said encoder 2, the pulse motor 1 rotates at a speed according to a phase difference between the encoder 2 and a stator. Said encoder 2 and stator and a rotor have a dimensional tolerance to generate a speed variation making one rotation of said rotor its period. However, when a period required for measuring a speed is set to an integer of times of the period of time for one rotation of the pulse motor rotating at a target speed, an errorless measurement is possible even if the measurement starts from any place.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is applicable to printing devices such as line printers, etc.
This invention relates to a motor speed adjustment method when driving a pulse motor in a closed loop.

[Background of the invention]

In such a printing device, the pulse motor is: (1) easy to control; and (2) low cost. ■Because of its high positioning accuracy, it is used in many areas such as paper feeding and print head feeding. One of the pulse motor control methods is closed loop drive using an encoder. This is a method in which an encoder that generates one signal per motor step is connected to the motor shaft, and phase switching is performed based on the encoder signal. Features of closed-loop control: ■It is difficult to step out, so the motor can be driven at high speed and high torque. ■It has the advantage of being able to detect step-out, and is used for paper feed drives in high-speed line printers. In closed-loop control, the phase of the encoder and stator rotation direction is initially determined! l
io! It is necessary to generate an encoder signal when the rotor and stator are in a predetermined positional relationship.

This is to prevent a phase difference from appearing as a speed difference even if the motors are driven using the same closed-loop speed control.

One of the methods for initially adjusting the phase is a speed adjustment method. This is a method in which the motor is driven under a certain closed-loop control, and the position of the encoder is set so that the motor rotates at a predetermined speed. To explain this more specifically, the quality of the adjustment is determined depending on whether a predetermined number (ΔN) of encoder signals are generated within a certain fixed time (ΔT). Here, in the past, the value of ΔT was selected without regard to the period of one rotation of the rotor, so there was a problem that the measured value (ΔN) was different every time the measurement was performed.

FIG. 2 specifically shows this. As shown in the figure, due to dimensional tolerances of the motor 1 and encoder 2, there is a speed fluctuation with a cycle of one rotation of the rotor. Here, if the measurement time ΔT is set to the time equivalent to half a revolution of the rotor as shown in Figure 2, then when measuring a slow half revolution as in Example 2, the measured value ΔN
When measuring a fast half-circle as in Example 1, many measured values ΔN will be detected, and the true value will not be obtained.The value of ΔN will change each time it is measured, and it will be adjusted to the adjustment target value ΔNo. (Objective of the Invention) The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to facilitate initial encoder phase adjustment when driving a pulse motor using closed loop control. There is a particular thing.

[Summary of the invention]

The present invention focuses on the fact that the motor speed fluctuation corresponds to the period of one rotation of the rotor, and sets the speed measurement time to an integral multiple of the period of one rotation of the rotor so as to suppress variations in the measurement results for each measurement.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIGS. 1 and 3.

In FIG. 3, a pulley 3 is fixed to one output shaft of a pulse motor 1 for paper feeding, and an encoder 2 is fixed to the other output shaft. A sensor 4 capable of detecting the position of the slit 9821 of the encoder 2 is attached to the body of the pulse motor 1 so as to be movable in the circumferential direction of the motor. The pulley 3 is connected to a pair of tractors (not shown) via a timing belt, a pulley, a drive shaft, etc. (not shown), and when the pulse motor 1 operates, printing paper loaded in the tractor can be fed.

Further, the output of the encoder 2 is input to a controller and a motor driver (not shown), and the motor is driven at the timing shown in FIG.

In such a paper feed drive device, when the phase of the pulse motor is switched after the output signal of the encoder 2 is generated as shown in FIG. 4, the pulse motor 1 rotates at a speed according to the phase difference between the encoder 2 and the stator. .

Since the encoder 2, stator, and rotor have dimensional tolerances, as shown in FIG. 1, speed fluctuations occur with a cycle of one rotation of the rotor.

However, as shown in Figure 1, if the speed measurement period is set to an integral multiple of the time for one revolution of the pulse motor rotating at the target speed, no matter where the measurement starts, it will be measured without error as in Examples 1 and 2. can.

〔Effect of the invention〕

According to the present invention, since the measurement time of speed measurement is set to the time required for an integer number of revolutions of the motor rotating at the target speed, speed measurement can be performed excluding the speed fluctuation component of one rotation period of the rotor, and the phase adjustment of the sensor is easy. Be accurate.

[Brief explanation of drawings]

Fig. 1 is a timing diagram showing the speed adjustment method according to the present invention, Fig. 2 is a timing diagram showing the conventional speed adjustment method, and Figs. 3 and 4 show the paper feed drive section of the printer and the closed loop control method. 2 is a perspective view and a timing chart shown in FIG. In the figure, 1 is a pulse motor, 2 is an encoder, 3 is a pulley, 4 is a sensor, and 21 is a slit. Name of patent applicant Hitachi Koki Co., Ltd.

Claims (1)

[Claims] A pulse motor, an encoder fixed to the output shaft of the pulse motor and having the same number of slits as the number of steps per revolution of the pulse motor, and the encoder fixed to the body of the pulse motor in a circumferential direction so that its mounting position can be adjusted. In a paper feed drive device consisting of a sensor that detects a slit and a driver that receives the output of an encoder and switches the phase of the pulse motor after a certain delay time, the sensor When adjusting the position of the paper feed motor, the paper feed motor speed adjustment method is characterized in that, when adjusting the position of the pulse motor, the number of encoder signals generated per integer number of rotations of the pulse motor rotating at the predetermined rotation speed is counted, and the speed is adjusted based on the number of generated encoder signals. .