JPS63302798A - Feed control system in stepping motor - Google Patents

Abstract

PURPOSE:To improve the feed precision with space between a latter on the first line and a letter on the second line after power is turned ON, by correcting the difference of rotor stop positions with a self-starting frequency added by a micro step in initial operation such as in putting the power supply to work. CONSTITUTION:The power supply LFON to an LF motor 1 (stepping motor) of a device is put to work and a self-starting frequency LFCLOCK is supplied, with which the LF motor 1 is at first rotated by three steps counterclockwise (in CCW operation) and then rotated by three steps clockwise (in CW operation). It is operated when the exciting coils are energized which are adjacent each other in steps where the exciting phases phi1-phi4 of exciting current flowing through the LF motor 1 is in phi41-phi34-phi23 and then phi34-phi41-phi12 and the rotor stop position in nonconduction and that in conduction are caused to coinscide in a position P0.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to drive control of a paper feeding stepping motor in a serial printer or the like.

(Prior Art) Conventionally, drive control of a paper feed stepping motor (hereinafter referred to as an LF motor) of a serial printer, etc. is performed.

This was done using its self-starting frequency. For this reason, if you try to increase the printing speed of the printer, you need to increase the paper feed speed, so there is a limit to the use of a low-torque LF motor, and a high-torque LF motor has to be used, which is expensive. There was a drawback.

In addition, the LF motor supplies a constant minute holding current to the excitation coil even when the drive is stopped, and controls it so that it does not rotate due to external force. There is a method in which the rotor is always aligned with the stop position of the rotor (during driving) to ensure accurate feeding of one sheet, and a method in which the holding current as described above is not supplied.

In the case of the above-mentioned holding current supply method, when the operator wants to adjust the paper feeding position for some reason, the platen friction torque and the torque due to the holding current of the LF motor are added (approximately 5 kg), and the operator manually adjusts the position. It has the disadvantage that it is difficult to remove, and it is also uneconomical in terms of power consumption.

Therefore, in view of this point, recently, the latter method in which no holding current is supplied has been adopted. LF using this method
Motor drive control depends on the self-starting frequency mentioned above.
Because it does not supply holding current.

There is a difference in the rotor stop position when the power is not applied and when it is energized (motor step-out), and as a result, there is a deviation in the printing line, which has the disadvantage that normal printing cannot be performed.

(Problems to be Solved by the Invention) As mentioned above, the method of always supplying a minute holding current to the LF motor and the method of not supplying it have contradictory drawbacks. LF not supplied
When employing motor drive control, there has been a problem that the rotor stop position must be corrected and the paper feeding may become inaccurate unless this is done accurately.

(Object of the Invention) Therefore, in drive control of an LF motor that does not supply a holding current, the present invention starts the LF motor after making the rotor stop position when not energized coincide with the rotor stop position when energized. In addition to improving the paper feeding accuracy between the first and second line characters, when the rotor stop positions are different, the self-starting frequency is supplied for at least two steps or more, and the start-up and escape of the LF motor during through-up is improved. The purpose of this is to prevent startup errors by preventing overloading, and to realize this with a low-cost LF motor.

(Structure and operation) In order to achieve the above-mentioned object, the present invention rotates the stepping motor at a self-starting frequency and then performs high-speed rotation by through-up. The self-starting frequency is added in small steps during initial operation, and the stepping motor is rotated by the same step clockwise or counterclockwise to compensate for the difference between the rotor stop position when the motor is not energized and the rotor stop position when the motor is energized. It is characterized by the fact that

The basic operation of the present invention will be explained with reference to FIGS. 1 to 5. FIG. 1 shows an operation control timing chart for paper feeding, where LF turns on the stepping motor (LF motor), that is, turns on the paper feeding power of the device.

LFCLO or LF motor self-starting frequency, φ1 to φ,
indicates the excitation phase (four-phase excitation) of the excitation current supplied to the excitation coil of the LF motor, and SM indicates the operating state in the rotational direction for the excitation phases φ1 to φ of the LF motor.

In the initial state when power is applied to the LF motor, the rotor stop position when no electricity is applied is made to match the rotor stop position when electricity is applied.

Now turn on the power of the LF motor of the device (LFOII) L/.

Supply the self-starting frequency (LF (IL...a), and first take 3 steps in the counterclockwise direction (caw operation), then take 3 steps in the clockwise direction (CW operation). At this time, the current flowing to the LF motor The excitation phase φ, ~φ, of the exciting current is φ41-φ34-φ211, then φ34-φ4゜-φ1, as shown in the figure.
Steps 2 and 3 operate when the excitation coils adjacent to each other are energized (indicated by the thick line SM), and the rotor stop position when not energized matches the rotor stop position when energized at the P0 position (black circle mark).

During these operating processes, the LF motor stops at point A1 and A2 in FIG. 2, and point 81 in FIG. 3.

Existing at 83 points, C1 point in Fig. 4, and 62 points, excitation phase φ1
~φ, may be related as shown in the figure. The diagonal line in the center of each rotation indicates the load torque of the LF motor, (+) indicates positive rotation to the right (clockwise direction), and (-) indicates negative rotation to the left (counterclockwise direction).

Now, in Fig. 2, when the rotor stop position of the LF motor when no power is applied is at point A1 or point A3, and when the self-starting frequency is applied to the LFON (Fig. 1) for paper feeding operation,
Since the φ1□ phase before excitation phase switching has higher power than the load torque (shaded area), the rotor at the P0 position stops. In this case, when the rotor stops at point A1, it rotates clockwise, and when it stops at point A2, it rotates counterclockwise. Next, the excitation phase is switched, and φ2. Phase → φ34 Phase → φ, 1 phase → φ1. phase···
. . ., the LF motor is started, gradually slews up, and rotates at high speed.

In Fig. 3, the rotor stop position of the LF motor when no current is applied is at the 81st or 83rd point, and the φ before excitation phase switching is
Even if the 2nd phase is energized with high power, the load torque does not exceed the load torque (diagonal line) and does not start, then φ2. Due to the excitation of the phase, the load torque exceeds the load torque and rotates counterclockwise, and then φ1. Rotates clockwise due to phase excitation.

Sequentially φ,, Phase → φ1□ Phase → φ2. By switching the phase... and the excitation phase, clockwise rotation operation is started.

In Figure 4, when the rotor stop position of the LF motor is at point 01 or 02' when no current is applied, it is basically the same as the case at point A1 or point A2 in Figure 2, but C The activation starting point at point □ is the position P-1, and that at point 02 is the position P, and so on.

In this way, as can be seen from the explanations in FIGS. 2 to 4, the rotor stop position of the LF motor is point A.

Regardless of whether it is at point B or point 0, the self-starting frequency is set to normally start starting from at least the second pulse (excitation phase φ).

FIG. 5 is a paper feed operation control timing chart showing the normal operation in detail. The same symbols as in Figure 1 indicate the same functions; the self-starting frequency (L F cLocK) continues for three steps, and then the LF
The motor is shown rotating at high speed. LF motor (
Before switching the phase of the excitation current for SM), the above-mentioned starting point correction (LF motor rotor stop position) is performed, and in two steps after switching, the start-up correction is performed, through-up is performed, and... through-through is performed. After going down, it becomes stationary and stable. By performing such control, the deviation of the rotor stop position when the paper feeding operation is started is corrected.

Regarding the handling of the LF motor that is subject to start-up control as described above, the paper feed operation switch is turned off, the LF motor is de-energized with one paper feed inactive, and the operator operates the platen. If not, the rotor stop position at that time and the rotor stop position when energized match,
No problem occurs, but if the operator performs manual operation for some reason, the same thing will occur as when the power is turned off. In such a case, when the paper is fed, the rotors are brought into a state where the rotors stop at the same position by first taking two or more steps counterclockwise (rotating to the left) and then taking two steps clockwise (rotating to the right).

In addition, in order to operate the LF motor at high speed without the operator being able to detect and correct the rotor stop position after de-energization, if the through-up operation is performed immediately after de-energization, point B2 in Fig. 3 mentioned above, At the 82 point position,
The actual activation is the second pulse excitation phase φ3. This is due to the excitation from . In other words, if the normal through-up is performed immediately after supplying the self-starting frequency, the LF motor will not be able to start normally due to the shift in the rotor stop position, resulting in a step-out phenomenon, which is undesirable.In this case, at least φ as shown
23 phases, φ3. It is necessary to start up to two steps of the phase at the self-starting frequency. This can prevent line misalignment between the first and second line characters.

(Embodiment) Fig. 6 shows a configuration diagram of an embodiment of the present invention, in which 1 is an LF motor (stepping motor), which is a drive source for a paper feeding mechanism and drives excitation coils 11 to 14 of four phases φ1 to φ. have 2 is a microcomputer, which is equipped with a reference oscillator 21 and performs the paper feed operation (LFON) detailed in FIGS. 1 to 5 above.
- Self-starting frequency (LFcLocx) - Controls the supply of excitation phases φ, ~φ, 9 to the excitation coil, etc. 3 is a drive for the LF motor 1, which is composed of a power transistor F and the like.

In the operation of this embodiment, the drive control of the LF motor 1 described above is performed by the microcomputer 2, and the rotor stop position when no electricity is applied is corrected to match the one rotor stop position when electricity is applied, and the through-up is performed to increase the speed. It is something that is rotated.

FIG. 7 is a flowchart illustrating the functions of the microcomputer 2 for controlling the LF motor drive in FIG. 6, which is processed based on the operations shown in FIGS. 1 to 5. That is, (A) in the figure is an initialization routine, (B) is a routine for receiving an LF motor drive request and generating an excitation phase switching time management interrupt, and (C) is a routine for generating an excitation phase switching time management interrupt after starting the LF motor. This shows the routine for acceleration (through-up), constant speed, and deceleration (through-down).

(Effects of the Invention) As explained above, according to the present invention, the rotor stop position when the power is turned off and the rotor stop position when the power is energized are made to match by adding a self-starting frequency of at least two steps or more. be able to. Therefore, the accuracy of paper feeding between the characters on the first line and the characters on the second line after power-on can be significantly improved.

In addition, it is possible to start the through-up even after no power is applied.
High-speed control of the paper feed motor becomes possible.

[Brief explanation of the drawing]

Fig. 1 is an operation timing chart of the paper feed control of the present invention, Figs. 2 to 4 are explanatory diagrams of the motor stop position and excitation phase switching when no electricity is applied, and Fig. 5 is a detailed timing chart of Fig. 1. , FIG. 6 is a block diagram of an embodiment of the present invention, and FIG. 7 is a flowchart of FIG. 6. LFol...Paper feed power turned on. Ll4゜Ll... Self-starting frequency, φ1~φ,... Excitation phase of exciting current, SM... Operating status of stepping motor. 1...Stepping motor (LF motor), 2...
microcomputer. 3... Driver. Patent applicant Ricoh Co., Ltd. - Figure 1 Figure 5 Figure 6 1... LF motor 2... 74 Kurofunhi 11ta 3° LF Mormorph 4 bar ■...Engraving 1 1 and 21 ...Stem? Figure 7 (A) of the sword phase! Laken (to the start) Figure 7 (C) Makoto, friend, late - Ken procedural amendment (1st edition August 18, 1985 2, title of invention Stepping motor paper feed control method 3, amendment) Relationship with the case involving the person who filed the patent application Address: 1-3-6 Nakamagome, Ota-ku, Tokyo Name (674) Ricoh Co., Ltd. Representative
Hama 1) Hiro 4, Agent 5, Number of inventions increased by amendment 06, Target of amendment Drawing 7, Contents of amendment Fig. 6 will be amended as shown in the attached sheet. that's all

Claims (2)

[Claims] (1) Rotate the stepping motor at a self-starting frequency,
Next, in paper feed control of the stepping motor that rotates at high speed by through-up, the self-starting frequency is added in small steps at the initial operation such as when the device is powered on, and the stepping motor is rotated by the same step in the clockwise or counterclockwise direction. A paper feed control method for a stepping motor, characterized in that the difference between the rotor stop position when no electricity is applied and the rotor stop position when electricity is applied is corrected by rotating the motor. (2) The stepping motor according to claim (1), characterized in that when the stepping motor is used with a through-up to a self-starting frequency or higher, the through-up is performed after adding at least two or more steps of the self-starting frequency. Motor paper feed control method.