JP2006159696A - Recording device and method for controlling carriage drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording device which can adapt itself to load variation with time passage of years of the recording device and realize stable carriage drive control with sufficient response speed, and a method for controlling carriage drive. <P>SOLUTION: In this method for controlling carriage drive, an adjustment value of feed forward control can be determined, based on a control signal to a motor driver to be obtained during actually moving a carriage at a uniform rate, as an indication of the resultant load variation with the time passage of years of the recording device. Consequently, the adjustment value can be reflected in the following carriage scan. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording apparatus and a carriage drive control method, and more particularly, to a recording apparatus and a carriage drive control method for performing serial recording in which, for example, an inkjet recording head is mounted on a carriage.

  With the remarkable development of electronics technology, the processing power of computers has made great progress. In particular, in order to perform color image processing, a large amount of data must be processed in a short time. Conventionally, there has been a difficulty in processing speed, but in recent years, the improvement in computer capabilities has made such color image processing very common.

  Similarly, a recording apparatus for outputting a color image has been rapidly expanded in use range. Instead of conventional photographic printing, a color image is increasingly output using a recording apparatus typified by an ink jet printer. The range of use of ink jet printers is expanding from small business cards to business card sizes up to large poster sizes of B0 or larger. Further, along with the widespread use of such recording apparatuses, demands for improving the image quality and throughput of the recording apparatuses are increasing. In general, a recording apparatus performs recording while scanning a recording head with respect to a recording medium. For this reason, higher precision and higher speed are required for the carriage on which the recording head is mounted.

  In response to such a request, the recording apparatus employs a so-called servo mechanism that detects the amount of movement of the carriage with an encoder and drives the carriage according to a difference between a separately determined target movement amount and the amount of movement. ing.

  When print data is received from an external host computer, the carriage is driven by the servo mechanism, and printing is started when a predetermined scanning speed is reached. When printing of print data corresponding to one scan is completed, the carriage stops. Further, when there is recording data, carriage driving and recording are repeated.

  FIG. 11 is a typical diagram showing a carriage drive pattern accompanying the recording operation.

  According to FIG. 11, the carriage is first accelerated to a predetermined scanning speed in the acceleration section. Next, recording is executed while the carriage is driven at a predetermined scanning speed in the constant speed section. Then, the carriage is decelerated and stopped in the deceleration section after the end of recording. This drive pattern corresponds to one scan. If there is more recording data, the same driving pattern is repeated.

  The operation of the servo mechanism is to generate an appropriate driving pattern for recording and to drive the carriage so as to follow the driving pattern. If there is a malfunction, the carriage will vibrate and the recording quality on the recording medium will deteriorate.

  One of the causes of the vibration is that the mechanical natural vibration of the recording apparatus is excited by driving the carriage. It is desirable that the driving force applied to the carriage does not include a frequency band component corresponding to the natural frequency. In general, mechanical natural vibration exists in a high frequency band of a certain level or more. Therefore, it is necessary to appropriately provide a band limit for the high frequency band in the servo mechanism. Also, a structure such as a recording apparatus has a delay in force transmission due to the flexibility of the member. It is meaningless to generate a drive pattern with a wide bandwidth.

  2. Description of the Related Art Conventionally, an example in which a function for limiting a frequency band is realized in generating a drive pattern is known. A drive pattern generator is realized in which components in a frequency band higher than a desired frequency are sharply attenuated, and positions, velocities, and accelerations are differentially and integrated with each other (Patent Document 1). .

  The drive pattern is the input given to the servo mechanism, and the output corresponds to the actual position, speed, and acceleration of the carriage to be controlled. The output must follow the appropriate input. The purpose of the servomechanism is not achieved. Although various methods have been proposed so far to improve the followability, no effective technique has been found.

  As a servo mechanism for driving a structure such as a carriage, it is common to employ a feedback control system that detects the amount of movement of the carriage and sequentially updates the driving force in accordance with the deviation from the target amount of movement. It was a means. That is, the information on the speed and position of the carriage is detected, and a multiple feedback loop relating to the speed and position is formed. When a large structure such as a machine tool is assumed to be controlled, in addition to this, current feedback of an electromagnetic actuator may be configured. The target value followability of the feedback control system is determined by the loop gain of the feedback loop. If the loop gain can be set high, sufficient target value followability can be secured.

  However, it is well known that it is impossible to set the loop gain too high. Causes are classified into mechanical factors, electrical factors, and computer capability factors. Of these, the mechanical influence is the most significant. That is, the resonance point of the structure makes the feedback loop unstable. In order not to excite the resonance point, the loop gain must be set low. For this reason, the use of a notch filter in the feedback loop has been widely studied, but is applicable only when the resonance frequency is always constant. Since it is considered that the resonance frequency varies due to a manufacturing problem, it is not practical to employ a notch filter in a recording apparatus premised on mass production.

  As an electrical factor, a current delay due to the inductance of the electromagnetic actuator is known. There is also an element delay in the drive circuit. The sampling period of the control system is limited by the processing speed of the computer. If the sampling period cannot be set sufficiently short with respect to the responsiveness required for the control system, a phase delay due to intermittent sampling occurs. This causes performance degradation of the feedback loop.

  For the recording apparatus under consideration here, from the viewpoint of power saving and space saving, a one-chip microcomputer is usually adopted as the control unit. Considering the processing power of the microcomputer, the influence of the sampling period cannot be ignored.

Furthermore, there is a limit to the target value followability if only the performance of the feedback control system is relied upon. For this reason, feedforward control has been proposed in which the driving force is determined in anticipation of the operation of the controlled object. This is because the feedback control is a reflection action according to the deviation signal, whereas the feedforward control is a foreseeing action, and the effect of the feedforward control is enormous if the characteristics of the controlled object can be accurately grasped. If the feedforward control operates as designed, it is possible to completely match the target drive pattern with the operation to be controlled.
JP-A-8-286761 (FIG. 1)

  However, in the servo mechanism for the carriage of the printing apparatus, there are two barriers described below for effective feedforward control.

  For one thing, the dynamic characteristics of the carriage must be properly captured. It is necessary to properly capture the dynamic characteristics of the servo mechanism and actuator. In the recording apparatus, a DC motor or a DC brushless motor is employed as an actuator for driving the carriage. Such a motor generates a counter electromotive force proportional to the rotational speed. The influence of back electromotive force on dynamic characteristics cannot be ignored.

  Second, the load changes over time. In order to convert the rotational movement of the motor into the translational movement of the carriage, the carriage is driven by a belt suspension. A predetermined initial tension is applied to the belt, and the belt is suspended on the carriage and the motor without being loosened. However, since the belt is a flexible member, a variation in tension occurs over time. For the servo mechanism, belt tension fluctuation is equivalent to load fluctuation. Further, the carriage is driven in the translation direction by the guide shaft. There is a slight backlash between the carriage and the guide shaft. In order to remove looseness, the carriage is often applied with a pressing force against the guide shaft. This is realized by using a coil spring or the like, but it goes without saying that aging also occurs.

  In the ink jet recording apparatus, it is inevitable that ink adheres to the carriage drive system during the recording operation. Most of the ink ejected from the ink jet recording head (hereinafter, recording head) adheres to the recording medium, but a small amount of ink is sprayed in a mist and adheres to a mechanism such as a guide shaft. The carriage running resistance increases with ink adhesion. Therefore, the load increases with time with the operation of the recording apparatus. Thus, since the presence of load fluctuation cannot be ignored in the recording apparatus, it has been difficult to properly operate the feedforward control system over time.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is a recording apparatus and a carriage drive control method that realizes stable carriage drive control with sufficient response speed and adapting to a change in load of the recording apparatus over time. And is intended to provide.

  In order to achieve the above object, the recording apparatus of the present invention has the following configuration.

  That is, a recording apparatus for performing recording on a recording medium by reciprocating a carriage having a recording head by a driving force of a carriage motor, and detecting a motor driver for driving the carriage motor and a position and a speed of the carriage. Detecting means for driving, a drive instructing means for giving a drive command to the carriage, a drive command by the drive instructing means, and a carriage position and a carriage speed detected by the detecting means to drive the carriage. A feedback control unit that performs feedback control via a driver, a feed that adjusts a control signal to the motor driver based on a control signal from the feedback control unit to the motor driver and a drive command from the drive instruction unit. Forward control means. The forward-forward control means holds a control signal to the motor driver at a predetermined sampling period during the constant speed movement period of the carriage, and an adjustment value of the control signal to the motor driver during the deceleration movement period of the carriage. And the adjustment value is reflected in the next carriage scan during the carriage stop period following the deceleration movement period.

  The drive command includes a carriage position command, a speed command, and an acceleration command.

  The feedforward control means receives a carriage acceleration command, integrates the proportional and integral filter circuit, the carriage speed command, a control signal to the motor driver, and an output from the proportional and integral filter circuit. And an adjusting circuit for adjusting the integral gain of the proportional and integral filter circuit.

  In this case, in the adjustment circuit, the difference between the control signal to the motor driver obtained at a predetermined sampling period during the constant speed movement period of the carriage and the output from the proportional and integral filter circuit is minimal. It is preferable to adjust the integral gain during the carriage deceleration movement period.

  As another configuration, the feedforward control means includes a first proportional gain circuit for inputting a carriage acceleration command, a second proportional gain circuit for inputting a carriage speed command, a carriage speed command, and a motor. An adjustment circuit for adjusting the gain of the second proportional gain circuit by inputting a control signal to the driver and an output from the second proportional gain circuit may be provided.

  The recording head may be an ink jet recording head that performs recording by discharging ink, and the ink jet recording head uses electric energy to generate thermal energy to be applied to the ink in order to discharge ink using thermal energy. More preferably, a converter is provided.

  According to another invention, there is provided a carriage drive control method used in a recording apparatus for recording on a recording medium by reciprocating a carriage having a recording head by a driving force of a carriage motor, wherein the drive command is sent to the carriage. A driving instruction process for detecting the position and speed of the carriage, a driving command in the driving instruction process, and the carriage position and carriage speed detected in the detection process. A feedback control step for feedback control via a motor driver for driving the carriage motor; a control signal to the motor driver in the feedback control step; and a drive command in the drive instruction step. Adjust the control signal of the feed The feedforward control step holds a control signal to the motor driver at a predetermined sampling period during the constant speed movement period of the carriage, and during the deceleration movement period of the carriage, An adjustment value of a control signal to the motor driver is calculated, and the adjustment value is reflected in the next carriage scan during the carriage stop period following the deceleration movement period. A control method is provided.

  Therefore, according to the present invention, the adjustment value in the feedforward control is obtained based on the control signal to the motor driver obtained during the actual carriage movement at the constant speed, which is the result of the load fluctuation with time of the printing apparatus. Therefore, it is possible to realize stable carriage drive control that has a sufficient response speed and that takes into consideration the influence of aged load fluctuations in near real time.

  Hereinafter, preferred embodiments of the present invention will be described more specifically and in detail with reference to the accompanying drawings.

  In this specification, “recording” (sometimes referred to as “printing”) is not only for forming significant information such as characters and figures, but also for human beings visually perceived regardless of significance. Regardless of whether or not it has been manifested, it also represents a case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or the medium is processed.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Furthermore, “ink” (sometimes referred to as “liquid”) is to be interpreted broadly in the same way as the definition of “recording (printing)” above. It represents a liquid that can be used for forming a pattern or the like, processing a recording medium, or processing an ink (for example, solidification or insolubilization of a colorant in ink applied to the recording medium).

  Furthermore, unless otherwise specified, the “nozzle” collectively refers to an ejection port or a liquid channel communicating with the ejection port and an element that generates energy used for ink ejection.

<Description of Inkjet Recording Apparatus (FIG. 1)>
FIG. 1 is an external perspective view showing an outline of the configuration of an ink jet recording apparatus which is a typical embodiment of the present invention. FIG. 1 pays particular attention to the carriage 1 and the mechanism for driving the carriage 1.

  As shown in FIG. 1, a carriage 1 on which an ink jet recording head is mounted is guided by two guide shafts 2 and reciprocates in the direction of arrow A. The belt 3 is fixed to the carriage 1 via a belt holder 4. The belt 3 is suspended by the pulley 6 and the idle pulley 7 without slack. The pulley 6 and the idle pulley 7 are respectively disposed at both ends of the carriage 1 in the scanning direction. A carriage motor 5 as an actuator is connected to the pulley 6. The driving force generated by the carriage motor 5 is transmitted as a thrust to the carriage 1 through the pulley 6, the idle pulley 7 and the belt 3.

  That is, the rotational movement of the carriage motor 5 is converted into the translational movement of the carriage 1 through these mechanisms. The scale 8 is provided along the movement direction of the carriage in order to detect the movement amount of the carriage 1 in the scanning direction, and slits are provided at equal intervals. The carriage 1 is provided with an encoder 8a so that the position of the carriage 1 can be detected by reading the slits of the scale 8.

  Note that the carriage 1 of the recording apparatus of this embodiment is configured such that the recording head and the ink cartridge for storing ink are separately mounted in a separable configuration. However, the recording head and the ink cartridge are integrated. The head cartridge thus formed may be mounted on the carriage 1.

<Control Configuration of Inkjet Recording Apparatus (FIG. 2)>
FIG. 2 is a block diagram showing a control configuration of the recording apparatus shown in FIG.

  As shown in FIG. 2, the controller 600 includes an MPU 601, a program corresponding to a control sequence to be described later, a required table, a ROM 602 storing other fixed data, control of the carriage motor 5, control of the transport motor M2, and recording. A special purpose integrated circuit (ASIC) 603 that generates a control signal for controlling the head 3, and a RAM 604, an MPU 601, an ASIC 603, and a RAM 604, which are provided with image data development areas and program execution areas, are connected to each other. A system bus 605 for transferring data, and an A / D converter 606 for inputting analog signals from the sensor group described below, A / D converting them, and supplying digital signals to the MPU 601 and the like.

  In FIG. 2, reference numeral 610 denotes a computer (or a reader for image reading, a digital camera, etc.) serving as a supply source of image data, and is collectively referred to as a host device. Image data, commands, status signals, and the like are transmitted and received between the host apparatus 610 and the recording apparatus 1 via an interface (I / F) 611.

  Further, reference numeral 620 denotes a switch group, which instructs activation of a power switch 621, a print switch 622 for instructing printing start, and a process (recovery process) for maintaining the ink ejection performance of the recording head 3 in a good state. For example, a recovery switch 623 for receiving a command input from the operator. Reference numeral 630 denotes a position sensor 631 such as a photocoupler for detecting the home position h, a temperature sensor 632 provided at an appropriate location of the recording apparatus for detecting the environmental temperature, and the like. It is a sensor group.

  Further, 15 is a carriage motor driver for driving the carriage motor 5 for reciprocating scanning of the carriage 1 in the direction of arrow A, and 642 is a transport motor driver for driving the transport motor M2 for transporting the recording medium P. The carriage motor driver 15 is controlled by the servo mechanism 640 based on an output signal from the encoder 8a.

  The ASIC 603 transfers drive data (DATA) of the recording element (heater) to the recording head while directly accessing the storage area of the RAM 602 during recording scanning by the recording head 3.

  Hereinafter, an embodiment of carriage control of the recording apparatus having the above configuration will be described.

  FIG. 3 is a block diagram showing a servo mechanism 640 of the carriage according to the first embodiment of the present invention.

  In order to scan the carriage 1 with respect to the recording medium, information on the position and speed of the carriage 1 is required. This position and velocity are extracted based on the signal from the encoder 8a. The speed detector 13 generates speed information from the output of the encoder 8a. The operation is known, and for example, the time width of the pulse train output from the encoder 8a is measured, or the amount of change per unit time of the pulse train is calculated. The position detector 14 is also well known, and information on the carriage position is obtained by counting the pulse train output by the encoder 8a.

  The drive pattern generator 9 outputs a time axis profile when the carriage 1 scans the recording medium in the form of a position command value, a speed command value, and an acceleration command value. These values have a relationship of differentiation and integration with each other. The position information output from the position detector 14 is compared and subtracted from the position command value output from the drive pattern generator 9 and guided to the position compensator 10. On the other hand, the speed compensator 11 generates a compensation value by deriving the speed output from the speed detector 13, the speed command value generated by the drive pattern generator 9, and the output signal of the position compensator. Such a double loop of position and speed is a conventional means of a servo mechanism. Normally, the position compensator 10 performs a proportional operation, and the speed compensator 11 performs a proportional + integral operation.

  The acceleration command value generated by the drive pattern generator 9 is added to the output of the speed compensator 11 after passing through the filter 12 to form a control input. The control input is an input signal given to the carriage motor driver 15. The carriage motor driver 15 performs power amplification of the control input. When a voltage proportional to the control input is applied to the carriage motor 5, a driving torque for driving the carriage 1 is generated. This driving torque is converted into a driving force for driving the carriage 1 in the scanning direction via a mechanism such as the belt 3.

  A transmission path that becomes a control input from the acceleration command value via the filter 12 corresponds to a so-called feedforward control system. If the filter 12 is appropriately designed, the acceleration generated in the carriage 1 can be made exactly the same as the acceleration command value. In order to design the filter 12, the dynamic characteristics of the carriage 1 with respect to the control input must be analyzed. In this embodiment, the dynamic characteristics are analyzed separately for an electric system and a mechanical system.

  FIG. 4 is a model diagram showing electrical dynamic characteristics of the carriage motor driver 15 and the carriage motor 5.

  FIG. 5 is a model diagram showing mechanical dynamic characteristics of the mechanism including the carriage 1.

  The symbols used in FIGS. 4 to 5 are as follows.

s: Laplace operator θ: rotation angle of carriage motor 5 [rad]
u: Control input E: Voltage applied to carriage motor 5 [V]
Kc: conversion coefficient from control input to applied voltage to carriage motor 5 [V]
R: DC resistance of coil [Ω]
L: Coil inductance [H]
i: Motor current [A] flowing through the carriage motor 5
Kt: Torque constant of carriage motor 5 [Nm / A]
τ: Torque generated by carriage motor 5 [Nm]
r: radius of pulley 6 [m]
J: Moment of inertia of rotary motion system [kg.m ² ]
D: Viscous resistance of rotational motion system [Nm / (rad / s)]
M: Mass of carriage 1 [kg]
C: Viscous resistance of translational motion system [N / (m / s)]
In FIG. 4, the applied voltage (E) to the carriage motor 5 is proportional to the control input (u). Both are connected by Formula (1). The electrical characteristics of the carriage motor 5 are expressed by a counter electromotive force proportional to the DC resistance (R) of the coil, the inductance (L) of the coil, and the rotational angular velocity (sθ) of the carriage motor 5. The relationship between the control input and the motor current (i) is expressed by Equation (2) Expression (2) indicates that the motor current is determined by the impedance of the carriage motor 5 and the counter electromotive force with respect to the control input.

E = Kc · u (1)
(Ls + R) i + Kt.s.theta. = Kc.u (2)
In FIG. 5, the carriage 1 is pulled by the pulley 6 through the belt 3. The tension of the belt 3 becomes a load for the rotational movement of the pulley 6. This is modeled as viscous resistance (D) for a rotational motion system. On the other hand, the pressing force applied to the carriage 1 for backlash removal and the running resistance due to ink adhesion are expressed as a load on the translational movement of the carriage 1. This is modeled as a viscous resistance (C) of a translational motion system. The relationship between the generated torque τ of the carriage motor 5 and the acceleration s ² x generated in the carriage 1 at that time is expressed by Expression (3).

{(M + J / r ² ) s + (C + D / r ² )} s ² x = sτ (3)
The generated torque of the carriage motor 5 is proportional to the motor current as shown in the equation (4). From the above, the transfer function from the control input to the acceleration of the carriage 1 is expressed by Expression (5).

    τ = Kt · i (4)

...... (5)
Therefore, Expression (5) is an analysis result of the dynamic characteristics of the carriage 1 as seen from the control input. The filter 12 may be designed based on this.

  In order to make the acceleration command value generated by the drive pattern generator 9 coincide with the acceleration of the carriage 1 generated at this time, the inverse system of the transfer function expressed by the equation (5) may be realized by the filter 12. However, since the delay due to the inductance (L) is small, it is ignored. Assuming that the transfer function of the filter 12 is G, the transfer function (G) is expressed as in Expression (6). As can be seen from the equation (6), the filter 12 has a proportional + integral filter configuration.

(6)
FIG. 6 is a block diagram showing the configuration of the filter 12.

As shown in FIG. 6, the filter 12 applies an integrator 19 and an integral gain 20 corresponding to the break frequency of the (proportional + integral) filter to the acceleration command value, and then adds it to the acceleration command value. Finally, the filter gain 18 is multiplied. The integral gain 20 and the filter gain 18 are uniquely determined from the analysis result of Expression (6). Focusing on the integral term including (1 / s) in equation (6), C and D indicate the influence of the mechanical load, and Kt ² / R carriage indicates the influence of the back electromotive force of the motor 5. Show.

  FIG. 7 is a diagram of simulation results showing the effectiveness of the first embodiment. In FIG. 7, the followability of the speed of the carriage 1 with respect to the speed command value is shown in the acceleration section and the constant speed section.

  FIG. 7A shows a simulation result when the feed-forward control is not performed with the filter gain 18 set to zero. In FIG. 7A, the broken line indicates the speed command value, and the solid line indicates the speed of the carriage 1. As shown in FIG. 7A, in the acceleration section, the speed rise is obviously slower than the speed command value. Even after entering the constant velocity section, the deviation from the speed command value remains. This leads to recording during the acceleration period, leading to a decrease in recording quality. If the gains of the speed compensator 11 and the position compensator 10 can be set to be sufficiently large, it is possible to ensure the required responsiveness with only the feedback control system, but this is not realistic. This is because the loop gain of the feedback loop is limited to such an extent that the resonance point of the mechanism is not excited.

  FIG. 7B shows a simulation result when the integrator 19 is removed from the filter 12. Excluding the integrator 19 is equivalent to the case where the integral gain 20 is set to zero. As shown in FIG. 7B, the speed rise improves, but a deviation from the speed command value remains in the constant speed section.

  FIG. 7C shows a simulation result when the filter 12 is appropriately set as a (proportional + integral) filter in response to the analysis result shown in the equation (6). The response of the carriage 1 almost coincides with the speed command value. The simulation results show that when the filter 12 is appropriately set as a (proportional + integral) filter, the followability of the actual speed with respect to the speed command value is greatly improved, and the effectiveness of this embodiment is clear. Is shown.

  Returning to FIG. 3, this embodiment will be further described.

  The regulator 16 operates to properly adjust the filter 12 in response to mechanical load fluctuations. In the servo mechanism of the carriage 1 in this embodiment, the response of the carriage 1 is extremely stable because the filter 12 is appropriately adjusted by the operation of the adjuster 16 even if a load change occurs.

  FIG. 8 is a block diagram showing the relationship between the filter 12 and the regulator 16.

  As shown in FIG. 8, the adjuster 16 sends to the integrator 19 of the filter 12 according to the control input guided to the carriage motor driver 15, the speed command value output from the drive pattern generator 9, and the output of the filter 12. The integral gain 20 is adjusted. As already described in the background art, there is a secular change in the load of the rotational motion system due to the belt tension and the load of the translational motion system due to ink adhesion. According to the analysis result shown in Expression (6), the parameters C and D indicating the load fluctuation depend on the integral term including (1 / s). Therefore, if the integral gain 20 of the filter 12 is appropriately adjusted according to the load fluctuation, the operation of the servo mechanism becomes extremely stable.

  In order to detect the load fluctuation, it is only necessary to record a control input given to the carriage motor driver 15 in a constant speed section when the carriage 1 is scanned. This is because the input of the filter 12 is an acceleration command value output from the drive pattern generator 9, and the term including (1 / s) in the expression (6) showing the transfer function of the filter 12 is 1 of the acceleration command value. It can also be said that it indicates a coefficient applied to the speed command value by the step integration. In the constant speed section, the acceleration command value is zero, whereas the speed command value is a constant value equal to a predetermined scanning speed. Therefore, it is a component by the integrator 19 and the integral gain 20 that determines the output of the filter 12 in the constant velocity section.

  From the above examination, it can be seen that the integral gain 20 may be adjusted according to the control input in the constant speed section. Therefore, it is only necessary to adjust the integral gain 20 in a direction that reduces the difference between the control input and the output of the filter 12 in the constant speed section.

  FIG. 9 is a diagram showing the operation sequence of the regulator 16 in time series.

  First, in the constant speed movement section of the carriage, as processing 1, when the speed command value coincides with a predetermined scanning speed, it is determined that the driving state of the carriage 1 is in the constant speed section. As the process 2, the output of the filter 12 and the control input given to the motor driver 15 are recorded for each sampling period of the servo mechanism.

  Next, in the deceleration movement section of the carriage, as processing 3, it is determined from the speed command value that the driving state of the carriage 1 is in the deceleration section. As a process 4, an appropriate integral gain 20 in the filter 12 is calculated and held so as to minimize the difference between the recorded output of the filter 12 and the control input. At this stage, the integral gain 20 is only retained and not updated. This is because if the update is performed while the carriage 1 is driven, vibration may occur in the carriage 1 at the update timing. As the process 5, once the update value of the integral gain 20 is calculated, the process in the deceleration zone is finished.

  Since there is a short stop period (stop period) before moving to the next scan, the value of the integral gain 20 is updated as processing 6 in the stop period.

  Therefore, according to the embodiment described above, the output of the filter 12 and the control input given to the motor driver 15 are stored in the storage means (memory) for each sampling period of the servo mechanism in the constant speed movement section of the carriage, and the carriage Is entered in the deceleration movement section, the calculation to obtain the updated value of the integral gain is performed, and the value of the integral gain is updated in the carriage stop section before moving to the next carriage scan. The adjustment value of the integral gain can be reflected in the next scan. As a result, load fluctuations related to the aging of the carriage drive system can be reflected in the carriage drive control almost in real time, and stable carriage drive can be realized.

  As described in the first embodiment, if a (proportional + integral) filter is applied to the acceleration command value output from the drive pattern generator 9 to provide a control input to the motor driver 15, the movement of the carriage 1 is controlled. The command value could be the same.

  By the way, applying the acceleration command value to the integrator 19 and the integration gain 20 is substantially equivalent to applying the integration gain 20 to the speed command value that is the first order integral of the acceleration command value. The drive pattern generator 9 outputs an acceleration command value and a speed command value that are in a differential and integral relationship with each other.

  Therefore, a servo mechanism using a proportional gain instead of the filter 12 may be configured in consideration of the above relationship.

  FIG. 10 is a block diagram showing the configuration of the servo mechanism according to the second embodiment of the present invention.

  In FIG. 10, the same components as those already described with reference to FIG.

  In the configuration shown in FIG. 10, the proportional gain 17a is applied to the acceleration command value, and at the same time, the proportional gain 17v is applied to the speed command value, and both are added to form a contribution to the control input.

  Accordingly, in the first embodiment, a filter that considers only the acceleration command value is used. However, since the speed command value is also considered in the servo mechanism of this embodiment, the time for time integration is not required, and the operation of the carriage 1 is desired. Target value followability can be provided.

  The adjuster 16 appropriately adjusts the proportional gain 17v applied to the speed command value in accordance with the control input, the speed command value, and the output of the proportional gain 17v. The operation of the adjuster 16 is the same as that in the first embodiment, and the response of the carriage 1 becomes extremely stable even if a load change occurs.

  In the first and second embodiments, the operation of the adjuster 16 has been described for the case where the proportional gain 17v or the integral gain 20 of the filter 12 is adjusted in accordance with the control input and the speed command value. However, the present invention is limited to this. Is not to be done. For example, in order to determine whether the driving state of the carriage 1 is in the acceleration section, the constant speed section, or the deceleration section, the speed command value is used in the first and second embodiments, but the acceleration command value is used. However, the same determination can be made, and the speed of the carriage 1 may be used.

  Further, the proportional gain 17 a or the filter gain 18 of the filter 12 may be adjusted by the action of the adjuster 16. Thereby, the target value followability of the carriage 1 can be further improved.

  Further, in the embodiment described above, the adjuster is operated in one scan and the updated value is reflected in the next scan. However, such adjustment is executed in each scan in this way. Alternatively, for example, it may be executed at a rate of once for a plurality of scans. The calculation of the integral gain may be performed during the stop period as long as the stop period has a sufficient length.

  In any case, as described above, in these embodiments, the feedforward control considering the influence of the mechanical load and the influence of the back electromotive force of the motor, which greatly influences the dynamic characteristics of the carriage, is performed. Introducing into the mechanism, for example, to improve the target value tracking performance of the servo mechanism stably and with high durability regardless of changes in load such as belt tension and ink adhesion to the guide shaft. Can do. The controller 600 may also serve as the servo mechanism 640. That is, the controller 600 may input a signal from the encoder 8 a and output a control signal to the carriage motor driver 15.

  Furthermore, in the above embodiments, the liquid droplets ejected from the recording head have been described as ink, and the liquid stored in the ink tank has been described as ink. However, the storage is limited to ink. It is not a thing. For example, a treatment liquid discharged to the recording medium may be accommodated in the ink tank in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

  The above embodiment includes means (for example, an electrothermal converter or a laser beam) that generates thermal energy as energy used to perform ink ejection, particularly in the ink jet recording system, and the ink is generated by the thermal energy. By using a system that causes a change in the state of recording, it is possible to achieve higher recording density and higher definition.

  In the above embodiments, the serial scan type ink jet recording apparatus has been described as an example. However, the present invention is not limited to this, and the present invention is also effective for recording apparatuses employing other recording methods, for example, a thermal transfer recording method. Applicable to.

  In addition, even the serial scan type as in the above-described embodiments is mounted on the recording head fixed to the apparatus main body or the apparatus main body so that the electrical connection with the apparatus main body and the ink from the apparatus main body The present invention is also effective when an exchangeable cartridge type recording head that can be supplied is used.

  In addition, the ink jet recording apparatus according to the present invention may be used as an image output apparatus for information processing equipment such as a computer, a copying apparatus combined with a reader, or a facsimile apparatus having a transmission / reception function. It may be one taken.

1 is a perspective view showing a configuration of an ink jet recording apparatus that is a typical embodiment of the present invention. FIG. 2 is a block diagram illustrating a control configuration of the recording apparatus illustrated in FIG. 1. It is the block diagram which showed the servo mechanism 640 of the carriage according to Example 1 of this invention. 3 is a model diagram showing electrical dynamic characteristics of a carriage motor driver 15 and a carriage motor 5. FIG. 3 is a model diagram showing mechanical dynamic characteristics of a mechanism including a carriage 1. FIG. 3 is a block diagram showing a configuration of a filter 12. FIG. It is a figure of the simulation result which shows the effectiveness of Example 1. FIG. 3 is a block diagram showing a relationship between a filter 12 and a regulator 16. FIG. It is the figure which showed the operation | movement sequence of the regulator 16 in time series. It is the block diagram which showed the servo mechanism 640 of the carriage according to Example 2 of this invention. FIG. 6 is a typical diagram illustrating a carriage drive pattern accompanying a recording operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carriage 2 Guide shaft 3 Timing belt 4 Belt holder 5 Carriage motor 6 Pulley 7 Idle pulley 8 Scale 8a Encoder 9 Drive pattern generator 10 Position compensator 11 Speed compensator 12 Filter 13 Speed detector 14 Position detector 15 Carriage motor driver 16 regulators 17a, 17v proportional gain 18 filter gain 19 integrator 20 integral gain

Claims (8)

A recording apparatus for recording on a recording medium by reciprocating a carriage mounted with a recording head by a driving force of a carriage motor,
A motor driver for driving the carriage motor;
Detecting means for detecting the position and speed of the carriage;
Drive instruction means for giving a drive command to the carriage;
Feedback control means for feedback-controlling driving of the carriage via the motor driver based on a drive command from the drive instruction means and a carriage position and carriage speed detected by the detection means;
A feedforward control means for adjusting a control signal to the motor driver based on a control signal from the feedback control means to the motor driver and a drive command from the drive instruction means;
The feedforward control means includes
During a constant speed movement period of the carriage, a control signal to the motor driver is held at a predetermined sampling period,
During the deceleration movement period of the carriage, the adjustment value of the control signal to the motor driver is calculated,
The recording apparatus, wherein the adjustment value is reflected in the next carriage scan during the carriage stop period following the deceleration movement period.   The recording apparatus according to claim 1, wherein the drive command includes a position command, a speed command, and an acceleration command of the carriage. The feedforward control means includes
A proportional and integral filter circuit for integrating by inputting the acceleration command of the carriage;
And an adjustment circuit for adjusting an integral gain of the proportional and integral filter circuit by inputting a speed command of the carriage, a control signal to the motor driver, and an output from the proportional and integral filter circuit. The recording apparatus according to claim 1 or 2.   In the adjustment circuit, the difference between the control signal to the motor driver obtained at a predetermined sampling period during the constant speed movement period of the carriage and the output from the proportional and integral filter circuit is minimal. The recording apparatus according to claim 3, wherein the integral gain is adjusted during a carriage deceleration movement period. The feedforward control means includes
A first proportional gain circuit for inputting an acceleration command of the carriage;
A second proportional gain circuit for inputting a speed command of the carriage;
An adjustment circuit for adjusting a gain of the second proportional gain circuit by inputting a speed command of the carriage, a control signal to the motor driver, and an output from the second proportional gain circuit; The recording apparatus according to claim 1 or 2.   The recording apparatus according to claim 1, wherein the recording head is an ink jet recording head that performs recording by discharging ink. The recording head according to claim 6, wherein the inkjet recording head includes an electrothermal transducer for generating thermal energy to be applied to the ink in order to eject the ink using thermal energy. . A carriage drive control method used in a recording apparatus for recording on a recording medium by reciprocating a carriage mounted with a recording head by a driving force of a carriage motor,
A drive instruction step for giving a drive command to the carriage;
A detection step of detecting the position and speed of the carriage;
A feedback control step of feedback-controlling the drive of the carriage based on the drive command in the drive instruction step and the carriage position and carriage speed detected in the detection step via a motor driver for driving the carriage motor;
A feedforward control step of adjusting a control signal to the motor driver based on a control signal to the motor driver in the feedback control step and a drive command in the drive instruction step;
The feedforward control step includes
During a constant speed movement period of the carriage, a control signal to the motor driver is held at a predetermined sampling period,
During the deceleration movement period of the carriage, the adjustment value of the control signal to the motor driver is calculated,
The carriage drive control method, wherein the adjustment value is reflected in the next carriage scan during the carriage stop period following the deceleration movement period.

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