JP2000188894A - Method for controlling acceleration of motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly accelerate a motor and, at the same time, to reduce the overshooting of the motor after the rotating speed of the motor reaches a target speed, by issuing an order so that the acceleration change of an object to be controlled may become continuous and smooth or the differential change of the acceleration may become continuous in accelerating a mechatronic device which uses the motor as its driving source. SOLUTION: In the acceleration graph, the peak of an intermediate acceleration is large as compared with the position (4), but it can be said that the acceleration continuously changes, because the acceleration gradually increases after the acceleration is started and gradually returns to '0' after the acceleration is completed. Since the driving force which makes the acceleration trace this speed variation curve continuously changes the acceleration as shown by curve (2), an object to be controlled can be controlled in a more natural low-loss state. In addition, when a 'speed command value' is given by the quintic functional speed variation curve (1), led to a target speed of 600 mm/sec, and simulated, the spot where the speed changes in steps during acceleration becomes smoother and the overshooting of a motor also becomes smaller after the rotating speed of the motor reaches the target value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the acceleration of a motor drive of any device such as a serial type ink jet printer and a scanner.

[0002]

2. Description of the Related Art Conventional acceleration control using a motor will be described with reference to an example of carriage scanning drive of a serial type ink jet printer recording apparatus.

FIG. 2 illustrates a carriage driving mechanism using a DC motor. The scanning drive (arrows A and B) of the carriage 151 on which the recording head is mounted is performed by a DC motor 152 fixed to a chassis (not shown) of the recording apparatus. A driving pulley 153 is connected to the motor shaft, a toothed rubber belt 155 is stretched between the driving pulley 153 and the idler pulley 154 provided on the opposite side of the scanning range of the carriage 151, and a rubber belt Is fixed, and the rotational motion of the motor is regarded as the rotational operation of the belt, which is converted into the scan operation of the carriage.

The idler pulley 154 is attached to a pulley holder (not shown), and is given a force by a belt tension spring (not shown) in a direction opposite to the motor (arrow C) to apply tension to the rubber belt. . Further, the pulley holder may be fixed to the chassis.

Reference numeral 156 denotes a linear encoder scale, for example, 360 lpi (line per inch, 25.
By detecting marks provided at regular intervals (4 mm / 360 = 70.6 μm) with the encoder sensor 157 fixed to the carriage 151, the position of the carriage 151 can be accurately acquired. An optical system or a magnetic system is used as the encoder system. Also, the carriage 1
At the time of scanning of 51, the speed of the carriage can be calculated from the time interval of continuous detection of marks on the linear encoder scale.

FIG. 3 is a schematic diagram illustrating a carriage scanning speed control system of a conventional serial type ink jet printer. The DC motor is controlled by a method called PID control or classic control. The procedure will be described.

First, a target speed to be given to the carriage 151 is given in the form of a "speed command". The "speed command" is a form in which a target speed is given from the beginning at a constant value as shown in (a), or is increased at a fixed rate as shown in (b).
A form that leads to a target speed is common.

The speed conversion circuit calculates the current “scanning speed” of the carriage from the signal of the encoder sensor and a clock built in the printer. The value obtained by subtracting the "scan speed value" from the "speed command value" is passed to the "PID arithmetic circuit" as a "speed error" that is insufficient with respect to the target speed, and the energy to be given to the DC motor at that time is represented by " It is calculated by a method called “PID calculation”. In this example, the “motor driver circuit” that has received the signal sets the motor applied voltage constant, and changes the pulse width of the applied voltage (hereinafter referred to as “PWM (Pulse Widget)”.
h Modulation) control), by changing the duty of the applied voltage, adjusting the current value, adjusting the energy applied to the DC motor, and controlling the speed.

[0009]

In recent years, the image quality of a color ink jet recording apparatus has been remarkably advanced, and a higher image quality called "photographic image quality" has been required. The demand for higher resolution for higher image quality has also increased, and what has been about 360 dpi several years ago and now has a resolution of 1440 dpi has been commercialized.

The spacing between adjacent dots, which was 70.6 μm at a resolution of 360 dpi, is now 17.000 at 1440 dpi.
In an ink jet recording system in which ink droplets of different colors are ejected into a predetermined area to express a color, the performance required for the landing accuracy is “micron order”, as small as 6 μm (= 25.4 mm / 1440). Up to.

In the ink jet recording system, it is necessary to make the fluctuation of the scanning speed of the recording head as close to zero as possible in order to maximize the accuracy of the ink droplet landing position. This is because the speed of the carriage when the ink droplet is ejected determines the ink droplet flight path and affects the landing position.

In particular, immediately after the start of the scanning, the speed fluctuation does not converge even immediately after the predetermined scanning speed is reached, so that the ink droplet landing accuracy at the end of the recording paper is reduced, and the improvement in print quality is hindered. Was inconvenient.

FIG. 4 is a graph given as an example. This graph is the result of simulation with MatLab / Simulink of Cybernet Systems, Inc. The vertical axis is speed, the horizontal axis is elapsed time,
From time 0 sec, a constant speed command value has been input, and the solid line indicates a change in the scanning speed of the carriage. In this example, the "speed command" is a method of giving a target speed of 600 mm / sec as a constant value from the beginning. It can be seen that the speed oscillates after reaching the target speed of 600 m / sec.

[0014] In order to suppress the speed fluctuation due to disturbance after converging to the target speed, it is necessary to increase the gain of the PID operation circuit as much as possible within a range not to impair the stability of the system. However, in the method of giving the speed command at a constant value as described above, if the gain is excessively increased, the acceleration is performed at an unnecessarily large acceleration, and the overshoot after reaching the target speed (called overshoot) becomes unnecessarily large. ,
Oscillating speed changes occur after overshoot,
The change in speed in the acceleration region is large, which is inconvenient considering the ink landing accuracy at that location.

In recent ink jet printers, the ink tank is generally mounted on a carriage. To improve image quality, Bk (black), Y (yellow), and M (color) have been conventionally required for color printing. (Magenta), C (cyan)) In addition to the four inks, L
More and more models are equipped with M (light magenta) and LC (light cyan) inks. In addition, in order to reduce the cost of the ink tank per print, the capacity of the ink tank is gradually increasing. As a result, the weight of the carriage increases, and when an unnecessary acceleration is applied, the carriage reacts to the unnecessary acceleration, and the entire apparatus vibrates or generates noise, which is inconvenient.

An area in which the carriage can scan at a constant speed for printing is called a constant speed area, and an area in which a distance required for acceleration is taken in front of the area is called an acceleration / deceleration area. Simply, if the acceleration / deceleration region is made sufficiently long, the acceleration can be made small, and printing can be started after the scanning speed is sufficiently stabilized, but there are strict requirements. This is because increasing the acceleration area in a serial printer directly leads to an increase in the overall width of the printer. In recent years, in which all apparatuses are in the direction of downsizing, it is inconvenient to increase the acceleration / deceleration area and increase the size of the apparatus even though it is for improving print quality, reducing noise and vibration.

Next, FIG. 5 shows a result obtained by simulating with MarLab / Simulink by a method of increasing the "speed command value" at a constant rate to reach the target speed of 600 mm / sec. (Parameters other than the speed command are the same as in FIG. 4.) The rate of increase in the speed command value is 0.0666 sec × 600 mm / secｓｅ2 = 20 m, as can be seen from the following equation.
m Target speed (600 mm / sec) at a scanning distance of 20 mm
Is set to reach. A broken line in the graph is a speed command, and a solid line is a change in the scanning speed of the carriage. In this case, control is performed so that the scanning speed of the carriage traces the inclination of the speed command, so that the carriage is not accelerated faster than necessary. However, as can be seen from the graph, during the acceleration, there is a stepped portion where the scanning speed exceeds the speed command and the speed slightly decreases. In such a case, the smoothness of the acceleration is impaired, which also causes an oscillating speed fluctuation, which is inconvenient.

The carriage scan drive of the BJP4000 series ink jet printer manufactured by the applicant is an open control using a PM motor. However, in order to realize smooth acceleration, a cubic function is added to the acceleration table. A curve has been applied. This concept will be described by applying it to control using a DC motor as a drive source. The basis of this idea is that instead of increasing the speed command value at a fixed rate, the increase is gradually increased, and the peak of the increase is obtained at the middle point of acceleration, and from there, The speed is gradually decreased, and when the target speed is reached, the increment of the speed is set to 0, so that acceleration start and acceleration completion are smoothed.

FIG. 6 shows the result obtained by simulating MatLat / Simulink by giving the "speed command value" as a cubic function curve and leading to the target speed of 600 mm / sec as described above. The parameters other than the speed command are the same as in FIG. In FIG. 5, the portion where the speed change shows a stepped shape during acceleration is somewhat smoothed and improved, but not enough.

Next, a method of obtaining a cubic speed change command curve will be described. For example, assume the conditions as follows. (A) The initial speed is 0 mm / sec. (B) Acceleration is completed by scanning 20 mm. (C) The target speed is 600 mm / sec. (D) The acceleration at the start of acceleration and at the completion of acceleration is zero.

If the velocity (v) is a cubic function of the time (t) and v = at ³ + bt ² + ct + d, then from the condition (a), t = 0 and v = 0, and therefore d
= 0 Acceleration (α) is a derivative of velocity, so α = v ′ = 3at ² + 2bt + c From condition (d), α = 0 at t = 0 from condition (d). Therefore, c = 0 acceleration completion time is set to t ₁ . From condition (d), t = t ₁
And α = 0. Therefore, 0 = 3 at ₁ ² +2 bt ₁ ... From the condition (c), t = t ₁ and v = 600. ^{_{Thus, 600 = at 1 3 + bt}} 1 2 ······ scanning distance (x) is because it is the integral of velocity (v), x = ∫vdt = (a / 4) t 4 + (b / 3 ) T ^{3 From} condition (b), t = t ¹ and x = 20. Thus, 20 = (a / 4) t 1 4 + (b / 3) t 1 3 When solving the ...... ,, formula is _{simultaneous, t 1 = 1/15,} a = -4050000, b = 4050000.

FIG. 7 is a schematic graph showing changes in the scanning distance (x), speed (v), and acceleration (α) represented by the equation of the cubic speed command curve obtained as described above. .
Considering these, indeed, if you look at the speed graph, compared to the method of increasing the speed at a fixed rate, the speed gradually increases at the start of acceleration, and smoothly near the completion of acceleration, continuously to the target speed. ing.

However, in the graph of the acceleration, the acceleration rapidly increases from 0 at the start of the acceleration, and rapidly returns to 0 at the completion of the acceleration. As is well known, F
Since (driving force) = M (mass) × α (acceleration), 3
If a speed function curve having a linear function is given, it is required to give a driving force as shown in the acceleration graph of FIG. In other words, the driving force changes discontinuously at the start of acceleration and at the completion of acceleration, and as a result, the smoothness of acceleration is impaired and the overshoot after reaching the target speed is increased. It is considered inconvenient.

Accordingly, it is an object of the present invention to provide a motor acceleration control method capable of smoothly performing acceleration and reducing overshoot after reaching a target speed.

[0025]

In order to achieve the above object, according to the present invention, as a method of controlling the operating speed at the time of accelerating the carriage, in a closed loop control using a DC motor or the like, a "speed command curve" is expressed by: In an open loop control using a pulse motor or the like, an “acceleration table” is typically given by a quintic function curve described in detail below.
The driving force generated by the driving source at the time of acceleration changes from “0” to “continuously and smoothly”.

In the carriage speed control of the present invention configured as described above, since the change in force for realizing acceleration is "continuous and smooth", acceleration control with little loss is possible.・ Vibration and noise during acceleration can be suppressed. -Vibratory speed fluctuations during acceleration are suppressed, contributing to improved ink landing accuracy and improved print quality. -Speeding up convergence of speed fluctuations during acceleration contributes to shortening of the acceleration region, so that the device can be downsized. The PID gain in the acceleration region can be set sufficiently high, which also contributes to speed convergence of speed fluctuation. Such an effect can be obtained.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a serial ink jet recording apparatus according to a first embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 8 is an external perspective view of the ink jet recording apparatus according to the first embodiment of the present invention, and FIG. 9 is a transparent perspective view for explaining the function of each part of the ink jet recording apparatus.
0 is a longitudinal sectional view for explaining the inkjet recording apparatus, FIG. 11 is an explanatory view of a scanning range of a carriage of the inkjet recording apparatus, and FIG. 12 is a BJ of the inkjet recording apparatus.
13 is an external view and a partially enlarged view of the cartridge, FIG. 13 is a configuration diagram of a recovery system unit of the ink jet recording apparatus, and FIG. 14 is a block diagram mainly showing a configuration of an electric unit of the ink jet recording apparatus.

The ink jet recording apparatus according to the first embodiment of the present invention will be described below with reference to FIGS. In FIG. 8, reference numeral 1 denotes a place where print media (paper) is set together by a sheet feeder. Reference numeral 2 denotes a sheet guide applied to the left side of the sheet so that the print medium is fed straight. Reference numeral 4 denotes a discharge port from which the printed medium is discharged. Reference numeral 5 denotes a discharge tray which can hold up to several tens of printed media. Reference numeral 6 denotes an operation panel on which a power button, an online button, and the like are arranged. 7 is a front cover for a BJ cartridge 19
Opened when replacing (see FIG. 12) or removing a jammed media.

In FIG. 9, reference numeral 8 denotes a pickup roller which serves to feed out the media set in the sheet feeder 1 one by one. Reference numeral 9 denotes a feed motor, which is transmitted to the feed roller 11 after the drive force generated by the drive motor 9 is reduced by the slowdown gear 10, and rotates the feed roller 11. Reference numeral 12 denotes a pressure roller, which is a non-driven roller that is pressed against the feed roller and is driven. The sheet fed by the pickup roller 8 to a position where the feed roller 11 and the pressure roller 12 are in contact with each other is fed from there by the conveying force of the feed roller 11.
13 ejects the medium on which printing has been completed to an ejection tray 5 by an eject roller. Reference numeral 14 denotes a spur, which serves to press the medium against the eject roller 13 and has a shape designed so that unfixed ink does not adhere after printing.

Reference numeral 19 denotes a BJ cartridge unit having a recording head and an ink tank. Reference numeral 151 denotes a carriage which is a component on which the BJ cartridge 19 is mounted, and which is configured to be easily attached and detached. 20 is a guide shaft, 21 is a guide rail, and the carriage 1
51 postures are supported.

The carriage 151 is a carriage belt 15
5 is fixed in one place. Carriage belt 155
Is a drive pulley 153 directly connected to the carriage motor 152
And an idler roller 154. A DC motor is used for the carriage motor 152.

Reference numeral 156 denotes a linear encoder scale, in which 360 lpi (line per inch, = 25.4)
(mm / 360 = 70.6 μm), the position of the carriage 151 can be accurately obtained by detecting the marks provided at equal intervals. Further, at the time of scanning of the carriage 151, the speed of the carriage can be calculated from the time interval of continuous detection of the linear encoder scale. With this configuration, the BJ cartridge 19 performs a main scanning operation by the driving force generated by the carriage motor 152.

A recovery unit 22 includes a cap 2 for preventing the recording head from drying when the printer is not used.
3, a pump 24 for applying a negative pressure to the print head via the cap 23 to suck ink in the print head, and a blade 25 for wiping the print head surface soiled by printing. Reference numerals 23, 24, and 25 correspond to those in FIG.
3 will be described.

In FIG. 10, a plurality of printing papers 45 stacked on the sheet feeder 1 are fed to the position of the feed roller 11 by rotating the pickup roller 8 twice. At this time, the pickup flag 42 provided on the pickup roller 8 shuts off the pickup roller sensor 46 as a photo sensor to notify the control board 111 of the state. Thereafter, as described above, the sheet is conveyed by the pressure roller 12 and the feed roller 11. A transmission roller 44 transmits the drive of the field roller 11 to the ejection roller 14. The BJ cartridge 19 is arranged on the upper side of the transmission roller 44, and forms a printing area.

The paper on which printing has been completed is discharged by the action of the spur 14 and the eject roller 13. The paper end flag 43 is arranged on the upstream side of the feed roller 11, and when there is a sheet there, shuts off the paper end sensor 41 and notifies the control board 11 of the cut off.
When the trailing edge of the sheet deviates from the position of the paper end flag 43, the control board 111 executes printing of a predetermined line from the information from the paper end sensor 41. Then, the sheet is forcibly ejected regardless of the presence or absence of data at that time.

The carriage 151 is fixed to a part of the carriage belt 155. An encoder sensor 157 fixed to the carriage 151 detects a mark on the linear encoder scale.

FIG. 11 illustrates the allocation of the carriage within the entire scanning range. Most of the “entire scanning range” is the “print area”. In this range, the carriage can run stably at a predetermined speed, and while scanning within a certain speed fluctuation range,
Printing is performed by ejecting ink droplets from the mounted recording head.

There are "acceleration / deceleration areas" on both sides of the printing area. When printing is performed in the entire width of the “print area”, acceleration to a predetermined speed and deceleration for reversing the scanning direction are completed in the “acceleration / deceleration area”.

The "wiping area" is an area in which a blade in the recovery system unit, which will be described later, and a nozzle forming surface of the recording head come into contact with each other, and an operation for removing attached ink droplets is performed. Preliminary ejection is also performed in this area.

The recording head is covered and protected by a cap 23 in the recovery system.
It must be at the "home position" on the right end in the figure. After the power-off end operation, the carriage is set at the "home position".

FIG. 12 includes an external perspective view of the BJ cartridge 19 (A), an enlarged view of the recording head section (B), and an enlarged view of the nozzle section (C). The BJ cartridge 19 includes an ink tank 19a and a recording head 19b. The cartridge includes four color ink tanks of black, cyan, magenta, and yellow and is capable of full-color printing.
The recording head 19b is provided with a nozzle row 19c. From here, ink droplets are ejected and recording is performed on paper. 19
d is the head face forming the nozzle. As shown in the enlarged view of the nozzle portion (C), the nozzle rows 19c are arranged in a line, and the interval is 1/720 inch, about 3
5.3 μM. A total of 320 nozzles are formed, Nos. 1 to 128 are black, Nos.
2 is cyan, Nos. 209 to 256 are magenta, No. 27
3-320 are yellow nozzles. No. 129
Reference numerals 144, 193 to 208, and 257 to 272 denote dummy nozzles. These nozzles are formed, but the ink supply path is not connected to the ink tank. In the wiping, a phenomenon in which ink of an adjacent color adhering to the head face enters the nozzle is reduced.

In this embodiment, when the ejection state of the BJ cartridge 19 is deteriorated, the above-mentioned 320 nozzles are covered with one cap 23, and the pressure inside the cap 23 is reduced, so that ink is simultaneously sucked from all the nozzles. I do.

Reference numeral 19d is a head face surface forming the nozzle row 19c. As shown in FIG. 12 (B), the head face 19d is substantially flat, and is brought into close contact with the nozzle row 19c of the cap 23 so as to cover the nozzle row 19c, thereby sucking ink.

FIG. 13 is a block diagram of the recovery system unit 22. FIG. 13A is a top view. 23 is a cap, 26 is a cap holder supporting the cap 23, and 24 is a pump. Reference numeral 25 denotes a blade, which performs wiping when the carriage 151 scans on the recovery system unit in the state shown in the figure, can slide in the direction shown by the arrow, and retracts when wiping is unnecessary. Reference numeral 31 denotes a recovery system motor, which is a vertical movement of the cap 23, a sliding movement of the blade 25, and a drive source of the pump 24.

FIG. 13B is a cross-sectional configuration view as viewed from the rear of the arrow A in FIG. The cap 23 is pressed against the recording head of the BJ cartridge 19. The cap holder 26 is instructed to be rotatable about a fulcrum. 2
Reference numeral 7 denotes a cap spring which applies a pressing force to the cap 23 via the cap holder 26. Reference numeral 28 denotes a cap release cam, which is rotated by 180 degrees from the state shown in the figure to press the cap holder 26 and release the pressure contact of the cap 23.

Reference numeral 29 denotes a tube, which is a cap holder 26.
Is connected to the cap 23 via a pipe provided in the.
The tube 29 passes through the inside of the pump 24 and constitutes a pump generally called a tube pump. Numeral 30 denotes a pump roller, which rotates in the direction of arrow d to form a tube 2.
9, the pressure in the connected cap 23 is reduced, and the ink in the BJ cartridge 19 can be sucked out.

In FIG. 14, reference numeral 111 denotes a control board for controlling each part of the apparatus. Reference numeral 100 denotes an MPU that receives a signal from each unit and issues a control signal to each unit according to the signal to control the entire apparatus. 101 is a ROM storing a control procedure program, 102 is a RAM used as a work area when executing control, 103
Is a timer for measuring time, 104 is a non-volatile data holding means (EEPROM or the like) for storing the accumulated number of recording sheets, the amount of waste ink, and the like, and 105 is an interface unit for exchanging signals with a host such as a computer. , 1
Reference numeral 06 denotes an indicator for notifying the user of the status of the apparatus, 107 denotes a key switch including a power switch, an online switch, etc., which is operated by the user to give commands to the apparatus, and 108 denotes a driver for driving the carriage motor 152. By changing the ON / OFF duty, a voltage having a pulse width suitable for the state is applied to the motor.

The signal detected by the encoder sensor 157 is passed to the MPU and converted into information on the position and speed of the carriage 151. 109 is a paper feed motor 9
, A driver 110 for driving the recording head, and a driver 112 for driving the recovery motor 31.

FIG. 1 is a graph showing a speed command curve and a change in acceleration of the carriage scanning acceleration control in the serial type ink jet printer according to the first embodiment of the present invention.
In the graph, a quintic functional speed curve is shown as an example, as compared with the cubic functional speed change curve already described in “Prior Art”.

A cubic function speed change curve is an acceleration change when a cubic function speed change is shown. The speed change curve shows that the speed gradually increases at the start of acceleration, and the target speed (600 mm / sec) is smooth near the completion of acceleration.
It is continuous. However, in the acceleration graph, the acceleration suddenly increases from 0 at the start of acceleration, and suddenly increases to 0 at the completion of acceleration.
And since the acceleration becomes 0 thereafter, it must be said that the acceleration is discontinuous.

A fifth-order functional speed change curve represents an acceleration change when a fifth-order functional speed change occurs. The speed change curve is similar to the cubic speed change curve, but the slope in the first half and the second half tends to be slightly smaller and the slope in the middle tends to be larger. In the graph of the acceleration, the intermediate acceleration peak is larger than that of the acceleration, but gradually increases from 0 at the start of the acceleration, and gradually returns to 0 at the completion of the acceleration. In other words, the driving force for tracing the speed change curve changes continuously as shown by the curve, so that more natural control with less loss is possible.

FIG. 15 shows a method similar to the result of FIG.
The “speed command value” is given by a quintic function speed change curve in FIG. 1 and is derived to a target speed of 600 mm / sec.
It is a result of simulation by MatLAB / Simulink. The parameters other than the speed command are the sixth
It is the same as the figure. The place where the speed change during acceleration was stepped during acceleration, which was improved in FIG.
It can be seen that further improvement is seen. Also, the amount of overshoot after reaching the target speed is reduced.

Next, a method of obtaining a quintic functional speed change command curve will be described. For example, assume the conditions as follows. (A) The initial speed is 0 mm / sec. (B) Acceleration is completed by scanning 20 mm. (C) The target speed is 600 mm / sec. (D) The acceleration at the start of acceleration and at the completion of acceleration is zero. (E) The differential value of acceleration is also 0 when acceleration starts and acceleration is completed.

If the velocity (v) is a quintic function of the time (t) and v = at ⁵ + bt ⁴ + ct ³ + dt ² + et + f, t = 0 and v = 0 from the condition (a). Therefore, since f = 0 acceleration (α) is a derivative of velocity, α = v ′ = 5at ⁴ + 4bt ³ + 3ct ² + 2dt + e From condition (d), t = 0 and α = 0. Therefore, taking the derivative of the acceleration at e = 0, α ′ = 20 at ³ +12 bt ² + 6ct + 2d. From condition (e), α = 0 at t = 0 from condition (e). Therefore, d = 0 acceleration completion time is set to t ₁ . From condition (d), t = t ₁
And α = 0. Therefore, 0 = 5at than _{^{1 4 + 4bt 1 3 + 3ct}} 1 2 ······ condition (c), at t = t _1, a v = 600. ^{_{Thus, 600 = at 1 5 + bt}} 1 4 + ct 1 3 ······ scanning distance (x) is because it is the integral of velocity (v), x = ∫vdt = (a / 4) t 4 + ( b / 3) t ^{3 From} condition (b), t = t ¹ and x = 20. Therefore, in 20 = (a / 6) t 1 6 + (b / 5) t 1 5 + (c / 4) t 1 from ⁴ .. Condition ^{(e), t = t 1} , is alpha '= 0 . Therefore, 0 = the _{^{20at 1 3 + 12bt 1 2 +}} 6ct 1 solve the ...... ,,, formula is _{simultaneous, t 1 = 1/15,} a = 2733750000, b = -455625000, the c = 20250000 .

FIG. 16 shows the scan distance (x), speed (v), acceleration (α), and acceleration derivative (α ′) expressed by the equation of the quintic function speed command curve obtained as described above. It is a graph which shows a change typically. The change in acceleration at the time of performing the quintic speed change gradually increases from zero at the start of acceleration, and gradually returns to zero at the completion of acceleration, and can be said to be continuous. This can be clearly seen from the fact that the graph of the acceleration derivative (α ′) is continuous.

(Other Embodiments) In the first embodiment, an example was described in which a DC motor was used as a drive source. However, the gist of the present invention is not limited to this.

In the first embodiment, a rotary type motor has been described, but the gist of the present invention is not limited to this. A linear type motor may be used.

In the first embodiment, the closed loop control has been described. However, the gist of the present invention is not limited to this. Open loop control may be used.

In the first embodiment, the speed command curve is described as a quintic function curve, but the gist of the present invention is not limited to this. For example, even if a curve is formed by a higher-order function or a function using a trigonometric function, an acceleration change curve obtained by differentiating the curve may change continuously and smoothly.

In the first embodiment, the so-called speed control in which the speed command curve is given, the speed is fed back, and the generated power of the drive source is calculated from the speed error, but the gist of the present invention is not limited to this. is not. For example, even in the case of so-called position control in which a position command curve corresponding to time is given, the command curve may be any command that requests the carriage to "continuously and smoothly change the force".

The present invention is based on the idea of "continuously and smoothly increasing the acceleration change curve, that is, the force to be accelerated". For example, control such as "control for correcting a static friction load" described below. Ingenuity is also a category.

As can be seen from FIG. 15 of the embodiment of the present invention, the actual movement of the carriage does not start scanning immediately after a speed command is issued, but remains stopped for about 0.02 seconds. is there. This is because as the speed command value gradually increases from 0, the torque generated in the motor gradually increases, but it does not overcome the static friction load that is preventing the carriage from moving. It is due to being in a state.

After that, when the carriage starts scanning at about 0.02 seconds, the speed command value is already 5 as shown in FIG.
It can be seen that the acceleration curve has reached 0 mm / sec, and the acceleration curve which is a derivative of the quintic function acceleration curve is about to reach 600 mm / sec ² as shown in FIG. It looks as though it has been reached.

That is, when the carriage starts scanning, the rate of increase in the force for accelerating the carriage is not already 0, but rather rather large, and smoothly changes from 0 as shown in FIG. You have not stood up. The force for accelerating the carriage is always the amount obtained by subtracting the friction load from the force generated by the motor, and it can be said that the presence of static friction hinders the application of a desired force.
Therefore, as shown in the simulation result of FIG.
It is conceivable that a step-like portion with a non-smooth speed still remains during acceleration.

As a control method for improving the above problems, for example, the following method can be considered. This is a method in which no speed command is given until the carriage starts scanning. After the command to start scanning, the force is increased relatively slowly, for example, at a constant rate of about 0.1 second, which can reach a level that can overcome static friction. A method of continuously and smoothly applying the motor generating force based on the motor generating force when the carriage starts slightly scanning can be considered. According to this method, smoother acceleration can be expected.

In the first embodiment, the carriage scanning control of the ink jet printer has been described, but the gist of the present invention is not limited to this. For example, control such as scanning by a flatbed scanner may be used.

[0068]

As described above, according to the present invention,
Responding to demands for higher image quality and higher resolution, especially high accuracy of ink droplet landing in the constant speed region immediately after the acceleration region, high quietness by suppressing noise and vibration during carriage scanning, especially during acceleration scanning, carriage acceleration An ink jet recording apparatus having a short distance and a small size can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a speed command curve and a change in acceleration of carriage scanning acceleration control of a serial type ink jet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a configuration of a conventional carriage drive system.

FIG. 3 is a schematic diagram of a conventional ridge scanning speed control system.

FIG. 4 is a conventional carriage scanning speed change graph (step-like speed command).

FIG. 5 is a conventional carriage scanning speed change graph (linear function speed command).

FIG. 6 is a conventional carriage scanning speed change graph (cubic function speed command).

FIG. 7 is a graph of a runner distance, a speed, and an acceleration with respect to time, obtained by a conventional cubic speed command curve.

FIG. 8 is an external perspective view of the ink jet recording apparatus according to the embodiment of the present invention.

FIG. 9 is a perspective view illustrating the function of each part of the ink jet recording apparatus according to the embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of the ink jet recording apparatus according to the embodiment of the present invention.

FIG. 11 is an explanatory diagram of a scanning range of a carriage of the inkjet recording apparatus according to the embodiment of the present invention.

FIG. 12 is an external view and a partially enlarged view of a BJ cartridge of the ink jet recording apparatus according to the embodiment of the present invention.

FIG. 13 is a configuration diagram of a recovery system unit of the inkjet recording apparatus according to the embodiment of the present invention.

FIG. 14 is a block diagram mainly showing a configuration of an electric unit of the inkjet recording apparatus according to the embodiment of the present invention.

FIG. 15 is a graph of a carriage scanning speed change (fifth order functional speed command) of the ink jet recording apparatus according to the embodiment of the present invention.

FIG. 16 is a graph of a runner distance, a speed, an acceleration, and a derivative of the acceleration with respect to time, which are obtained from a quintic function speed command curve for carriage scanning speed control of the inkjet recording apparatus according to the embodiment of the present invention. .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet feeder 2 Sheet guide 4 Paper discharge port 5 Paper discharge tray 6 Operation panel 7 Front cover 8 Pickup roller 9 Paper feed motor 10 Slow down gear 11 Paper feed roller 12 Pressure roller 13 Ink jet roller 14 Spur 19 BJ cartridge 20 Guide shaft 21 Guide rail 22 Recovery unit 23 Cap 24 Pump 25 Blade 26 Cap holder 27 Cap spring 28 Cap release cam 29 Tube 30 Pump roller 41 Paper sensor 42 Pickup flag 43 Paper end flag 44 Transmission roller 45 Recording paper 46 Pickup roller sensor 111 Control board 100 MPU 101 ROM 102 RAM 103 Timer 104 Non-volatile data Holding means (EEPROM, etc.) 105 Interface section 106 Indicator section 107 Key switch 108 Carriage motor driver 109 Paper feed motor driver 110 Recording head driver 112 Recovery system motor driver 151 Carriage 152 DC motor 153 Driving pulley 154 Idler pulley 155 Rubber belt 156 Linear encoder scale 157 Linear encoder sensor

Claims (5)

[Claims] When accelerating a mechatronic device using a motor as a driving source, the acceleration change of a controlled object should be “continuous and smooth”, or the change of the derivative of the controlled object should be “continuous”. A motor acceleration control method characterized by issuing a command as much as possible. 2. A serial recording apparatus comprising: a recording head for recording on a recording medium; scanning means (main scanning means) for scanning the recording head; and conveying means (sub-scanning means) for conveying the recording medium. 2. The motor acceleration control method according to claim 1, wherein the method is a method for controlling the scanning unit in an apparatus. 3. A motor as a driving source of the scanning means,
The motor acceleration control method according to claim 2, wherein the motor is a rotary type motor. 4. In the closed loop control, a "speed command curve" is used, and in the open loop control, an "acceleration table"
4. The method according to claim 3, wherein a quintic function curve is used.
3. The motor acceleration control method according to 1. 5. A quintic function speed command curve is provided from the moment when the force generated by the drive source under the Claude loop control overcomes a friction load or the like and the controlled object starts operating. The motor acceleration control method according to claim 4, wherein: