JP2001347718A - Speed controller, recorder, and image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed controller, a recorder and an image reader in which stability of the moving speed of a mover can be enhanced while taking account of the effect of a power transmission means such as a belt having a specified spring constant, while meeting the requirement of increase in the size of the mover. SOLUTION: In an image recorder for moving a carriage 151 with a driving force being transmitted from a motor 152 through a belt 155 having a specified spring constant, a speed controller for controlling the moving speed of the mover averages the moving speed of the carriage 151 detected by a linear encoder sensor 157 and the winding speed of the belt 155 detected by a belt encoder sensor 158 and controls the motor 152 based on the average speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control device, a recording device, and an image reading device. More specifically, the power of a moving body is transmitted through power transmission means such as a belt having a predetermined spring constant. The present invention relates to a speed control device of a device to be used, and an image recording device and an image reading device including the same.

The present invention can be suitably applied to a serial recording apparatus or an image reading apparatus included in an information processing apparatus such as an office or industrial copier, facsimile, word processor, or computer. it can.

[0003]

2. Description of the Related Art For example, as a configuration of a scanning device of a carriage in a serial recording apparatus, a toothed portion is provided between a driving pulley directly connected to a carriage motor as a driving source and an idler pulley located on the opposite side. In general, a rubber belt (or a toothless steel belt or a wire) is stretched with a predetermined tension, and a slidable carriage is connected to the toothed belt. Open-loop control type using a pulse motor (including a hybrid motor)
It can be classified into a closed loop control type using a DC motor or the like. The control type to which the present invention can be applied is the latter closed loop control type.

FIGS. 15A and 15B are explanatory diagrams of a closed loop control type speed control system in a serial recording apparatus. The driving force of the carriage motor 152 controlled by the motor driver 10 is
3 is transmitted to the carriage 151 via the belt 155, and the scanning speed of the carriage 151 is detected by the linear encoder sensor 157.

[0005] Unlike the open loop control, the closed loop control requires a detecting unit for detecting speed information of a control target and outputting the speed information to a control circuit. In many cases, a linear encoder is used as the detection unit. Generally, an optical linear encoder sensor 157 is mounted on the carriage 151, and a transparent linear encoder scale is fixedly stretched over the scanning range of the carriage 151, and a light-shielding mark printed on the linear encoder scale is provided. The detection is performed by the linear encoder sensor 157. The scanning position of the carriage 151 can be detected by counting the number of light-blocking marks detected by the linear encoder sensor 157, and the scanning of the carriage 151 can be performed based on the time interval when the light-blocking marks are continuously detected. Speed can be calculated.

The target speed of the carriage 151 is:
It is given as a "speed command" (the command value is also called "speed command value"). In general, the "speed command" is such that the speed is increased at a constant rate and is led to a target speed, as shown in FIG. The speed calculation circuit 161 is provided with the encoder sensor 1
The current “scanning speed” of the carriage 151 (the speed value is also referred to as “scanning speed value”) is calculated from the detection signal 57 and the clock signal built in the printing apparatus. And
The value obtained by subtracting the “scan speed value” from the “speed command value” is regarded as a “speed error” that is insufficient with respect to the target speed.
62 is input.

As shown in FIG. 3, a PID operation circuit 162 uses a proportional gain Gp, an integral gain Gi, a differential gain Gd, and an overall gain G to carry a carriage motor (DC motor) 152 by a technique called PID operation. Energy to be given to the motor driver 10
8 is output. That is, the PID operation circuit 162 multiplies the speed error value by the proportional gain Gp by proportional processing, integrates (ie, accumulates) the speed error value by integral processing, and multiplies the integrated value by the integral gain Gi. And differentiate the speed error value by differential processing (that is, calculate the difference from the previous speed error value)
Then, the differential value is multiplied by a differential gain Gd. Further, the total value is multiplied by the overall gain G, and the result is output to the motor driver 108.

In the case of this embodiment, the motor driver 108 keeps the applied voltage of the carriage motor 152 constant and changes the pulse width of the applied voltage (hereinafter, referred to as the following).
“PWM (Pulse Width Modulate) control”), which adjusts the current value by changing the duty of the applied voltage. As a result, the energy given to the carriage motor 152 is adjusted, and speed control is performed.

The rotational torque of the carriage motor 152 is
It is transmitted to the carriage 151 via the drive pulley 153 and the belt 155 connected thereto, and the carriage 1
The scanning operation of 51 is performed.

In such a control method, the necessary torque is generated when necessary from the carriage motor 152, and the fluctuation of the carriage scanning speed due to the fluctuation of the sliding load of the carriage 151 is suppressed to a small level. I was

[0011]

In recent years, the image quality of a color recorded image by an ink jet recording apparatus has been remarkably advanced, and a higher image quality called a photographic image quality has been required. There is an increasing demand for higher resolution in order to improve the quality of recorded images. For example, a device having a resolution of about 1440 dpi has been commercialized beyond a resolution of about 360 dpi. In the case of a resolution of 360 dpi, the interval between adjacent ink dots formed on the recording medium (hereinafter, referred to as “interval between adjacent dots”) was 70.6 μm. However, when the resolution is 1440 dpi, the interval between adjacent dots is 17.6 μm (= 25.4 mm / 144).
0), and in an ink jet recording system for expressing a color by ejecting ink droplets of different colors into a predetermined recording area, the demand for landing accuracy of the ink droplets has been increased to the order of microns.

In a serial type ink jet recording apparatus in which an ink jet recording head is mounted on a carriage 151, the carriage 15 is used when an ink droplet is ejected.
One speed determines the flight path of the ink droplet and affects the landing position of the ink droplet. Therefore, in order to maximize the accuracy of the ink droplet landing position, the carriage 15
It is required that the fluctuation of the scanning speed of 1 be as close to zero as possible. Further, in recent years, the serial recording apparatus has been expanded and used for industrial uses such as textile printing, and the scanning distance of the carriage 151 has been increased.
The weight of 1 has also increased, and its constant velocity control has become even more difficult.

FIG. 16 is a diagram for explaining a speed change when the carriage 151 is feedback-controlled.
In the case of 6, the proportional gain Gp of the PID operation circuit 162 was set to 1 (Gp = 1), and the integral gain Gi, the differential gain Gd, and the overall gain G were set to predetermined values. FIG.
FIG. 17 is an enlarged view of a graph from 0.15 sec to 0.4 sec in FIG. 16.

In FIGS. 16 and 17, the broken line A on the trapezoid is a speed command value, the curve B is the scanning speed of the carriage 151, and the curve C is the winding and unwinding speed of the belt 155 at the position of the driving pulley 153 ( Hereinafter, these are collectively referred to as “winding speed”). The driving pulley 153 changes the winding direction and the winding direction of the belt 155 according to the rotation direction. The carriage scanning speed B is set to a target speed of 264.6 mm / sec.
It is in the range of 260.8 mm / sec to 268.9 mm / sec, and the variation rate is within about 3.1%. However, it is desired that the fluctuation rate be smaller when the target of the ink droplet landing accuracy is increased as described above.

It should be noted here that the carriage scanning speed B and the belt winding speed C do not match. This is due to the expansion and contraction of the belt 155. In the case of a general rubber belt, the elastic modulus is increased by using graphite, carbon fiber, or the like as a core material. However, the elastic modulus of the belt 155 and the carriage motor 15
Due to the natural vibration determined by the moment of inertia of the drive pulley 2 and the drive pulley 153 and the moment of inertia of the carriage 151, a relative speed occurs between the carriage scanning speed B and the belt winding speed C, and they do not match.

The method of reducing the fluctuation of the carriage scanning speed B is divided into an "acceleration region" where the speed error tends to increase and a "constant speed region" where the speed error converges to some extent. It is conceivable to increase the proportional gain Gp only in the “constant speed region”.

FIG. 18 is an explanatory diagram of a speed change when the proportional gain Gp is increased to 3 (Gp = 3) only in the "constant speed region" and other conditions are set to be the same as those in FIG. . The result is obvious at a glance, and an oscillation phenomenon occurs, resulting in speed control failure.

FIG. 19 shows a driving pulley 153 as feedback information instead of the scanning speed of the carriage 151.
FIG. 4 is an explanatory diagram of a speed control system when a winding speed of a belt 155 is used. The reason for feeding back the winding speed of the belt 155 by the driving pulley 153 instead of the rotation speed of the output shaft of the carriage motor 152 is that the rotation speed of the carriage motor 152, that is, the angular speed, is calculated using a rotary encoder provided on the output shaft of the carriage motor 152. Can be controlled to be constant, the driving pulley 15
This is because, due to the eccentricity of 3, that is, the radius of the drive pulley 153, a factor of variation in the scanning speed of the carriage 151 remains.

FIG. 20 shows that the speed control system shown in FIG.
FIG. 21 is an explanatory diagram of a speed change when the carriage 151 is feedback-controlled. In the case of FIG. 20, the proportional gain Gp of the PID calculation circuit 162 is set to 1 (Gp = 1) as in the case of FIG. Further, the integral gain Gi, the differential gain Gd, and the overall gain G were set to predetermined values. FIG. 21 is a graph showing the relationship between 0.15 sec and 0.4 sec in FIG.
It is an enlarged view of the graph up to c. The variation rate of the carriage scanning speed B is about 3.1% as in the case of FIG. 16, and is substantially the same as the case where the scanning speed of the carriage 151 is fed back.

FIG. 22 is an explanatory diagram of a speed change when the proportional gain Gp is increased to 3 (Gp = 3) only in the "constant speed region" and other conditions are set to be the same as those in FIG. . The result is obvious at a glance, and an oscillation phenomenon occurs, resulting in speed control failure.

As is apparent from the above specific example, when the control gain is increased to suppress the speed fluctuation width of the carriage 151, when the control gain exceeds a certain limit, the elasticity of the belt 155 is reduced. This causes an oscillation phenomenon that amplifies the resulting natural vibration. As a method of improving such a situation, it is conceivable to increase the spring constant of the belt 155 or to reduce the fluctuation width of the sliding load of the carriage 151. However, both methods are practically difficult.

An object of the present invention is to improve the stability of the moving speed of a moving body in consideration of the influence of power transmission means such as a belt having a predetermined spring constant and to increase the size of the moving body. An object of the present invention is to provide a speed control device, a recording device, and an image reading device capable of responding to the following.

[0023]

A speed control device according to the present invention relates to a moving body which is moved by a driving force transmitted from a driving source via power transmission means having a predetermined spring constant, and controls the moving speed thereof. A first speed detecting means for detecting a moving speed of the moving body; a second speed detecting means for detecting a moving speed of the power transmitting means; Speed averaging processing means for averaging the speeds detected by the second detection means to obtain an average speed, and control means for controlling the drive source based on the average speed. I do.

The recording apparatus according to the present invention is a serial recording apparatus which moves a movable body on which a recording head can be mounted by a driving force transmitted from a driving source via a power transmission means having a predetermined spring constant. It is characterized by including the above-mentioned speed control device for controlling the speed of the moving body.

An image reading apparatus according to the present invention is a serial image reading apparatus which moves a movable body on which a scanner can be mounted by a driving force transmitted from a driving source via a power transmission means having a predetermined spring constant. And a speed control device for controlling the speed of the moving body.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a carriage scanning mechanism in a serial type ink jet recording apparatus to which the present invention can be applied. 8 is an external perspective view of the ink jet recording apparatus, FIG. 9 is a perspective view for explaining the internal structure of the ink jet recording apparatus, FIG. 10 is a longitudinal sectional view of the ink jet recording apparatus, and FIG. 12 (a), 12 (b) and 12 (c) are explanatory views of an ink jet cartridge which can be mounted on the ink jet recording apparatus, and FIGS. FIG. 14B is an explanatory diagram of a recovery system unit provided in the inkjet recording apparatus, and FIG. 14 is a block diagram of a control system of the inkjet recording apparatus.

First, an ink jet recording apparatus to which the present invention can be applied will be described with reference to FIGS.

In FIG. 8, reference numeral 1 denotes a sheet feeder on which sheets as recording media are set together.
Reference numeral 2 denotes a sheet guide, which strikes the left side of the sheet to adjust the posture so that the sheet is fed straight. Reference numeral 4 denotes a discharge port from which a recorded sheet after image recording is discharged. Reference numeral 5 denotes a paper discharge tray, which holds up to several tens of recorded sheets. Reference numeral 6 denotes an operation panel on which a power button, an online button, and the like are arranged. Reference numeral 7 denotes a front cover, which is an inkjet cartridge 19.
Opened when replacing (see FIG. 12) or removing jammed paper.

In FIG. 9, reference numeral 8 denotes a pickup roller, which feeds out the sheets set in the sheet feeder 1 one by one. 9 is a feed motor whose driving force is
The speed is reduced by the slowdown gear 10 and then transmitted to the feed roller 11 to rotate the feed roller 11. Reference numeral 12 denotes a pusher roller, which is driven by being pressed against the feed roller 11. The sheet fed by the pickup roller 8 to the position where the feed roller 11 and the pusher roller 12 come into contact with each other is
Is further fed by the conveying force of Reference numeral 13 denotes an eject roller, which discharges the recorded paper to the discharge tray 5. Reference numeral 14 denotes a spur that presses the sheet against the eject roller 13 and has a shape such that unfixed ink on the recorded sheet does not adhere. Reference numeral 131 denotes a carriage on which the inkjet cartridge 19 can be mounted. 20 is a guide shaft, 21 is a guide rail, and the carriage 151 is supported by these.

In this embodiment, a DC motor is used as the carriage motor 152. A carriage belt 155 is stretched between a drive pulley 153 directly connected to the carriage motor 152 and an idler pulley 154.
The carriage belt 155 of this embodiment is a steel belt, which has fine slits formed by etching, and the slit is detected by a belt encoder sensor 158 disposed very close to the drive pulley 153. 153 can accurately obtain the amount of winding and unwinding of the belt 155 (hereinafter, these are collectively referred to as “winding amount”). The driving pulley 153 changes the winding direction and the feeding direction of the belt 155 according to the rotation direction. Reference numeral 156 denotes a linear encoder scale fixedly mounted on the printer chassis.
Is detected by the linear encoder sensor 157 (see FIG. 14) mounted on the carriage 151, the position information of the carriage 151 can be obtained. Since the carriage 151 is connected to the carriage belt 155, the carriage motor 152
Is moved in the main scanning direction together with the ink jet cartridge 19 by the driving force.

Numeral 22 denotes a recovery system unit, as shown in FIG. 13, which is a cap 23 for preventing the recording head from drying when the recording apparatus is not used, and by applying a negative pressure to the recording head via the cap 23. A pump 24 for sucking ink in the recording head, a blade 25 for wiping the head surface of the recording head dirty by the recording operation, and the like are provided.

In FIG. 1, a carriage belt 155 made of steel as an endless body is provided with a carriage motor 152.
Pulley 153 and idler pulley 154 directly connected to
And between them and with sufficient tension in the direction of arrow B. The shaft position of the idler pulley 154 is fixed to the linter chassis in a state where the belt 155 has sufficient tension. The belt 155 has
360 lpi (line per inch: = 2.54 mm / 3
The slits are provided at regular intervals (60 = 70.6 μm). As described above, the slit is connected to the drive pulley 15.
3 is detected by the belt encoder sensor 158 in the vicinity of
The winding amount of the belt 155 and the feeding speed (hereinafter, these are collectively referred to as “winding speed”) can be calculated from the time interval of the detection signal of the encoder sensor 158. .

The linear encoder scale 156 also has 360 lpi (line per inch: 2.54 mm).
/360=70.6 μm) at equal intervals. As described above, the mark is placed on the carriage 15.
By detecting with the linear encoder sensor 157 fixed to 1, the position of the carriage 151 can be accurately detected. When the carriage 151 is operated, the scanning speed of the carriage 151 can be calculated from the time interval of the detection signal of the linear encoder sensor 157.

For example, when the carriage motor 152 has an arrow C
When the carriage 151 is scanned in the direction indicated by the arrow A so that the belt 155 is wound around the driving pulley 153, the winding speed of the belt 155 and the scanning speed of the carriage 151 are slightly different. This is because the belt 155 connecting the driving pulley 153 and the carriage 151 has elasticity. That is,
This is because the belt 151 slightly expands and contracts. The drive pulley 153 and the carriage 151 move with a velocity component caused by natural vibrations determined by their own inertia (moment of inertia) and the spring constant of the belt 155.

In FIG. 10, a plurality of sheets 45 stacked on the sheet feeder 1 are
By rotating, it is fed to the position of the feed roller 11. At this time, the pickup flag 42 provided on the pickup roller 8 interrupts the optical path of the photo sensor serving as the pickup roller sensor 46, thereby detecting that the sheet 45 has been sent out, and controlling the control board 111 (see FIG. 14). Output to the above control circuit. The paper 45 is thereafter conveyed by the pressure roller 12 and the feed roller 11 as described above. A transmission roller 44 transmits the rotation of the feed roller 11 to the ejection roller 13. A position above the transmission roller 44 is a recording area where the cartridge 19 is provided. The paper 45 after recording is discharged by the spur 14 and the eject roller 13.

The paper end flag 43 is provided on the upstream side of the feed roller 11, and when the paper 45 is present, the optical path of the paper end sensor 41 is cut off.
Output to the control circuit on the control board 111 (see FIG. 14). When the trailing edge of the paper 45 deviates from the position of the paper end flag 43, the control circuit on the control board 111 executes the recording for a predetermined line from that time based on the information from the paper end sensor 41. The paper 45 is forcibly discharged regardless of the presence or absence of the recording data.

As described above, the carriage belt 155
A carriage 151 is connected to a part of the linear encoder sensor 15.
7 detects a mark on the linear encoder scale 156.

In FIG. 11, most of the entire scanning range D of the carriage 151 is a recording operation area D1. This area D1 is an area where the carriage 151 can run stably at a predetermined speed, and while scanning at a speed within a certain fluctuation range,
An image is recorded on the paper 45 by ejecting ink droplets from the recording head of the mounted cartridge 19.
On both sides of the area D1, there are acceleration / deceleration areas D2 and D3. When printing is performed by scanning the carriage 151 over the entire width of the area D1, acceleration to a predetermined speed and deceleration for reversing the scanning direction are completed in the areas D2 and D3. D4 is a wiping area. In this area, the blade 25 in the recovery system unit 22 comes into contact with the nozzle forming surface of the recording head to remove ink droplets attached to the nozzle forming surface. Further, in order to keep the ink ejection state of the recording head good, a recovery operation of ejecting ink that is not applied to image recording from the recording head is also performed in this area D4. The recording head is covered and protected by a cap 23 in the recovery system unit 22. At that time, the carriage 151 needs to be located at the home position P at the right end. The carriage 151 is set at the home position P after the end of the recording operation in which the power is turned off.

FIG. 12A is an external perspective view of the ink jet cartridge 19, FIG. 12B is an enlarged perspective view of the recording head portion, and FIG. 12C is an enlarged view of a nozzle portion in the recording head portion. FIG. Cartridge 19
Consists of an ink tank section 19a and a recording head section 19b. The cartridge 19 of the present example is capable of full-color recording, and the ink tank section 19a includes an ink tank that stores four color inks of black, cyan, magenta, and yellow. The recording head unit 19b has a nozzle row 1
9c is formed, and an image is recorded by ejecting ink droplets from each nozzle. The method of discharging ink is not limited at all, and for example, a method of applying heat energy as the discharge energy of ink using an electrothermal converter may be adopted.

Reference numeral 19d denotes a head face surface (nozzle forming surface) on which nozzles are formed. Nozzle row 19c
Are formed in one row as shown in FIG. 12C, and the interval between nozzles is 1/720 inch (about 35.3 μm). A total of 320 nozzles are formed. 1
Nos. To 128 are nozzles for discharging black ink. 14
Nos. 5 to 192 are nozzles for discharging cyan ink. 20
9 to 256 are nozzles for discharging magenta ink. No. 2
73 to 320 are nozzles for discharging yellow ink.
In addition, No. Nos. 129 to 144; 193-208.
And No. 257 to 320 are dummy nozzles,
These are formed as nozzles, but are not connected to the ink supply path. These dummy nozzles prevent ink of adjacent colors adhering to the head face 19d from entering the nozzles during wiping.

In the case of this example, when the ink ejection state of the recording head section 19b deteriorates, all the 320 nozzles are set to 1
By covering with one cap 23 and depressurizing the inside of the cap 23, ink is simultaneously sucked from all the nozzles. The head face 19d is substantially flat as shown in FIG. 12B, and the cap 23 is brought into close contact with the head face 19d by pressure so as to cover the nozzle row 19c, and then ink is sucked.

FIG. 13A is a plan view of the recovery system unit 22. FIG. 23 is a cap, 26 is a cap holder for supporting the cap 23, 24 is a pump, and 25 is a blade. The blade 25 is slidable in the direction of arrow a. When the carriage 151 is scanned above the recovery system unit 22 at the position shown in FIG. 13A, the wiping by the blade 25 is performed. When wiping is not required, the evacuating device is retracted to the left in FIG. Reference numeral 31 denotes a recovery motor serving as a driving source for the up / down operation of the cap 23, the sliding operation of the blade 25, and the operation of the pump 24.

FIG. 13B is a sectional view of the recovery system unit 22 as viewed from the direction of arrow A in FIG. In the figure, the cap 23 is at a position where the cap 23 comes into pressure contact with the recording head portion 19 b of the cartridge 19. Cap holder 26
Are supported rotatably about a fulcrum about 26a. Reference numeral 27 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 position shown in FIG.
Release the pressure contact. Reference numeral 29 denotes a tube which is connected to the cap 23 via a tube provided in the cap holder 26. Tube 29 passes through pump 24,
It constitutes a pump generally called a tube pump. Reference numeral 30 denotes a pump roller which squeezes the tube 29 by rotating in the direction of the arrow d and lowers the air pressure in the cap 23 connected thereto, thereby sucking ink from the nozzles of the recording head 19b.

In the control system shown in FIG. 14, reference numeral 111 denotes a control board on which a control circuit for controlling each section of the apparatus is formed. An MPU 100 controls the entire apparatus by issuing control signals based on various input information. Reference numeral 101 denotes an RO storing a control procedure program.
M and 102 denote a RAM used as a work area when executing control, 103 denotes a timer for measuring time, and 104 stores the accumulated number of sheets of paper 24, the amount of waste ink discharged from the cartridge 19, and the like. Non-volatile data holding means (such as an EEPROM). 1
Reference numeral 05 denotes an interface unit for exchanging signals with a host device such as a computer, and reference numeral 106 denotes an indicator unit for notifying a user of the status of the apparatus. 107
Is a key switch operated by a user to give a command to the apparatus, and includes a power switch, an online switch, and the like. Reference numeral 108 denotes a driver for driving the carriage motor 152, which applies a voltage having a pulse width according to a situation to the carriage motor 152 by changing the ON / OFF duty of the voltage.

The detection signals of the linear encoder sensor 157 and the belt encoder sensor 152 are passed to the MPU 100, and the respective carriage scanning speed and belt winding speed are calculated and used for speed control and position control of the carriage motor 152. 109 is a driver for driving the paper feed motor 9, and 110 is the cartridge 1
Driver 112 for driving the recording head section 19b
Is a driver for driving the recovery system motor 31.

FIGS. 2A and 2B are explanatory diagrams of a carriage scanning speed control system. As described above with reference to FIG.
The same parts as those in (b) are denoted by the same reference numerals, and description thereof is omitted.

The DC motor as the carriage motor 152 is controlled by a method called PID control or classic control. The speed control unit 113 determines that the MPU 100 in FIG.
2. It corresponds to a part that functions using the timer 103. The speed control unit 113 obtains information on the energy applied to the carriage motor 152 at the present time, as described later, and the motor driver 108 drives the carriage motor 152 based on the information. Motor driver 108
15A, the energy applied to the carriage motor 152 is adjusted by PWM (Pulse Width Modulate) control that changes the pulse width of the applied voltage while keeping the applied voltage of the carriage motor 152 constant, as in FIG. Thus, the generated torque is controlled. The rotation torque of the carriage motor 152 is transmitted to the carriage 151 via the driving pulley 153 and the belt 155 connected thereto, and causes the carriage 151 to scan.

In the case of this example, as described above, by providing the belt encoder sensor 158 in addition to the linear encoder sensor 157, the belt winding speed is detected together with the carriage scanning speed. The linear encoder sensor 157 outputs a signal each time the carriage 151 is scanned by 1/360 inch. Similarly, the belt encoder sensor 158 detects that the belt 155 is 1/360
A signal is output each time the inch is wound. The speed calculation circuit 161 counts the input interval of the detection signal of the encoder sensor 157 using, for example, a 10 MHz timer, sets the count value to Cl, and sets a preset speed conversion constant Cv to the count value Cl. To calculate the “carriage scanning speed”. Similarly, the speed calculation circuit 163 counts the input interval of the detection signal of the belt encoder sensor 158 using, for example, a 10 MHz timer, sets the count value to Cb, and sets a preset speed conversion constant Cv. Is divided by the count value Cb to calculate a “belt winding speed (belt retracting speed)”. Therefore, the "carriage scanning speed"
Is calculated as Cv / Cl, and the “belt winding speed” is calculated as Cv / Cb.

Reference numeral 159 denotes a speed averaging circuit.
The rotor of the motor 152, the drive pulley 153, and the key
Weight according to the moment of inertia of the
And two speeds, "carriage scanning speed" and "bell
Averaging the “winding speed” to calculate the “average speed”
You. In the case of this example, the weight of the carriage 151 is 400 g,
The pitch circle radius of the driving pulley 153 is 5.165 mm.
Therefore, the moment of inertia of the carriage 151 is 1067
1 (g · mm^Two), And the carriage motor 152
Moment of inertia with the addition of the rotor and drive pulley 153 is
4998 (g · mm ^Two), And the following equation shows “averaging speed
Degree "is calculated.

Averaging speed = (Cv / Cl × 4998 + C)
v / Cb × 10671) ÷ (4998 + 10671) The target speed of the carriage 151 is given as a “speed command” (the command value is also referred to as a “speed command value”).
The “speed command” uses a general method of increasing the speed at a fixed rate and leading to a target speed as shown in FIG. The value obtained by subtracting the “scanning speed” from the “speed command value” is input to the PID calculation circuit 162 as a “speed error” that is insufficient for the target speed.

As described above, the PID operation circuit 162 uses the technique called PID operation as shown in FIG.
Using a proportional gain Gp, an integral gain Gi, a differential gain Gd, and an overall gain G, a carriage motor (DC motor)
The amount of energy to be given to 152 is calculated and output to the motor driver 108. That is, the PID operation circuit 162 multiplies the speed error value by the proportional gain Gp by proportional processing, integrates (ie, accumulates) the speed error value by integral processing, and multiplies the integrated value by the integral gain Gi. Further, the speed error value is differentiated by differential processing (that is, a difference from the previous speed error value is calculated), and the differential value is multiplied by a differential gain Gd. Furthermore, the total value is multiplied by the total gain G,
The result is output to the motor driver 108.

FIG. 4 is a diagram for explaining a speed change when the carriage 151 is feedback-controlled. In the case of FIG. 4, the proportional gain Gp of the PID calculation circuit 162 is set to 1
(Gp = 1), and the integral gain Gi and the differential gain G
d, the overall gain G was set to a predetermined value. FIG.
It is an enlarged view of the graph between 0.15 second and 0.4 second in FIG. 4 and 5, the broken line A on the trapezoid is the "speed command value", the curve B is the "carriage scanning speed", the curve C is the "belt winding speed", and the curve D is the "averaging speed". . The carriage scanning speed B is 262.4 mm against the target speed of 264.6 mm / sec.
/ Sec to 267.0 mm / sec, and the variation rate is about 3.3%.

FIG. 6 shows that the proportional gain Gp is raised to 4 (Gp = 4) only in the "constant speed region",
FIG. 9 is an explanatory diagram of a speed change when the same setting is made as in the case of FIG. FIG. 7 is a graph showing 0.45 seconds from 0.15 sec in FIG.
It is an enlarged view of the graph until ec. Proportional gain Gp
No oscillation phenomenon occurred even when the value was raised to 4, and it was confirmed that the gain region in which the oscillation phenomenon did not occur could be expanded by the averaging process described above. In addition, the carriage scanning speed B is set to 2 to the target speed of 264.6 mm / sec.
The variation was in the range of 60.5 mm / sec to 269.2 mm / sec, the fluctuation rate was suppressed to about 1.7%, and the effect of increasing the gain was confirmed.

It is considered that these effects are due to the fact that the relative speed component between the carriage scanning speed B and the belt winding speed C has been removed. The relative velocity components between the velocities B and C are caused by the natural vibration determined by the elastic coefficient of the belt 155, the inertia moment of the motor 152 and the driving pulley 153, and the inertia moment of the carriage 151.

(Second Embodiment) The applicable range of the present invention is as follows.
The present invention is not limited to the range of the first embodiment, that is, the scanning control of the carriage in the serial type ink jet recording apparatus, but includes various kinds of moving bodies that are moved via transmission means (represented by a belt) having a spring constant. It can be widely applied for movement control. For example, the present invention can be applied as a control device for a serial type image reading device that scans a flatbed scanner.

(Third Embodiment) The driving source of the moving body is not limited to the DC motor of the first embodiment, but may use various motors such as an ultrasonic motor, an AC motor, and a pulse motor. Can be.

(Fourth Embodiment) When a belt is used as the transmission means having a spring constant, the belt is not limited to the rubber belt containing the core material as in the first embodiment, but is made of steel. Various kinds of belts and wires can be used.

(Fifth Embodiment) The means for detecting the moving speed of a moving body such as a carriage is not limited to the optical encoder sensor as in the first embodiment, but various sensors can be used. . For example, a magnetic encoder mounted on a carriage as a moving body, a laser Doppler speed detector fixed to a printer chassis, or the like can be used.

(Sixth Embodiment) The detecting means of the moving speed of the transmitting means typified by a belt detects the slit provided in the steel belt by a transmission type optical encoder sensor arranged near the driving pulley. It is not limited to only the method of one embodiment. For example, as another first method, a mark printed on the back surface of the rubber belt may be read by a reflective optical encoder sensor provided near the driving pulley. As another second method, a magnetic encoder sensor provided near the drive pulley so as to be slidable in the axial direction of the drive pulley is used.
The magnetized portion of the wire may be read. Also,
Another third method is to irradiate a laser from a laser Doppler velocimeter on the back surface of the rubber belt wound around the driving pulley to detect the speed of the rubber belt,
The difference between the back surface position of the rubber belt and the pitch circle diameter may be corrected by calculation.

(Seventh Embodiment) When a belt is used as the transmission means, the pulley to be bridged is limited to a combination of one drive pulley and one idler pulley as in the first embodiment. Not done. For example, 1
It may be a combination of one drive pulley and two idler pulleys, or a combination of one drive pulley and three idler pulleys.

(Eighth Embodiment) In the first embodiment, in order to accurately detect the belt winding speed,
A slit provided in the steel belt is detected by a transmission optical encoder sensor arranged near the driving pulley. However, the method of detecting the moving speed of the transmission means such as a belt in the present invention is not limited to such a method. For example, simply, the angular velocity detected by a rotary encoder directly connected to the motor shaft may be multiplied by the average pitch circle radius of a transmission means such as a belt, and the value may be used as the belt feeding speed (winding speed). A certain effect can be expected also by such a method.

(Ninth Embodiment) In the first embodiment, the carriage of the serial recording apparatus as a reciprocating body has been described as the object of speed control. However, the speed control object in the present invention is not limited to this and is arbitrary,
For example, a roller driven via a driving pulley and a belt may be used.

(Tenth Embodiment) The drive source to be speed-controlled is not limited to a rotary motor. For example, an electromagnetic induction type or ultrasonic drive type linear motor may be used.

(Eleventh Embodiment) In the first embodiment, the speed averaging processing circuit 159 obtains the averaging speed by the following equation.

Vave = (V1 × I1 + V1 × I2) ÷
(I1 + I2) Here, Vave is the averaging speed obtained by the speed averaging processing circuit 159, V1 is the drive source side speed obtained by the speed calculation circuit 163, and V2 is obtained by the speed calculation circuit 161. The speed on the moving body side as the speed object, I1 is the moment of inertia of the drive source, and I2 is the moment of inertia of the moving body I2.

However, it is sufficient that the averaging speed can be obtained by averaging using the ratio of the dominant factors such as the moment of inertia and the like, and it is not strictly limited to the above equation. For example, a moment of inertia of an idler pulley, a belt, or the like may be added as a correction component.

As described above, by considering the moment of inertia of the driving source and the moving body, it is possible to realize accurate speed control particularly required for high image resolution in an image recording apparatus or an image reading apparatus. In a printing apparatus for printing or a large format plotter in which the moment of inertia of a driving source or a moving body is large, accurate speed control can be realized, and their functions can be fully exerted.

(Twelfth Embodiment) The speed control method based on the averaged speed information is not limited to only the PID control, and various control methods can be adopted.

[0070]

As described above, the present invention controls the moving speed of a moving body by controlling the moving speed of the moving body in consideration of the influence of power transmission means such as a belt having a predetermined spring constant. While increasing the stability of the speed,
It is possible to meet the demand for a large-sized moving body. In particular, in an image recording device or an image reading device, it is possible to realize accurate speed control required for high image resolution, and a printing recording device or a large format printing device in which a driving source or a moving body has a large moment of inertia. Accurate speed control can be realized on plotters, etc., and their functions can be fully demonstrated

[Brief description of the drawings]

FIG. 1 is a perspective view of a carriage scanning mechanism according to a first embodiment of the present invention.

FIGS. 2A and 2B are block diagrams of a control system according to the first embodiment of the present invention.

FIG. 3 is a schematic explanatory diagram of a PID operation circuit.

FIG. 4 is an explanatory diagram of a control example according to the first embodiment of the present invention.

FIG. 5 is an enlarged view at a specific time in FIG. 4;

FIG. 6 is an explanatory diagram of another control example according to the first embodiment of the present invention.

FIG. 7 is an enlarged view at a specific time in FIG. 6;

FIG. 8 is a perspective view of an ink jet recording apparatus to which the present invention can be applied.

FIG. 9 is a perspective view illustrating the internal structure of the ink jet recording apparatus of FIG.

FIG. 10 is a longitudinal sectional view of the ink jet recording apparatus of FIG.

11 is an explanatory diagram of a scanning range of a carriage in the ink jet recording apparatus of FIG.

12A, 12B, and 12C are explanatory diagrams of an ink jet cartridge that can be mounted on the ink jet recording apparatus of FIG.

13A and 13B are explanatory diagrams of a recovery system unit provided in the ink jet recording apparatus of FIG.

FIG. 14 is a block diagram of a control system of the inkjet recording apparatus of FIG. 6;

FIGS. 15A and 15B are block diagrams of a conventional control system.

16 is an explanatory diagram of a control example by the control system of FIG.

FIG. 17 is an enlarged view at a specific time in FIG. 16;

18 is an explanatory diagram of another control example by the control system of FIG.

FIG. 19 is a block diagram of another conventional control system.

FIG. 20 is an explanatory diagram of a control example by the control system of FIG. 19;

FIG. 21 is an enlarged view at a specific time in FIG. 19;

FIG. 22 is an explanatory diagram of another control example by the control system of FIG. 19;

[Explanation of symbols]

 20 Guide shaft 108 Motor driver 113 Speed controller 151 Carriage 152 Carriage motor (DC motor) 153 Driving pulley 154 Idler pulley 155 Belt 156 Linear encoder scale 157 Linear encoder sensor 158 Belt encoder sensor 159 Speed averaging circuit 161 Speed conversion circuit 162 PID operation circuit 163 Speed conversion circuit

Continued on the front page F-term (reference) 2C480 CA01 CA11 CB02 CB10 CB35 5B047 AA01 BA01 BC14 CA05 CB07 CB17 5C072 AA05 BA04 MA02 MB01 MB03 MB08 SA01 WA01 XA01 5H313 AA38 BB07 BB09 CC01 CC04 DD02 DD03 DD16 EE01 GG01 H01 KK KK16 MM01 MM02

Claims (16)

[Claims] 1. A speed control device for controlling a moving speed of a moving body which is moved by a driving force transmitted from a driving source via a power transmitting means having a predetermined spring constant, wherein First speed detecting means for detecting the moving speed of the body, second speed detecting means for detecting the moving speed of the power transmission means, and averaging the speeds detected by the first and second detecting means. A speed averaging processing means for obtaining an averaging speed; and a control means for controlling the drive source based on the averaging speed. 2. The moving speed detected by the first speed detecting means is V1, the moving speed detected by the second speed detecting means is V2, the moment of inertia of the drive source is I1, and 2. The speed control device according to claim 1, wherein when the moment of inertia is I2, the speed averaging processing means obtains the averaged speed Vave by a relational expression including at least the following expression. Vave = (V1 × I1 + V1 × I2) ÷ (I1 + I
2) 3. The speed control device according to claim 1, wherein the power transmission unit includes a belt or a wire bridged between pulleys. 4. The driving source according to claim 1, wherein the driving source is a rotational force generating source including any one of a DC motor, an ultrasonic motor, an AC motor, and a pulse motor. The speed control device according to any one of the above. 5. The speed control device according to claim 1, wherein the moving body is reciprocated by a driving force of the driving source. 6. The speed control device according to claim 5, wherein the moving body is a carriage on which a recording head capable of forming an image on a recording medium can be mounted. 7. The speed control device according to claim 5, wherein the movable body is a carriage on which a scanner capable of reading an image can be mounted. 8. The speed control device according to claim 5, wherein said first speed detection means is a linear encoder sensor. 9. The speed control device according to claim 1, wherein the second speed detection unit is an encoder sensor that reads a mark provided on the power transmission unit. 10. The driving source is a rotating force generating source for rotating a rotating shaft without intervention of a transmission, and the driving force transmitting means is driven by a driving pulley directly provided on the rotating shaft and a fixed position. The speed control device according to any one of claims 1 to 9, wherein the moving body is an endless body bridged between the pulley and the moving body, and the moving body is connected to the endless body. 11. The second detecting means is an encoder sensor provided on the power transmitting means and capable of reading a mark, and reads the mark at a position of the power transmitting means near the driving pulley. The speed control device according to claim 10, wherein: 12. The power transmission means, wherein the second detection means is an encoder sensor provided on the power transmission means and capable of reading a mark, and the mark at a position of the power transmission means wound around the drive pulley. The speed control device according to claim 10, wherein the speed control device reads out the speed. 13. A serial recording apparatus in which a moving body on which a recording head can be mounted is moved by a driving force transmitted from a driving source via a power transmission means having a predetermined spring constant. Claims 1 to 12 for controlling
A recording device comprising the speed control device according to any one of the above. 14. The recording apparatus according to claim 13, wherein said recording head is an ink jet recording head capable of discharging ink. 15. The recording apparatus according to claim 14, wherein the ink jet recording head has an electrothermal converter that generates heat energy as ink ejection energy. 16. A serial image reading apparatus for moving a movable body on which a scanner can be mounted by a driving force transmitted from a driving source via a power transmission means having a predetermined spring constant, wherein the speed of the moving body is Claims 1 to 12 for controlling
An image reading device comprising the speed control device according to any one of the above.