JP5125370B2 - Drive control device and drive control method - Google Patents

Description

  The present invention relates to a drive control apparatus and a drive control method for controlling an electric motor that drives a driven body based on a speed difference between a fed back actual speed and a predetermined target speed.

  2. Description of the Related Art Conventionally, an ink jet recording type image recording apparatus that records an image on a recording sheet by attaching ink droplets to the recording sheet is known. This type of image recording apparatus is provided with a carriage (driven body) on which a recording head is mounted. The carriage is connected to a motor (electric motor) via a transmission gear, and reciprocates in a predetermined direction by receiving the driving force of the motor.

  In the image recording apparatus, the carriage is affected by disturbance factors such as the eccentricity of the motor shaft and the cogging torque of the motor. For example, when influenced by the cogging torque of the motor that is periodically generated during the movement of the carriage, as shown in FIG. descend. FIG. 12 is a graph showing the speed characteristics (speed change) of the carriage when affected by the cogging torque. In addition, the broken line in a figure shows a target speed profile.

The carriage speed fluctuation due to the disturbance element is applied to the conventional feedback control system 200 (see FIG. 13) in which the gain (amplification factor) in the drive control device (motor driver) for driving and controlling the motor is set to a high value. This can be suppressed. FIG. 13 is a block diagram showing the configuration of the conventional feedback control system 200. As shown in FIG. In the feedback control system 200 shown in FIG. 13, a predetermined target speed V _ref and a target acceleration A _ref calculated from the target speed V _ref so as to follow the target speed V _ref are input, and the plant 202 (the control target) For example, the actual speed (actual speed) _Vout of the plant 202 when the carriage is driven is expressed by the following equation (C), where the gain of the driver 201 is C, the loss of the plant 202 is P, and the loss due to the disturbance element is τ. It is expressed as 1). Note that “s” in equation (1) is a differential symbol by Laplace transform. According to the right side of equation (1), when gain C is increased, the coefficient of loss τ due to the disturbance element (the coefficient of the second term) converges to “0”, and the coefficient of target speed V _ref (the coefficient of the first term) ) Converges to “1”, the actual speed V _out is hardly affected by the disturbance element, and is approximated to the target speed V _ref .

  By the way, when the carriage is stopped in the image recording apparatus, a static frictional force acts on the carriage. For this reason, even if a driving current is output to the motor, the carriage does not start until the driving force of the motor exceeds the static frictional force. For example, when the target speed is set so that the speed increases with the passage of time, the actual speed (actual speed = 0 [m / s]) and the target speed increase. At this time, since the drive current in which the gain is added to the speed difference is output to the motor, the drive current also increases. In particular, when the conventional feedback control system 200 (see FIG. 13) in which the gain is set to a high value in order to suppress the influence of the disturbance element as described above is applied, an excessive drive current is output to the motor, and the carriage Excessive torque is applied to the. Therefore, immediately after the carriage starts to move, the actual speed greatly overshoots the target speed, and the actual speed fluctuates with respect to the target speed as shown in FIG. FIG. 14 is a graph showing the carriage speed characteristics (speed transition) when the conventional feedback control system 200 is applied. In addition, the broken line in a figure shows a target speed profile.

  In Patent Documents 1 to 3, in consideration of the phenomenon that a static frictional force acts and does not start when the carriage starts to be driven, the actual speed overshoot with respect to the target speed is reduced, and A control method for improving the followability of the actual speed is described. For example, Patent Document 1 uses a profile of a target speed that changes with the passage of time, in which the target speed at the start of the motor is set to a predetermined value that is greater than zero. Speed change is prevented.

JP 2007-28808 A JP 2000-71541 A JP 2005-86941 A

  However, in the control methods described in the above-mentioned patent documents, even if the overshoot at the time of starting the carriage can be reduced and the followability of the actual speed can be improved, the eccentricity of the motor shaft, the cogging torque of the motor, etc. The fluctuation of the carriage speed due to the disturbance element cannot be eliminated. Of course, the speed fluctuation due to the influence of the disturbance element is not limited to the carriage of the image recording apparatus, but may occur in various driven bodies driven by a motor.

  Therefore, the present invention has been made in view of the above circumstances, and the first object thereof is to reduce the overshoot when the driven body is started up and improve the follow-up performance of the actual speed. Another object of the present invention is to provide a drive control device and a drive control method capable of reducing fluctuations in the speed of the driven body due to disturbance factors such as eccentricity of the motor shaft and cogging torque of the motor.

  The second object of the present invention is to reduce the time required for the stopped carriage to move, and to reduce overshoot after the carriage starts to move, and drive control. It is to provide a method.

(1) The present invention is a drive control device that controls an electric motor that drives a driven body based on a speed difference between a fed back actual speed and a predetermined target speed. The drive control device includes a storage unit, a first determination unit, and a first generation unit. The storage means stores a first amplification factor for amplifying a control value used for controlling the electric motor and a second amplification factor larger than the first amplification factor. The first determination means is during acceleration control of the driven body, and is during the acceleration control after a lapse of time from when the acceleration control is started until the speed difference becomes larger than a predetermined threshold value . It is determined whether the speed difference is equal to or less than a predetermined threshold value. The first generation means uses the first amplification factor to perform the first control according to the speed difference until the first determination means determines that the speed difference is equal to or less than a predetermined threshold. A second control value corresponding to the speed difference using the second amplification factor is generated in the second section after the first determination means determines that the speed difference is less than or equal to a predetermined threshold. Is generated.

  With this configuration, the drive control device of the present invention determines whether the speed difference is equal to or smaller than a predetermined threshold value by the first determination unit during acceleration control, and the speed difference is determined to be a predetermined threshold value. In the first interval until it is determined as follows, the first generation means generates the first control value corresponding to the speed difference using the first amplification factor. The second section after the speed difference is determined to be less than or equal to a predetermined threshold by the first determination means is calculated using the second amplification factor that is higher than the first amplification factor by the first generation means. A second control value corresponding to the speed difference is generated. Thereby, since the electric motor is controlled using the first control value generated at the first amplification factor in the first section, the first control value does not become excessive even if the speed difference is large. Therefore, the actual speed does not greatly exceed the target speed. Therefore, the actual speed of the driven body does not fluctuate in vibration, and the control of the electric motor is stabilized. In the second section, since the electric motor is controlled using the second control value generated at the second amplification factor larger than the first amplification factor, the driven body can be the eccentricity of the shaft of the electric motor or the cogging torque. Drives stably without being affected by disturbance factors such as In addition, since the control using the second control value is started when the speed difference becomes equal to or less than the predetermined threshold value, the actual speed does not fluctuate greatly in the second section.

(2) The drive control device according to the present invention includes a second determination unit that determines whether or not the driven body has started moving from a stopped state, and a period until the second determination unit determines that the driven body has started to move. The third section further includes second generation means for generating a third control value by adding a predetermined auxiliary control value to the first control value.

  If the amplification factor when the driven body starts to move is too low, the first control value is small. Therefore, it takes time for the stopped carriage to start moving, and thus it takes a considerable time for the carriage to reach the final target speed. . However, in the drive control device according to the present invention, in the third section until the second determining means determines that the driven body has started to move, the electric motor using the third control value generated by the second generating means. Is controlled. For this reason, the carriage starts to move quickly. Further, since the electric motor is controlled using the first control value after the carriage starts to move, the overshoot of the actual speed with respect to the target speed is reduced.

(3) The drive control device of the present invention further includes first control means for controlling the motor by outputting a drive current corresponding to either the first control value or the second control value to the motor. It is desirable to provide.

(4) Further, the drive control device of the present invention controls the motor by outputting a drive current corresponding to any of the first control value, the second control value, or the third control value to the motor. A second control means may be further provided.

(5) The driven body includes a carriage mounted with a recording head in an image recording apparatus of an ink jet recording system and capable of reciprocating in a direction crossing the transport direction of the recording medium, or a plurality of image reading in the image reading apparatus. It is preferable that the carriage is mounted on an element and can reciprocate in a direction intersecting with the arrangement direction of the image reading elements.

(6) The driven body may be a conveyance roller for conveying a recording medium in a thermal image recording apparatus or a conveyance roller for conveying a document in an automatic document conveyance device.

(7) The present invention can be understood as a drive control method for controlling an electric motor that drives a driven body based on a speed difference between the fed back actual speed and a predetermined target speed. That is, during the acceleration control of the driven body, the speed difference during the acceleration control after a lapse of time from when the acceleration control is started until the speed difference becomes larger than a predetermined threshold is obtained. A first amplification stored in the storage means until a first step for determining whether or not the speed difference is equal to or smaller than a predetermined threshold and until the speed difference is determined to be equal to or smaller than a predetermined threshold by the first step. The second step of reading the rate and generating a first control value corresponding to the speed difference using the first amplification factor, and the speed difference is determined to be equal to or less than a predetermined threshold by the first step. After that, a third step of reading a second gain larger than the first gain from the storage means and generating a second control value according to the speed difference using the second gain, The present invention as a drive control method comprising It may be grasped.

  According to the present invention, the overshoot at the time of starting the driven body is reduced to improve the followability of the actual speed, and the speed of the driven body due to disturbance factors such as the eccentricity of the motor shaft and the cogging torque of the motor It is possible to reduce fluctuations.

  Further, according to the present invention, it is possible to reduce the time required for the stopped carriage to move, and to reduce the overshoot after the carriage starts moving.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing the external configuration of the multifunction machine 1. FIG. 2 is a partially enlarged cross-sectional view showing the main configuration of the printer unit 2. FIG. 3 is a plan view showing the main configuration of the printer unit 2, and mainly shows the configuration on the back side of the apparatus from the approximate center of the printer unit 2. FIG. 4 is a graph showing speed characteristics (speed transition) of the carriage 38. FIG. 5 is a block diagram illustrating a main configuration of the control unit 100 of the printer unit 2. FIG. 6 is a block diagram showing in detail the configuration of the ASIC 107 in FIG. FIG. 7 is a block diagram showing in detail the configuration of the PID calculation unit 124 in FIG. FIG. 8 is a flowchart illustrating an example of a procedure of calculation processing performed by the PID calculation unit 124 during acceleration control of the carriage 38. FIG. 9 is a graph showing speed characteristics (speed change) of the carriage 38 that is acceleration-controlled by the control unit 100.

[Multifunction machine 1]
The multi-function device 1 is a multi-function device (MFP: Multi Function Product) that integrally includes a printer unit 2 and a scanner unit 3, and has a print function, a scan function, a copy function, a facsimile function, and the like. As shown in FIG. 1, the multifunction machine 1 is formed in a substantially rectangular parallelepiped, the lower part is a printer part 2, and the upper part is a scanner part 3. The printer unit 2 corresponds to the image recording apparatus of the ink jet recording system of the present invention, and the scanner unit 3 corresponds to the image reading apparatus of the present invention.

  The printer unit 2 of the multifunction machine 1 records images and documents on recording paper (an example of a recording medium according to the present invention) based on predetermined print data. The printer unit 2 has an opening 9 formed in the front. The paper feed tray 20 and the paper discharge tray 21 are provided in two upper and lower stages inside the opening 9. The recording paper stored in the paper supply tray 20 is fed into the printer unit 2 and a desired image is recorded on the recording paper. Thereafter, the recording paper on which the image has been recorded is discharged to the paper discharge tray 21.

  The scanner unit 3 is configured as a so-called flat bed scanner. A document cover 30 as a top plate of the multifunction device 1 is provided on the upper portion of the scanner unit 3 so as to be freely opened and closed. A platen glass (not shown) and a plurality of CIS image sensors (an example of the image reading element of the present invention) are provided below the document cover 30. The plurality of CIS image sensors are mounted on a carriage (not shown) in a state of being arranged in a line in the depth direction (arrangement direction) of the multifunction device 1. The carriage is configured to be movable in a direction (moving direction) perpendicular to the arrangement direction along the back surface of the platen glass. In the process of moving the carriage in the moving direction, the image of the document placed on the platen glass is read by the CIS image sensor.

  As shown in FIG. 1, an operation panel 4 for operating the printer unit 2 and the scanner unit 3 is provided in the upper front portion of the multifunction machine 1. The operation panel 4 includes various operation buttons and a liquid crystal display unit. The multifunction device 1 operates based on an operation instruction from the operation panel 4. When the multifunction device 1 is connected to an external computer, the multifunction device 1 also operates based on an instruction transmitted from the computer via a printer driver or a scanner driver.

[Printer unit 2]
As shown in FIG. 2, a paper feed tray 20 is provided on the bottom side of the multifunction machine 1. A paper feed roller 25 is provided above the paper feed tray 20. A base shaft 29 is supported on a frame (not shown) of the printer unit 2. The base end of the paper feeding arm 26 is rotatably supported by the base shaft 29. The paper feed roller 25 is rotatably supported at the tip of the paper feed arm 26. An LF motor 95 (see FIG. 5) for rotating the paper feed roller 25 is connected to the base shaft 29. The paper feed arm 26 is provided with a gear drive mechanism 27 that transmits the rotational driving force of the LF motor 95 input from the base shaft 29 to the paper feed roller 25. The rotational driving force of the LF motor 95 is transmitted to the paper feed roller 25 via the base shaft 29 and the gear drive mechanism 27. As a result, the paper feed roller 25 is driven to rotate.

  When the sheet feeding roller 25 is rotated and pressed against the recording sheet on the sheet feeding tray 20, the uppermost recording sheet is fed by the frictional force between the roller surface of the sheet feeding roller 25 and the recording sheet. It is sent out to the back side (the right side in FIG. 2) of the paper tray 20. The leading edge of the recording paper abuts on the inclined plate 22 and is guided upward. A sheet conveyance path 23 extends from the inclined plate 22. Specifically, the sheet conveyance path 23 is directed upward from the inclined plate 22 and bent to the front side (left side in FIG. 2) of the multifunction machine 1, and then from the back side to the front side of the multifunction machine 1. And extends to the paper discharge tray 21 through the lower part of the image recording unit 24. Accordingly, the recording paper stored in the paper feed tray 20 is guided by the paper conveyance path 23 so as to make a U-turn from the lower side to the upper side, reaches the image recording unit 24, and after image recording is performed by the image recording unit 24. The paper is discharged to the paper discharge tray 21.

  As shown in FIG. 2, an image recording unit 24 is disposed in the paper transport path 23. The image recording unit 24 includes an ink jet recording type recording head 39 (an example of the recording head of the present invention) and a carriage 38 (an example of a driven body of the present invention) on which the recording head 39 is mounted. The carriage 38 is supported so as to be slidable in a direction perpendicular to the recording sheet conveyance direction (a direction perpendicular to the paper surface of FIG. 2).

  The recording head 39 is disposed on the bottom surface of the carriage 38, and the nozzles of the recording head 39 are exposed on the lower surface of the carriage 38. Ink of each color is supplied to the recording head 39 from an ink cartridge (not shown) arranged inside the multifunction device 1. A platen 42 is provided to face the lower surface of the carriage 38. When each color ink is selectively ejected as fine ink droplets from the nozzles of the recording head 39 while the carriage 38 is reciprocated, an image is recorded on the recording paper conveyed on the platen 42.

  As shown in FIG. 3, a pair of guide rails 43 and 44 are arranged on the upper side of the sheet conveyance path 23. These guide rails 43 and 44 are opposed to each other with a predetermined distance in the recording paper conveyance direction (from the upper side to the lower side in FIG. 3) and are orthogonal to the recording paper conveyance direction (left and right in FIG. 3). Direction). The guide rails 43 and 44 are provided in the casing of the printer unit 2 and constitute a part of a frame constituting the printer unit 2.

  The guide rail 43 is disposed on the upstream side in the recording sheet conveyance direction. The guide rail 43 has a flat plate shape in which the length in the width direction (the left-right direction in FIG. 3) of the sheet conveyance path 23 is longer than the reciprocation range of the carriage 38. Further, the guide rail 44 is disposed on the downstream side in the conveyance direction of the recording paper. The guide rail 44 has a flat plate shape in which the length in the width direction of the paper transport path 23 is substantially the same as that of the guide rail 43. The carriage 38 is disposed so as to straddle the guide rails 43 and 44. Specifically, the end of the carriage 38 on the upstream side in the transport direction is placed on the guide rail 43, and the end of the carriage 38 on the downstream side in the transport direction is placed on the guide rail 44. 44 is arranged to be slidable in the extending direction.

  The edge 45 on the upstream side in the transport direction of the guide rail 44 is bent at a substantially right angle upward. The carriage 38 carried on the guide rails 43 and 44 slidably holds the edge 45 by a holding member such as a roller pair. Thus, the carriage 38 is positioned with respect to the recording paper conveyance direction and can slide in a direction orthogonal to the recording paper conveyance direction. That is, the carriage 38 is slidably supported on the guide rails 43 and 44 and reciprocates in a direction orthogonal to the conveyance direction of the recording paper with reference to the edge 45 of the guide rail 44.

  As shown in FIG. 3, a belt drive mechanism 46 is disposed on the upper surface of the guide rail 44. The belt drive mechanism 46 includes a drive pulley 47, a driven pulley 48, and an endless annular belt 49.

  The driving pulley 47 and the driven pulley 48 are provided in the vicinity of both ends in the width direction of the sheet conveying path 23. An endless annular belt 49 is stretched between the driving pulley 47 and the driven pulley 48. A CR motor 96 (an example of the electric motor of the present invention, see FIG. 5) for moving the carriage 38 is connected to the shaft of the drive pulley 47. The CR motor 96 is a servo motor manufactured so as to be suitable for feedback control. When the CR motor 96 is rotationally driven, the rotational driving force is transmitted to the drive pulley 47. Then, the belt 49 moves circumferentially by the rotation of the drive pulley 47. In addition to the endless annular belt 49, a belt 49 that fixes both ends of the endless belt to the carriage 38 may be employed.

  The carriage 38 is connected to a belt 49 on the lower surface side. Accordingly, the carriage 38 slides on the guide rails 43 and 44 with the edge 45 as a reference based on the circumferential motion of the belt 49. A recording head 39 is mounted on such a carriage 38, and the recording head 39 is reciprocated in the width direction of the paper transport path 23.

  As shown in FIG. 3, an encoder strip 50 is disposed on the guide rail 44. The encoder strip 50 is in the form of a strip made of a transparent resin. The encoder strip 50 has a pattern in which the light shielding portions and the light transmitting portions are arranged at an equal pitch. A pair of support ribs 33 and 34 are provided at both ends of the guide rail 44 in the width direction (movement direction of the carriage 38). Both ends of the encoder strip 50 are engaged with the support ribs 33 and 34, and are erected along the edge 45. The encoder strip 50 is tensioned by a spring or the like.

  An optical sensor 35 that is a transmissive sensor is provided on the upper surface of the carriage 38 at a position corresponding to the encoder strip 50. The optical sensor 35 includes a first photosensor (not shown) for position detection and a second photosensor (not shown) for origin detection. The first photosensor includes two light emitting elements (for example, LEDs) arranged slightly shifted in the moving direction of the carriage 38 and two light receiving elements (for example, photons) arranged corresponding to these light emitting elements. Transistor). The second photosensor includes one light emitting element and one light receiving element. An encoder strip 50 is disposed between a light emitting element and a light receiving element included in each photosensor. As described above, the optical sensor 35 and the encoder strip 50 are arranged to constitute a linear encoder for detecting the position of the carriage 38.

  In the first embodiment, when the optical sensor 35 reads the pattern of the encoder strip 50, a detection signal indicating the position information of the carriage 38 is obtained. This detection signal is input (feedback) to the ASIC 107 of the control unit 100 (see FIG. 5 as an example of the drive control apparatus of the present invention), which will be described later, and the position information of the carriage 38 is recognized. Further, the control unit 100 obtains the actual speed, acceleration, and moving direction of the carriage 38 from the input position information. The CR motor 96 (see FIG. 5) is driven by PID control (feedback control) based on feedback data such as position information, actual speed, acceleration, and moving direction.

  As shown in FIG. 3, a maintenance mechanism 51 is disposed in a range where the recording paper does not pass, that is, outside the image recording area by the recording head 39 (see FIG. 2). Specifically, the maintenance mechanism 51 is disposed at the right end of the platen 42 in FIG. The maintenance mechanism 51 prevents the ink in the nozzles of the recording head 39 from drying, and removes air bubbles and foreign matters from the nozzles. In the first embodiment, the standby position (home position) of the carriage 38 is set immediately above the maintenance mechanism 51. Therefore, when the image recording is not performed, the carriage 38 stands by at the standby position until an image recording instruction is input.

  As shown in FIG. 2, a pair of conveyance rollers 89 including a conveyance roller 87 and a pinch roller 88 are provided on the upstream side of the image recording unit 24. On the downstream side of the image recording unit 24, a pair of discharge rollers 92 having a discharge roller 90 and a spur 91 provided above the discharge roller 90 is provided. A gear driving mechanism 85 (see FIG. 5) composed of a plurality of gears is connected to the shaft of the conveying roller 87. The rotational driving force of the LF motor 95 (see FIG. 5) is transmitted to the shaft of the transport roller 87 via the gear drive mechanism 85. As a result, the transport roller 87 is rotated at a predetermined rotational speed, and the recording paper is transported through the paper transport path 23. The transport roller 87 and the paper discharge roller 90 are connected by a transmission mechanism such as a gear, and a driving force is transmitted from the transport roller 87 to the paper discharge roller 90 via the transmission mechanism. As a result, the transport roller 87 and the paper discharge roller 90 are driven synchronously.

  An encoder disk 52 is provided on the rotation shaft of the transport roller 87. On the periphery of the encoder disk 52, a pattern in which light shielding portions and light transmitting portions are alternately arranged at an equal pitch is described. An optical sensor 15 (see FIG. 5) is disposed at a position corresponding to the periphery of the encoder disk 52. The periphery of the encoder disk 52 is disposed between the light emitting element and the light receiving element of the optical sensor 15. The encoder disk 52 and the optical sensor 15 constitute a rotary encoder for detecting the rotational position of the transport roller 87. In the first embodiment, the pattern of the encoder disk 52 that rotates together with the transport roller 87 is read by the optical sensor 15. When the optical sensor 15 reads the pattern of the encoder disk 52, a detection signal indicating the rotational position information of the transport roller 87 is obtained.

  In the first embodiment, when an image recording instruction is input to the multifunction device 1 and the leading end of the recording area of the recording paper reaches below the recording head 39, the CR motor 96 (see FIG. 5) is driven by the control unit 100. Be controlled. As a result, the carriage 38 starts to slide from the standby position set at the right end in FIG. 3, and reciprocates in a direction (left and right direction in FIG. 3) perpendicular to the recording sheet conveyance direction.

  FIG. 4 shows ideal speed characteristics (speed transition) when the carriage 38 reciprocates. This speed characteristic is a so-called profile indicating the shift of the target speed of the carriage 38, and shows the target speed that the carriage 38 should reach in a certain time. According to the speed characteristics of FIG. 4, the carriage 38 starts to move from the state where it is stationary at the standby position by rotating the CR motor 96 in the forward rotation direction, and in the section t1, the carriage 38 moves in the forward direction (left direction in FIG. 3). And is driven at a constant speed when a predetermined speed is reached in the section t2. When approaching the end opposite to the standby position, the vehicle is decelerated in the section t3. Subsequently, the CR motor 96 is rotated in the reverse rotation direction, whereby the carriage 38 is accelerated in the backward direction (right direction in FIG. 3) in the section t4, and is driven at a constant speed when the predetermined speed is reached in the section t5. The When approaching the standby position, the vehicle is decelerated in the section t6. Thereafter, the operations in the sections t1 to t6 are repeated as necessary.

  However, the actual speed characteristics of the carriage 38 include the cogging torque of the CR motor 96 (see FIG. 5), the eccentricity of the output shaft of the CR motor 96, the eccentricity of the shaft of the drive pulley 47, and the sliding resistance of the guide rails 43 and 44. It fluctuates under the influence of disturbance factors such as fluctuations. For example, when the torque fluctuation due to the cogging torque is periodically generated, the speed characteristic of the carriage 38 is also periodically changed. In the first embodiment, the CR motor 96 is driven and controlled by the control unit 100 (see FIG. 5), which will be described later, so that the influence of the disturbance element is minimized, and the speed variation of the carriage 38 hardly occurs. Can be. Details of the drive control by the control unit 100 will be described later.

[Control unit 100]
Next, the main configuration of the control unit 100 provided in the printer unit 2 will be described with reference to FIG.

  The control unit 100 controls the entire operation of the printer unit 2, and controls the drive of the CR motor 96 and the LF motor 95 in addition to the discharge control of the recording head 39. As shown in FIG. 5, the control unit 100 mainly includes a CPU 101 that performs various calculations, a ROM 102, a RAM 103, an ASIC (Application Specific Integrated Circuit) 107, an interface (I / F) 108, and a CR motor driver. 110, an LF motor driver 111, and a head drive circuit 113 are connected by a bus 105 or the like.

  The interface 108 is for receiving signals such as print data output from a host computer (not shown).

In addition to a program for the CPU 101 to control various operations of the printer unit 2, an integral gain and a differential gain necessary for PID control of the CR motor 96 are stored in the ROM 102. Here, the PID control is a proportional action (P action) in which a deviation (speed difference) between a target speed and an actual speed is multiplied by a proportional gain to change an input value, and a cumulative value of the deviation is multiplied by an integral gain. A control method that combines an integration operation (I operation) for changing an input value and a differentiation operation (D operation) for changing an input value by multiplying a change in the deviation (that is, a derivative of the deviation) by a differential gain. . The above-described proportional gain, integral gain, and differential gain are generally called PID constants. In the first embodiment, PID constants (proportional gain, integral gain, differential gain) used for PID control are stored in the ROM 102. Among the proportional gain, an example and second proportional gain (second gain of the present invention (an example of a first amplification factor of the present invention) first proportional gain to be used for acceleration control of the carriage 38 in the stopped state ) is an example of the first generation hand stage of the PID operation unit 124 (the invention described below, an example of the internal memory 142 (storage means of the present invention in FIG. 6), stored in the reference Fig. 7).

  The RAM 103 is used as a storage area for temporarily recording various data used when the CPU 101 executes the various programs described above, or a work area for performing predetermined arithmetic processing.

  The EEPROM 104 stores data, settings, flags, etc. that should be retained even after the power is turned off. In the first embodiment, a profile for determining a target speed to be reached when the carriage 38 reciprocates, specifically, a speed characteristic shown in FIG. 4 is stored.

  The ASIC 107 is configured as a gate array that counts and calculates pulse signals from the optical sensor 35. The detailed configuration of the ASIC 107 will be described later.

  The CPU 101 stores print data received from a host computer (not shown) via the interface 108 in a predetermined storage area of the RAM 103 and drives the LF motor 95 according to a control program stored in the ROM 102 in advance. An arithmetic control operation for outputting various necessary control signals, image data is processed, print data for performing actual image recording is developed based on the image data, and the recording head 39 is driven based on this Processing to output a control signal is performed. In addition, a control signal from the ASIC 107 sends a head drive signal to the head drive circuit 113 in synchronization with the movement of the CR motor 96, or rotates the LF motor 95 via the LF motor driver 111 in accordance with the movement of the CR motor 96. It also plays a role of supervising the operation of each part, such as making it happen.

  Based on the print data obtained from the input image data, the head drive circuit 113 detects the piezoelectric element (provided in the recording head 39) when the image recording location on the recording paper reaches below the recording head 39. A voltage is applied to (not shown), and ink is ejected toward the recording paper.

  The LF motor 95 is a DC motor. The rotary position of the LF motor 95 is detected by a rotary encoder constituted by the encoder disk 52 and the optical sensor 15 (see FIG. 5) attached to the rotation shaft of the transport roller 87, and the detection result is input to the ASIC 107. Based on the detection result, a PWM signal for accurately controlling the LF motor 95 is generated in the ASIC 107 so that the conveyance amount of the recording sheet by the conveyance roller 87 becomes a predetermined amount, and the PWM signal is transmitted to the LF motor driver 111. input. The LF motor driver 111 outputs a current corresponding to the input PWM signal to the LF motor 95. The output current flows to the LF motor 95, whereby the transport roller 87 is driven as desired.

  Due to the rotation of the LF motor 95, the driving force is transmitted to the transport roller 87 and the paper discharge roller 90 through a transmission mechanism such as a gear, so that the recording paper is transported. The transport position of the transported recording paper is detected by a sheet sensor (not shown) disposed in the paper transport path 23, and this detection signal is sent to the CPU 101. Upon receiving this signal, the CPU 101 determines the state of the recording paper, and drives or stops the LF motor 95 via the ASIC 107 and the LF motor driver 111.

  The ASIC 107 outputs a drive control signal to the CR motor driver 110 under the control of the CPU 101. The CR motor driver 110 outputs a drive current corresponding to the drive control signal to the CR motor 96. Upon receiving the drive current, the CR motor 96 moves the carriage 38, the position of the carriage 38 is detected by the optical sensor 35, and the position information is fed back to the ASIC 107.

[ASIC107]
Here, the configuration of the ASIC 107 will be described in detail with reference to FIG. In FIG. 6, the control system related to the LF motor 95 is omitted, and the control related to the LF motor 95 is also omitted in the following description.

The ASIC 107 includes an edge detection unit 121, a carriage position management unit 122, an encoder period measurement unit 123, a PID calculation unit 124, and a PWM generation unit 125. Each of these units is a hard logic circuit that is circuit-designed so that elements such as transistors and capacitors are integrated to realize a specific function described later. Incidentally, the PWM generator 125 and the CR motor driver 110, the first control means of the present invention, the second control hand stage is implemented.

  The edge detector 121 detects the edges (rising edges) of the encoder signals ENC1 and ENC2 generated by the optical sensor 35, and generates a reference pulse at the detection timing. The generated reference pulse is output to the carriage position management unit 122 and the encoder cycle measurement unit 123. Further, the edge detection unit 121 obtains the traveling direction of the carriage 38 from the phase difference between the two types of encoder signals ENC1 and ENC2, and outputs a direction flag signal having the direction as a flag to the carriage position management unit 122.

  The carriage position management unit 122 increments the pulse signal based on the direction flag signal and the reference pulse input from the edge detection unit 121 to obtain the position of the carriage 38 from the standby position (the right end in FIG. 3). Thereby, the traveling position of the carriage 38 is detected. The position of the carriage 38 detected here is fed back to the CPU 101.

  The encoder period measurement unit 123 obtains the speed of the carriage 38. Specifically, the encoder cycle measuring unit 123 obtains the speed of the carriage 38 by counting the reference pulses output from the edge detecting unit 121 within a certain time given by a reference timer (not shown). The obtained speed information is output to the PID calculation unit 124.

  The PID calculation unit 124 calculates PID control for speed control of the carriage 38 and generates a control signal to be output to the PWM generation unit 125. The integral gain and differential gain stored in the ROM 102 are given to the PID calculation unit 124 by the CPU 101. In this PID calculation unit 124, various calculations for PID control and generation of control signals are performed based on the speed information input from the encoder period measurement unit 123 and the integral gain and differential gain input from the CPU 101. .

  The PWM generation unit 125 generates a control signal from the PID calculation unit 124 and a PWM (Pulse Width Modulation) signal corresponding to the CPU 101. The PWM generation unit 125 obtains a predetermined duty ratio (a ratio of the ON time and the OFF time, which is expressed as a ratio of the ON time to a certain period) based on the control signal from the PID calculation unit 124. . Then, a PWM signal having this duty ratio is generated. The generated PWM signal is output to the CR motor driver 110. Upon receipt of the PWM signal, the CR motor driver 110 applies a drive current corresponding to the PWM signal to the CR motor 96 to rotate the CR motor 96. The rotational driving force of the CR motor 96 is transmitted to the carriage 38 via the belt driving mechanism 46. As a result, the carriage 38 moves in a predetermined direction at a predetermined speed.

  Here, the configuration of the PID calculation unit 124 will be described in detail with reference to FIG.

PID operation unit 124 includes a PID output unit 141, an internal memory 142, a gain selection unit 144 is constituted by the speed comparing unit 145 (an example of a first determination hand stage of the present invention). Note that each of the PID output unit 141, the gain selection unit 144, and the speed comparison unit 145 is a hard logic circuit that is circuit-designed to integrate elements such as transistors and capacitors so as to realize a specific function described later that each unit has. It is.

  The internal memory 142 stores a part of a proportional gain used for proportional operation (P operation) in PID control, and is constituted by a semiconductor memory such as a RAM. The internal memory 142 stores two gains, a first proportional gain and a second proportional gain used for acceleration control of the carriage 38. The second proportional gain has a larger value than the first proportional gain. In short, in the acceleration control of the carriage 38, two gains having different numerical values are used. In the first embodiment, in the acceleration region (section t1 in FIG. 4), proportional operation is performed with the first proportional gain at the initial stage where acceleration is started, and proportional operation is performed with the second proportional gain after a predetermined switching timing. Is done. The numerical values of the first proportional gain and the second proportional gain are elements that are determined in consideration of characteristics unique to each member such as the CR motor 96 and the belt driving mechanism 46 that are involved in driving the carriage 38.

  In the first embodiment, the first proportional gain and the second proportional gain are stored in the internal memory 142 of the PID calculation unit 124. However, the first proportional gain and the second proportional gain are stored in the ROM 102. The first proportional gain or the second proportional gain may be read from the ROM 102 as necessary.

  The speed comparison unit 145 compares the deviation (speed difference) between the target speed and the actual speed of the carriage 38 with a predetermined reference value, and the deviation is the reference value (corresponding to the predetermined threshold value of the present invention). Determine if: Specifically, a deviation between the target speed input from the CPU 101 and the actual speed input from the encoder period measurement unit 123 is obtained, and it is determined whether the obtained deviation is equal to or less than the reference value. In the first embodiment, the reference value is set to a value that is small enough to be evaluated as substantially zero with respect to the target speed, for example. Specifically, the reference value is set to a value of approximately 10%, more preferably 5%, with respect to the speed required in the constant speed control section of the carriage 38. As a result, the speed comparison unit 145 can determine whether or not the deviation is substantially zero. The determined result is output to the gain selection unit 144 as a signal sig1 in which the determination result is replaced with a current value. Here, the signal sig1 is a signal indicating a determination result that the deviation is equal to or less than the reference value.

  Further, the reference value may be set to a value determined by a method other than the above. For example, the reference value may be a ratio provided with respect to a value (deviation ratio) obtained by dividing a deviation (speed difference) between the target speed and the actual speed of the carriage 38 by the target speed. That is, the reference value may be determined as a predetermined ratio (ratio) with respect to the target speed instead of a specific numerical value for the deviation. In this case, the speed comparison unit 145 compares the reference value with the ratio of the deviation to the target speed, and determines whether the deviation is equal to or less than the reference value.

  The gain selection unit 144 selects a first proportional gain or a second proportional gain from the internal memory 142 in accordance with the presence or absence of the signal sig1 input from the speed comparison unit 145 in the acceleration control of the carriage 38. Have When the signal sig1 is input to the gain selection unit 144 during acceleration control of the carriage 38, the second proportional gain is read from the internal memory 142, and the second proportional gain is output to the PID output unit 141. On the other hand, when the signal sig1 is not input to the gain selection unit 144, the first proportional gain is read from the internal memory 142, and the first proportional gain is output to the PID output unit 141. Note that when performing control other than acceleration control of the carriage 38, the CPU 101 reads a necessary proportional gain from the ROM 102 and outputs it to the PID output unit 141. In addition, gains other than the proportional gain (integral gain, differential gain) are read from the ROM 102 and output to the PID output unit 141 regardless of the control state of the carriage 38.

  The PID output unit 141 obtains a deviation between the actual moving speed (actual speed) of the carriage 38 input from the encoder period measuring unit 123 and the target speed input from the CPU 101. Then, PID control is calculated using PID constants (proportional gain, integral gain, differential gain) input from the CPU 101 or the gain selection unit 144, and a control signal corresponding to the obtained deviation is generated, The control signal is output to the PWM generator 125.

  Hereinafter, an example of the acceleration control method for the carriage 38 will be described with reference to the flowchart of FIG. 8 and the graph of FIG. 9 together with the procedure of the calculation process performed by the PID calculation unit 124 during the acceleration control of the carriage 38. The calculation processing is executed after preparation for movement control of the carriage 38 is completed, as will be described later. This calculation process starts from step S1 in FIG. In FIG. 9, the broken line is the target speed profile, and the solid line is the speed characteristic of the carriage 38. A section t10 indicates an acceleration control area, and a section t20 indicates a constant speed control area.

  When a print instruction together with print data from an external host computer or the like is input to the multi function device 1 via the interface 108, maintenance of the recording head 39 by the maintenance mechanism 51 (see FIG. 3), cueing conveyance of the recording paper, standby position The carriage 38 is moved from the recording start position to the recording start position, and preparation for movement control of the carriage 38 is completed. Note that the recording start position is not the end position of the image recording area where recording is actually performed on the recording paper, but rather the end run required for the carriage 38 to reach a predetermined speed from the stopped state. It means a position that has been retracted by a distance. When the carriage 38 is disposed at the recording start position, drive control of the CR motor 96 is started by the ASIC 107 and the CR motor driver 110 of the control unit 100. Thereby, the movement control of the carriage 38 in the stopped state is started. Hereinafter, a calculation process performed by the PID calculation unit 124 during the acceleration control of the carriage 38 will be described in detail.

  At the recording start position, the carriage 38 is in a stopped state. In the initial stage of acceleration control in which movement with respect to the stopped carriage 38 is started, the gain selection unit 144 reads the first proportional gain from the internal memory 142 and outputs the first proportional gain to the PID output unit 141 (S1).

The PID output unit 141 uses the first proportional gain input from the gain selection unit 144, the integral gain and the differential gain input from the CPU 101, and a first control signal (the main control signal corresponding to the deviation between the target speed and the actual speed). An example of the first control value of the invention is generated and output to the PWM generator 125 (S2). The PWM generator 125 generates a PWM control signal having a duty ratio corresponding to the input first control signal and outputs the PWM control signal to the CR motor driver 110. The CR motor driver 110 drives the drive current according to the PWM control signal. Is output to the CR motor 96. At this time, if the driving force transmitted from the CR motor 96 to the carriage 38 becomes larger than the static friction force acting on the carriage 38, the carriage 38 starts to move and is accelerated.

  During acceleration control of the carriage 38, the speed comparison unit 145 determines whether or not the deviation between the target speed input from the CPU 101 and the actual speed input from the encoder period measurement unit 123 is equal to or less than the reference value. (S3). As shown in FIG. 9, the deviation is substantially zero immediately after the acceleration control is started, but in the first embodiment, a time Δt from when the acceleration control starts until the deviation exceeds the reference value has elapsed. Until this is done, the determination process in step S3 is not performed.

If it is determined in step S3 that the deviation is equal to or less than the reference value (S3: Yes), the speed comparison unit 145 outputs the signal sig1 to the gain selection unit 144 (S4). Receiving this signal sig1, the gain selection unit 144 reads out the second proportional gain larger than the first proportional gain from the internal memory 142, and outputs it to the PID output unit 141 (S5). The PID output unit 141 generates a second control signal (an example of the second control value of the present invention) according to the deviation using the second proportional gain, the integral gain and the differential gain input from the CPU 101, and outputs the PWM. It outputs to the production | generation part 125 (S6). The PWM generator 125 generates a PWM control signal having a duty ratio corresponding to the input second control signal and outputs the PWM control signal to the CR motor driver 110. The CR motor driver 110 drives the drive current according to the PWM control signal. Is output to the CR motor 96.

  If it is determined in step S3 that the deviation is not less than or equal to the reference value (S3: No), the signal sig1 is not output to the gain selection unit 144. Therefore, each process is repeated in the above-described steps S2 and S3 until it is determined that the deviation is equal to or less than the reference value.

Thus, as shown in FIG. 9, (an example between the first district of the present invention) interval t11 until the deviation is determined to be equal to or less than the reference value, relatively numerical small first proportional Since the CR motor 96 is PID controlled using the gain, even if the deviation becomes large because the carriage 38 does not move due to the influence of the static frictional force acting on the carriage 38, the first control signal does not become excessive. . Therefore, the actual speed does not greatly exceed the target speed. Therefore, in the section t11, the actual speed of the carriage 38 does not vibrate with respect to the target speed, and the control of the CR motor 96 is stabilized.

Further, (an example between second district invention) interval t12 from after the deviation is determined to be less than the reference value until the constant speed control is started, the second greater than the first proportional gain Since the CR motor 96 is PID controlled using the proportional gain, the carriage 38 is stably driven without being affected by disturbance factors such as eccentricity of the output shaft of the CR motor 96 and cogging torque. Further, since the control by the second control signal is started when the deviation becomes equal to or less than the reference value, a slight speed fluctuation occurs at the transition from the section t11 to the section t12, but the actual speed of the carriage 38 is large. Does not fluctuate in vibration.

  When the CPU 101 determines that the carriage 38 has reached the end position (predetermined position) of the image recording area where recording is actually performed on the recording paper based on the signal from the optical sensor 35, the determination result is sent from the CPU 101. Input to the PID output unit 141. The PID output unit 141 determines whether the carriage 38 has reached the end position based on the presence / absence of the determination result (S7). When the PID output unit 141 receives the determination result (S7: Yes), the PID constant (proportional gain, proportional to the constant speed control) input from the CPU 101 is used without using the proportional gain input from the gain selection unit 144. A control signal corresponding to the deviation is generated using an integral gain and a differential gain, and is output to the PWM generator 125. As a result, the acceleration control of the carriage 38 is completed and switched to the constant speed control. As in the case of the constant speed control, the carriage 38 deceleration control generates a control signal corresponding to the deviation using a PID constant corresponding to the deceleration control input from the CPU 101, and sends it to the PWM generator 125. This is done by outputting.

  If it is determined in step S7 that the carriage 38 has not reached the end position of the image recording area (S7: No), the processes in the steps S5 and S6 described above are repeated.

  In the first embodiment described above, the PID output unit 141, the gain selection unit 144, and the speed comparison unit 145 constituting the PID calculation unit 124 are hard logic circuits. For example, the unique functions of each unit can be realized. The processing of each procedure in the flowchart shown in FIG. 8 may be performed by the CPU 101 performing arithmetic processing according to a program.

  In the first embodiment described above, the target speed profile (see FIG. 4) stored in advance in the EEPROM 104 is used. However, the target speed profile created each time the carriage 38 is controlled to move is used. Also good. For example, after the maintenance of the recording head 39 is completed, the carriage 38 is reciprocated once according to a test program stored in the ROM 102 in advance, and the position, speed, acceleration, etc. of the carriage 38 obtained by the optical sensor 35 at that time It is conceivable to create a target speed profile based on the above data. Note that the profile created in this way may be temporarily stored in the RAM 103 or the EEPROM 104.

Second Embodiment
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 10 and 11. When the second embodiment is different from the first embodiment described above, (an example of a second generation hands-stage of the present invention) control signal compensation unit 148 to the PID operator 154 according to the second embodiment is provided The other configurations are the same as those in the first embodiment. Therefore, in the following, constituent elements common to the constituent elements in the first embodiment described above are denoted by the same reference numerals as those used in the first embodiment, and detailed description thereof is omitted. FIG. 10 is a block diagram showing in detail the configuration of the PID calculation unit 154 according to the second embodiment. FIG. 11 is a graph showing the speed characteristics (speed change) of the carriage 38 that is acceleration-controlled by the control unit 100 having the PID calculation unit 154.

  In the following, the control signal compensation unit 148 of the PID calculation unit 154 and the operational effects obtained by providing it will be described.

As described above, since the static friction force acts on the carriage 38 in the stopped state, the carriage 38 does not move until the driving force transmitted to the carriage 38 becomes larger than the static friction force. In particular, when the CR motor 96 is controlled using the first proportional gain having a relatively small numerical value in the section t11 as in the first embodiment, it takes time until the carriage 38 starts to move as shown in FIG. In the second embodiment (an example between the third district of the invention, see FIG. 11) actually period T 13 until the carriage 38 starts to move from the start the acceleration control of the carriage 38 in, the PID output unit 141 By adding a predetermined auxiliary control signal AUX (an example of the auxiliary control value of the present invention) to the input first control signal, the first control signal to the third control signal (the third control value of the present invention). and generating one example) of a.

  In the second embodiment, when the auxiliary control signal AUX is input to the PWM generation unit 125 as a signal having a magnitude corresponding to the static frictional force of the carriage 38 in the stopped state, specifically, only the auxiliary control signal AUX is input to the PWM generator 125. Assuming that the static frictional force acting on the carriage 38 is equal to the driving force transmitted to the carriage 38, the signal is of a magnitude. Further, when the static friction force varies depending on the stationary position of the carriage 38 and the environment, the magnitude of the auxiliary control signal AUX is set to a signal that is considered to be equal to the smallest static friction force. That is, if the magnitude of the static friction force and the driving force transmitted to the carriage 38 by the auxiliary control signal AUX are equal, the driving force transmitted to the carriage 38 based on the auxiliary control signal AUX and the static friction force acting on the carriage 38 And the influence of the static friction force can be reduced even when the driving force transmitted to the carriage 38 by the auxiliary control signal AUX is small relative to the magnitude of the static friction force. In other words, by adding the auxiliary control signal AUX to the first control signal, the carriage 38 can be driven while reducing the influence of static friction. That is, the carriage 38 in the stopped state does not start unless the driving force transmitted to the carriage 38 is larger than the static friction force acting on the carriage 38, but the static friction force acting on the carriage 38 by the auxiliary control signal AUX. Since the auxiliary control signal AUX is not added to the first control signal, the time required for the carriage 38 to start moving can be shortened. Further, since the movement of the carriage 38 can be accelerated, the deviation between the target speed and the actual speed does not increase, and the first control signal does not become excessive. For this reason, the actual speed does not greatly overshoot the target speed. That is, since the influence of the static frictional force acting on the carriage 38 can be reduced, the movement of the carriage 38 starts faster and the deviation does not increase. Therefore, the actual speed of the carriage 38 is oscillated with respect to the target speed. The fluctuation is prevented and the control of the CR motor 96 is stabilized. That is, the followability of the actual speed with respect to the target speed is improved.

The CPU 101 determines whether or not the carriage 38 has started to move. Specifically, it is determined whether the carriage 38 has started to move based on the position information of the carriage 38 fed back from the carriage position management unit 122 to the CPU 101. Note that the CPU 101 may directly determine the movement of the carriage 38 by directly monitoring the reference pulse using the reference pulse generated from the edge detection unit 121 when the position of the carriage 38 changes. Thus, CPU 101 determines start moving the carriage 38 corresponds to the second determination hand stage of the present invention.

When the CPU 101 determines that the carriage 38 has started to move, the determination result is output to the control signal compensation unit 148 as the signal sig2 replaced with the current value. That is, the signal sig2 is a signal indicating that the carriage 38 has started to move. In the acceleration control of the carriage 38, the control signal compensator 148 generates the third control signal by adding the auxiliary control signal AUX to the first control signal from the PID output unit 141 until the signal sig2 is input. Then, the generated third control signal is output to the PWM generator 125. The PWM generator 125 generates a PWM control signal having a duty ratio corresponding to the input third control signal, and causes the CR motor driver 110 to output a drive current to the CR motor 96. On the other hand, the signal sig2. When input to the control signal compensation unit 148, the auxiliary control signal AUX is not added to the first control signal. That is, during acceleration control, the only period T 13, a than the first control signal is converted to a third control signal, in a section excluding a section T 13 is the same acceleration control as the first embodiment described above Is done.

Thus, in the second embodiment, the interval T 13 until the carriage 38 actually starts moving, the third control obtained by amplifying the first control signal generated by the comparatively small numerical first proportional gain Since the CR motor 96 is PID controlled by the signal, the carriage 38 starts to move at an early timing. That is, the time until the carriage 38 starts to move can be shortened.

  In the first embodiment and the second embodiment described above, the carriage 38 of the printer unit 2 is described as an example of the driven body of the present invention. For example, the scanner unit 3 holds the CIS image sensor while holding the CIS image sensor. The present invention can also be applied to acceleration control of a carriage that moves in the scanning direction. Further, the image is not limited to the image recording apparatus of the ink jet recording system, and an image of the original is imaged by a conveyance roller for conveying a recording sheet in a so-called thermal printer, or an automatic document feeder called ADF. The present invention can also be applied to the case where acceleration control is performed on a conveying roller for conveying toward a reading position. Of course, the present invention is not limited to these driven bodies, and the present invention can be applied to a case where various driven bodies that are driven by a motor are subjected to acceleration control.

FIG. 1 is a perspective view showing an external configuration of the multifunction machine 1. FIG. 2 is a partially enlarged cross-sectional view showing the main configuration of the printer unit 2. FIG. 3 is a plan view showing the main configuration of the printer unit 2, and mainly shows the configuration on the back side of the apparatus from the approximate center of the printer unit 2. FIG. 4 is a graph showing speed characteristics (speed transition) of the carriage 38. FIG. 5 is a block diagram illustrating a main configuration of the control unit 100 of the printer unit 2. FIG. 6 is a block diagram showing in detail the configuration of the ASIC 107 in FIG. FIG. 7 is a block diagram showing in detail the configuration of the PID calculation unit 124 in FIG. FIG. 8 is a flowchart illustrating an example of a procedure of calculation processing performed by the PID calculation unit 124 during acceleration control of the carriage 38. FIG. 9 is a graph showing speed characteristics (speed change) of the carriage 38 that is acceleration-controlled by the control unit 100. FIG. 10 is a block diagram showing in detail the configuration of the PID calculation unit 154 according to the second embodiment. FIG. 11 is a graph showing the speed characteristics (speed change) of the carriage 38 that is acceleration-controlled by the control unit 100 having the PID calculation unit 154. FIG. 12 is a graph showing the speed characteristic (speed change) of the carriage when affected by the cogging torque. FIG. 13 is a block diagram showing a configuration of a conventional feedback control system 200. FIG. 14 is a graph showing the carriage speed characteristic (speed change) when the conventional feedback control system 200 is applied.

DESCRIPTION OF SYMBOLS 1 ... MFP 2 ... Printer part 35 ... Optical sensor 38 ... Carriage 39 ... Recording head 46 ... Belt drive mechanism 50 ... Encoder strip 95 ... LF motor 96- ..CR motor 100 ... control unit 101 ... CPU
102 ... ROM
103 ... RAM
104 ... EEPROM
107 ... ASIC
110 ... CR motor driver 111 ... LF motor driver 113 ... head drive circuit 121 ... edge detection unit 122 ... carriage position management unit 123 ... encoder period measurement unit 124 ... PID calculation Unit 125 ... PWM generation unit 141 ... PID output unit 142 ... internal memory 145 ... speed comparison unit 144 ... gain selection unit 148 ... control signal compensation unit

Claims (7)

A drive control device that controls an electric motor that drives a driven body based on a speed difference between a fed back actual speed and a predetermined target speed,
Storage means storing a first amplification factor for amplifying a control value used for controlling the electric motor and a second amplification factor larger than the first amplification factor;
During the acceleration control of the driven body, the speed difference during the acceleration control after a lapse of time from the start of the acceleration control until the speed difference becomes larger than a predetermined threshold is a predetermined value . First determination means for determining whether or not a threshold value or less;
In the first interval until the speed difference is determined to be equal to or less than a predetermined threshold by the first determination means, a first control value corresponding to the speed difference is generated using the first gain. First generation for generating a second control value corresponding to the speed difference using the second amplification factor in the second section after the speed difference is determined by the first determination means to be equal to or less than a predetermined threshold. Means,
A drive control apparatus comprising: Second determination means for determining whether or not the driven body has started to move from a stopped state;
Second generation means for generating a third control value by adding a predetermined auxiliary control value to the first control value in a third interval until the second determination means determines that the driven body has started to move; The drive control device according to claim 1, further comprising:   2. The drive control device according to claim 1, further comprising first control means for controlling the electric motor by outputting a driving current corresponding to either the first control value or the second control value to the electric motor.   3. The apparatus according to claim 2, further comprising a second control unit that outputs a drive current corresponding to any one of the first control value, the second control value, and the third control value to the electric motor to control the electric motor. Drive control device. The driven body includes a carriage mounted with a recording head in an ink jet recording type image recording apparatus and capable of reciprocating in a direction crossing the conveyance direction of the recording medium, or a plurality of image reading elements in the image reading apparatus. to drive control apparatus according to any one of claims 1 to 4 which is the image reading reciprocally movable carriage in a direction intersecting the array direction of the element. The driven body, conveying rollers for conveying the recording medium in the image recording apparatus of thermal, or to any one of claims 1 to 4 which is the conveying roller for conveying the original in the automatic document feeder The drive control apparatus described. A drive control method for controlling an electric motor that drives a driven body based on a speed difference between a fed back actual speed and a predetermined target speed,
During the acceleration control of the driven body, the speed difference during the acceleration control after a lapse of time from the start of the acceleration control until the speed difference becomes larger than a predetermined threshold is a predetermined value . A first step of determining whether or not a threshold value or less;
Until the speed difference is determined to be less than or equal to a predetermined threshold value by the first step, the first amplification factor stored in the storage means is read out and the speed difference is calculated using the first amplification factor. A second step of generating a corresponding first control value;
After it is determined in the first step that the speed difference is equal to or less than a predetermined threshold value, a second gain larger than the first gain is read from the storage means, and the second gain is used. A third step of generating a second control value according to the speed difference;
A drive control method comprising:

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