JPH07245993A - Method of controlling motor - Google Patents

Abstract

PURPOSE:To lessen vibration and increase the speed accuracy by letting a driving curve have a constant speed condition or a speed converging condition just before the motor reaches a specified low speed. CONSTITUTION:An MPU 101 outputs from an output port 103 a signal for two-phase excitation which is required for driving a stepping motor 80. The timing when the output changes is controlled by the software of the MPU 101, that is, a start-up pulse frequency is about 100 pps and a frequency at a specified constant speed area is about 100 pps. At that time, a driving curve of a ramp-up is formed with an S-shaped curve which connects inflection points of a cubic curve to about 900 pps. Then, an about 2-5 constant-speed pulse is applied and thereby a linear driving curve is formed and the frequency is raised to a specified constant-speed frequency. By converging the speed to a constant speed just before a constant-speed frequency and raising the frequency to a specified constant-speed one in a few pulses, vibration due to the fructuation of the speed can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control system using a stepping motor as a drive source.

[0002]

2. Description of the Related Art Since stepping motors have excellent rotational positioning accuracy, they have been widely used as a drive source for industrial equipment in recent years. In particular, it is widely used as a driving motor for office equipment, so-called OA equipment.

The stepping motor is often used in a through area outside the self-starting area. Therefore, the engine is started up at a low rotation speed within the self-starting region and accelerated to a predetermined rotation speed. Then, in the case of stopping, the rotation speed is decelerated from the used rotation speed, and the rotation speed is lowered to a low rotation speed within the self-starting region to stop. The above driving method is generally used. The acceleration and deceleration curves of the time and the number of revolutions are linear type, exponential type, S
Characters and the like are often used because of their excellent torque characteristics and vibration characteristics. Further, in order to improve the vibration characteristics and the like in a limited configuration, for example, a control method of sending a pulse having a long time to deviate from the predetermined acceleration / deceleration curve during acceleration is used.

[0004]

However, in the conventional stepping motor drive system,
In some cases, it was not possible to suppress vibration sufficiently. Particularly, in the case of a recording apparatus in which a head is mounted on a carriage and printing is performed by scanning, unless the vibration is sufficiently suppressed, it has been a cause of deteriorating the printing quality.

[0005]

According to the present invention, a motor having a stepping motor drive circuit for exciting each phase and a control circuit for transferring data corresponding to a predetermined stepping motor drive curve to the drive circuit. In the control device, the drive curve once has a constant speed state or a converged state at a speed before reaching a predetermined constant speed.

Further, an S-shaped drive curve is formed from an initial speed of startup to a speed that is a constant speed or a convergence speed at a speed before reaching the predetermined constant speed. At a speed before reaching the predetermined constant speed, a constant speed state or a speed having a convergent state to a predetermined constant speed is formed by a linear drive curve.

At a speed before reaching the predetermined constant speed, a constant speed state or a speed having a convergent state is changed to a predetermined constant speed by the next drive pulse. In both the ramp-up and the ramp-down, a constant speed state or a converged state is temporarily set before or after the predetermined constant speed.

Further, in a recording apparatus having a carriage for scanning which has a recording head for forming an image on a recording medium, the carriage is scanned by using a stepping motor driven by the motor control method.

By the above means, it is possible to reduce the vibration of the motor or the like by driving the speed, so that the vibration during the scanning of the carriage can be reduced and the speed accuracy is improved, so that the printing quality can be improved. Becomes

[0010]

【Example】

(Embodiment 1) Embodiment 1 of the present invention will be described with reference to FIGS. A stepping motor is used as a drive source of a recording apparatus that mounts a head on a carriage and scans for printing. Recording device 1 having automatic paper feeder
Is a paper feed unit 2, a paper feed unit 3, a paper discharge unit 4, a carriage unit 5,
It is composed of a cleaning unit 6. Therefore, these are divided into items and the outline is described sequentially. 1 is a perspective view showing the overall configuration of the recording apparatus 1, FIG. 2 is a front view of the recording apparatus 1, and FIG. 3 is a sectional view of the configuration of the recording apparatus 1.

(Paper Feed Unit) In the paper feed unit 2, a pressure plate 21 on which the sheet material P is stacked and a feeding rotary member 22 for feeding the sheet material P.
Are attached to the base 20. A movable side guide 23 is movably provided on the pressure plate 21 to regulate the stacking position of the sheet material P. The pressure plate 21 is the base 20.
It is rotatable about a rotation shaft coupled to the feeding roller 22 and is urged toward the feeding rotating body 22 by a pressure plate spring 24. A separation pad 25 made of a material having a large friction coefficient, such as an artificial leather, which prevents double feeding of the sheet material P is provided at a position of the pressure plate 21 facing the feeding rotating body 22. Further, the base is provided with a separation claw 26 that covers a corner of the sheet material P in one direction and separates the recording sheets P one by one, and a separation claw 26 such as thick paper.
A bank portion integrally formed with the base 20 to separate the unusable items, the switching lever 28 for switching so that the separation claw 26 operates at the plain paper position and the separation claw 26 does not operate at the thick paper position, and the pressure plate 21. A release cam 29 for releasing the contact between the feeding rotating body 22 and the feeding rotating body 22 is provided.

In the above structure, the release cam 29 pushes down the pressure plate 21 to a predetermined position in the standby state. As a result, the contact between the pressure plate 21 and the feeding rotary body 22 is released. Then, in this state, the driving force of the conveying roller 36 is changed by the gear or the like to the feeding rotating body 22 and the release cam 29.
, The release cam 29 separates from the pressure plate 21, so that the pressure plate 21 rises, and the feeding rotating body 22 and the sheet material P are conveyed.
Contact each other, and the sheet material P is picked up and starts feeding with the rotation of the feeding rotating body 22, and is separated one by one by the separating claw 26 and sent to the sheet feeding unit 3. The paper feed rotator 22 and the release cam 29 rotate until the sheet material P is fed to the paper feed unit 3, and the contact state between the recording sheet P and the feed rotator 22 is released again, and the conveyance roller 36 is set. The driving force from is cut off.

(Paper Feeding Section) The paper feeding section 3 has a carrying roller 36 for carrying the sheet material P and a PE sensor 32. A pinch roller 37 that is driven is provided in contact with the transport roller 36. The pinch roller 37 is held by the pinch roller guide 30 and is urged by a pinch roller spring,
The pinch roller 37 is brought into pressure contact with the conveying roller 36 to generate a conveying force for the sheet material P. Further, an upper guide 33 and a platen 34 for guiding the sheet material P are arranged at the entrance of the sheet feeding unit 3 to which the sheet material P is conveyed. Further, the upper guide 33 uses PE for detecting the leading edge and the trailing edge of the sheet P.
A PE sensor lever 35 that communicates with the sensor 32 is provided. Further, a recording head 7 that forms an image based on image information is provided on the downstream side of the conveyance roller 36 in the recording sheet conveyance direction.

In the above structure, the sheet material P sent to the paper feeding section 3 is guided by the platen 34, the pinch roller guide 30 and the upper guide 33, and is sent to the roller pair of the conveying roller 36 and the pinch roller 37. At this time, the PE sensor lever 35 detects the leading edge of the conveyed sheet material P and thereby obtains the printing position of the sheet material P. Further, the sheet material P is a roller pair 3 by an LF motor (not shown).
When the plates 6 and 37 rotate, they are conveyed on the platen 34.

As the recording head 7, an easily replaceable ink jet recording head integrally formed with an ink tank is used. The recording head 7 can apply heat to the ink with a heater or the like. And
This heat causes the ink to film-boil, and the pressure change caused by the growth or contraction of the bubbles due to the film-boiling causes the ink to be ejected from the nozzles of the recording head to form an image on the sheet material P.

(Carriage Section) The carriage section 5 has a carriage 50 for mounting the recording head 7. The carriage 50 holds a guide shaft 81 for reciprocating scanning in a direction perpendicular to the conveyance direction of the sheet material P and a rear end of the carriage 50 to hold the recording head 7 and the sheet material P.
It is supported by a guide rail 82 that maintains a gap with the. In addition, these guide shaft 81 and guide rail 8
2 is attached to the chassis 8. The carriage 50 is driven by a carriage motor 80 attached to the chassis 8 via a timing belt 83. This timing belt 83 is used for the idle pulley 8
It is stretched and supported by 4. Further, the carriage 50 is provided with a flexible board 56 for transmitting a signal from the electric board 9 to the recording head 7.

In the above structure, when an image is formed on the sheet material P, the roller pairs 36 and 37 convey the sheet material P to the row position (the position in the conveying direction of the sheet material P) where the image should be formed, and the carriage motor. Carriage 50 by 80
Is moved to a column position (a position perpendicular to the sheet material P conveyance direction) for forming an image, and the recording head 7 is opposed to the image forming position. Then, the recording head 7 ejects ink toward the sheet material P in response to a signal from the electric substrate 9 to form an image.

(Paper Discharge Unit) In the paper discharge unit 4, the transmission roller 40
Comes into contact with the transport roller 36,
0 is provided in contact with the paper discharge roller 41. Therefore, the driving force of the transport roller 36 is transmitted to the paper discharge roller 41 via the transmission roller 40. In addition, the discharge roller 41
A spur 42 is in contact with the paper discharge roller 41 so as to be driven and rotatable. With the above configuration, the carriage unit 5
The sheet material P on which the image is formed is sandwiched in the nip between the paper discharge roller 41 and the spur 42, conveyed, and discharged to a paper discharge tray or the like (not shown).

(Cleaning Section) In the cleaning section 6, the driving force from the pump 60 for cleaning the recording head and the cap 61 and the conveying roller 36 for suppressing the drying of the recording head 7 is switched to the sheet feeding section 2 and the pump 60. It is composed of a drive switching arm 62. When the drive switching arm 62 is not feeding or cleaning, the planetary gear (not shown) that rotates around the axis of the transport roller 36 is fixed at a predetermined position, so that the drive unit 2 and the pump 60 are driven. No power is transmitted. Carriage 50
When the drive switching arm 62 is moved in the direction of arrow A by moving, the planetary gear becomes free, and accordingly, the planetary gear moves in accordance with the forward or reverse rotation of the transport roller 36, and the transport roller 36 normally rotates. At this time, the driving force is transmitted to the sheet feeding unit 2, and when the rotation is reversed, the driving force is transmitted to the pump 60.

Next, the drive system of the stepping motor of the present invention used to drive the carriage portion 15 will be described.

FIG. 4 is a block diagram showing the components of the present invention. In FIG. 4, reference numeral 101 denotes an MPU that performs motor drive control, 102 is a Pulse Width connected to the MPU bus, and its frequency and duty can be set.
is a modulator (hereinafter referred to as a PWM unit), 103 is an output port connected to the MPU bus, I / O port for generating a coded signal for driving a stepping motor, and 80 is a two-phase Unipolar stepping motor of
Is the stepping motor 8 by the I / O port output 103
2 shows a current control transistor that controls zero winding current.
Reference numeral 107 denotes a flywheel diode that forms a path for conducting current when the current control transistor 106 is turned off, and 108 denotes a programmable timer unit connected to the MPU bus of the MPU 101.

In the above structure, the MPU 101 generates signals from the output port 103 as shown in A, B, C and D of FIG. 5 for two-phase excitation required for driving the stepping motor 80. The timing at which the output changes is controlled and output by the software of the MPU 101 by the timer 109. The MPU 101 has a certain frequency in the PWM unit 102, for example, 20 Kz higher than the audible range of the human ear.
It is set to output a predetermined duty pulse for each excitation in the same manner as the table of the stepping motor drive of the motor drive at the above frequency. The output example is shown in E and F of FIG.

With this output, the current control transistor 10
6 is energized and supplies current to the stepping motor 80. The flywheel diode 10 when off
8 through which the electric power stored in the inductance of the winding of the stepping motor 80 is discharged, and by repeating this, a current having a value proportional to two output pulse duty is supplied to the selected winding of the stepping motor 80. It becomes possible to flush.

At this time, a drive curve diagram showing the speed of the stepping motor 80 is shown in FIG. The number of applied pulses in the through region of rising is about 25 to 50 pulses. The stepping motor 80 in this embodiment uses a 96-step PW type, the drive start pulse frequency is about 100 pps, and the frequency in the predetermined constant speed range is about 1000 ps.
ps. At this time, the ramp-up drive curve is formed by an S-shaped curve connecting the inflection points of the cubic curve up to about 900 pps.

Then, a constant speed pulse of about 2 to 5 is applied to form a linear drive curve with a pulse number of about 2 to 5, and the voltage is raised to a predetermined constant speed frequency of about 1000 pps. The ramp-down drive curve is almost symmetrical to the ramp-up drive curve. In this way, by converging to a constant speed once before the constant speed frequency and then setting the predetermined constant frequency within a few pulses from that, it becomes possible to reduce the vibration of the motor or the like due to the speed fluctuation.

By using the above stepping motor driving method, the vibration during the scanning of the carriage 5 can be reduced and the speed accuracy is improved, so that the printing quality can be improved. Further, since a short start-up area is sufficient, the printing time can be shortened and the device size can be reduced.

(Embodiment 2) In Embodiment 1, the ramp-up drive curve is formed by an S-shaped curve connecting inflection points of the cubic curve up to about 900 pps, and a constant speed pulse of about 2 to 5 is applied. , A linear drive curve was formed with a pulse number of about 2 to 5, and the pulse was started up to a predetermined constant speed frequency of about 1000 pps. Regarding the ramp-down drive curve, we added a symmetrical shape to the ramp-up drive curve, but instead of the S-shaped curve that connects the inflection points of the cubic curve, FIG.
A linear drive curve may be used as shown in FIG. Further, the ramp-down drive curve may be asymmetric with the ramp-up drive curve, and may be raised with a linear drive curve from the constant speed frequency of 1000 pps to 100 pps.

By using the above drive curve, it is possible to increase the conditions of the drive curve that can further reduce the vibration, and it becomes easy to deal with a slight change in the mechanical carriage structure. Therefore, it goes without saying that the drive curve may have an exponential curve, a parabolic curve, a sine curve, etc. other than the linear type. Other configurations are similar to those of the first embodiment.

(Embodiment 3) In Embodiment 1, the ramp-up drive curve forms an S-shaped curve connecting inflection points of the cubic curve up to about 900 pps, and a constant speed pulse of about 2 to 5 is formed. Was applied to form a linear drive curve with a pulse number of about 2 to 5, and the voltage was raised to a predetermined constant speed frequency of about 1000 pps. However, as shown in FIG. It is also possible to raise the constant speed frequency to about 1000 pps by the next pulse without applying the voltage.

By using the above drive curve, it is possible to increase the conditions of the drive curve that can further reduce the vibration, and it becomes easy to deal with a slight change in the mechanical carriage structure. Other configurations are the same as those of the first embodiment.
Is the same as.

[0031]

According to the present invention, it is possible to reduce the vibration of the motor or the like due to the speed fluctuation, so that the vibration during the scanning of the carriage can be reduced and the speed accuracy is improved, so that the printing quality is improved. It becomes possible. Further, since the startup is short, the printing time can be shortened and the device size can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall configuration of a recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a front view of the recording apparatus according to the first embodiment of the present invention.

FIG. 3 is a configuration cross-sectional view of a recording apparatus according to the first embodiment of the present invention.

FIG. 4 is a block diagram of a stepping motor drive device according to the first embodiment of the present invention.

FIG. 5 is a time chart of the stepping motor drive recording apparatus according to the first embodiment of the present invention.

FIG. 6 is a stepping motor drive curve diagram in the first embodiment of the present invention.

FIG. 7 is a stepping motor drive curve diagram in the second embodiment of the present invention.

FIG. 8 is a stepping motor drive curve diagram in the third embodiment of the present invention.

[Explanation of symbols]

 1 Recording Device 2 Paper Feeding Section 3 Paper Feeding Section 4 Paper Discharging Section 5 Carriage Section 6 Cleaning Section 7 Recording Head 8 Chassis 9 Electric Board 36 Conveying Roller 37 Pinch Roller 50 Carriage 56 Flexible Board 80 Carriage Motor 81 Guide Shaft 82 Guide Rail 83 Timing belt 84 Idle pulley 101 MPU 102 PWM unit 106 Current control transistor 107 Flywheel diode 108 Timer unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Kinoshita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tan Attoming 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Makoto Karama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masahiro Taniguro 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. In-house (72) Inventor Tetsuo Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Koichi Tanno 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. A motor control device having a stepping motor drive circuit for exciting each phase and a control circuit for transferring data corresponding to a predetermined stepping motor drive curve to the drive circuit, wherein the drive curve is predetermined. A motor control method characterized by having a constant speed state or a convergence state once at a speed before reaching a constant speed. 2. The motor control method according to claim 1, wherein an S-shaped drive is performed from an initial start-up speed to a speed that is a constant speed state or a convergence state at a speed before reaching the predetermined constant speed speed. A motor control method characterized by being formed by a curve. 3. The motor control system according to claim 1, wherein a linear drive curve is provided from a speed that is once in a constant speed state or converges at a speed before reaching the predetermined constant speed to a predetermined constant speed. A motor control method characterized by being formed by. 4. The motor control method according to claim 1, wherein the speed is a constant speed at a speed before reaching the predetermined constant speed, or a speed having a convergent state is changed to a predetermined constant speed by the next drive pulse. A motor control method characterized by: 5. A motor control method characterized by having a constant speed state or a convergence state once before or after a predetermined constant speed in both ramp-up and ramp-down. 6. A printing apparatus having a carriage for scanning and having a print head for forming an image on a print medium, using a stepping motor driven by the motor control method according to claim 1. A recording device for scanning the carriage.