JP2009055673A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller capable of stopping a motor at a proper timing without forcibly executing complicated computation. <P>SOLUTION: The motor controller is provided with: a driven object; a motor; a measuring means for measuring the temperature of the driven object; a memory for associating each of threshold values to each of combinations of speed data and load data; a designating means for designating speed; a specifying means for specifying the load of the driven object; a judging means for specifying a threshold value stored in the memory in association with the combination of the speed and load, and judging whether or not the measured temperature exceeds the threshold value; and a control means, as a means for intermittently driving the driven object through supply of power to the motor, which adjusts the supply amount of power to the motor until the driven object is driven at a designated speed every time the motor is driven intermittently and delays the timing of start of driving of the driven object by a predetermined time after it is judged that the temperature exceeds the threshold value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor control device.

  The ink jet printer has a CR (Carriage) motor that reciprocates the carriage in the scanning direction, and a PF (Paper Feed) motor that conveys the paper stored in the paper feed tray to the paper discharge tray via the carriage. It is equipped with various DC motors. Since the CR motor and the PF motor are frequently started and stopped for driving the carriage and feeding the paper, heat generated in accordance with the power consumption is accumulated in these motors. If the heat builds up and overheats, it can cause problems such as winding coil burning, smoke, and fire, so this type of printer pauses its operation whenever the motor heat exceeds a certain threshold. It is equipped with a mechanism for pause control.

Patent Document 1 discloses a mechanism for accurately performing pause control. The ink jet printer disclosed in this document calculates the unit heat generation amount of the motor from the effective current value of the motor during one reciprocation of the carriage and the driving time required for the movement, and considers natural heat dissipation. A heat generation temperature ΔT is calculated based on a value obtained by integrating the heat generation amount. Then, it is determined which of the three preset threshold values the exothermic temperature ΔT exceeds, and a pause time having a length corresponding to the magnitude of the threshold value that has been exceeded is given.
JP 2003-79179 A

  By the way, the control unit of the printer disclosed in Patent Document 1 applies the PWM (Pulse Width Modulation) duty value that determines the rotation amount of the DC motor and the rotation speed of the motor to the first function, thereby making effective use of the motor. The heat generation temperature ΔT is obtained by obtaining the current value and applying the effective current value to the second function. For this reason, there is a problem that many memory resources are required for these operations. Moreover, since the constants of the functions used for the calculation of the rotation speed and the heat generation temperature ΔT are set based on various measurement results when the motor is rotated under the assumed worst condition, The calculated heat generation temperature ΔT is generally higher than the actual temperature. As a result, there is a problem in that motor pause control is frequently performed at a timing that is not normally necessary, and the throughput of the printer itself is reduced.

  The present invention has been devised under such a background, and an object of the present invention is to provide a mechanism capable of stopping a motor at an appropriate timing without forcing a complicated calculation.

  A motor control apparatus according to a preferred aspect of the present invention measures a driven body, a motor that provides driving force to the driven body by rotation according to the amount of power supplied to the driven body, and the temperature of the driven body. And a memory for storing each threshold value used for comparison with the temperature of the driven body in association with each combination of speed data indicating speed and load data indicating load, and specifying means for specifying the speed A threshold value stored in the memory in association with a combination of speed data indicating the specified speed and a combination of load data indicating the specified load; A determination means for determining whether the threshold value is exceeded, and a means for intermittently driving the driven body through power supply to the motor, each time the intermittent driving is performed, the speed at which the driven body is designated To drive with Until adjusting the amount of power supplied to the motor, provided with a timing of the start of the driving of the driven body after the determination means temperature exceeds a threshold value is determined, and control means for delaying for a predetermined time. According to the present invention, the motor can be stopped at an appropriate timing without forcing a complicated calculation.

  The motor control device according to another preferred aspect of the present invention is a first controller that applies a driving force to the first driven body by rotation according to the first driven body and the amount of power supplied to the first driven body. Motor, a second driven body, a second motor that applies a driving force to the second driven body by rotation according to the amount of power supplied to itself, and a second driven body The measurement means for measuring the temperature and each threshold value used for comparison with the temperature of the second driven body are represented by speed data indicating the driving speed of the first driven body and the second driven body, A memory stored in association with each combination of load data indicating a load of one or both of the one driven body and the second driven body, a designation means for designating a speed, a first motor and a second Specific means of identifying the load on one or both of the motors and the specified speed Determining means for determining a threshold value stored in the memory in association with a combination of degree data and load data indicating the specified load, and determining whether the measured temperature exceeds the threshold value; the first motor and the second Means for intermittently driving each of the first driven body and the second driven body through the supply of electric power to the motor, and drives the first driven body or the second driven body. Each time the driven body is driven at a specified speed, the amount of power supplied to the motor that applies driving force to the driven body is adjusted, and the judging means determines that the temperature has exceeded the threshold value. And control means for delaying the start timing of driving the first driven body or the second driven body after the determination by a predetermined time. According to the present invention, the motor can be stopped at an appropriate timing without forcing a complicated calculation.

  The first driven body includes a roller that transports a medium that is an ejection target of ink droplets, and the second driven body transports a carriage that supports a recording head that ejects ink droplets and the carriage. And a measuring unit that measures the temperature of the recording head. According to the present invention, it is possible to pause the motor of a printer, which is a device equipped with a recording head and a movement support mechanism, at an appropriate timing.

  And a detecting means for detecting the speed of conveyance of the medium by the roller, and the specifying means is based on the amount of power supplied to the first motor when the detecting means detects the designated speed. The load may be specified. According to the present invention, it is possible to accurately specify the load of the motor mounted on the printer and to specify the optimum threshold value used for comparison with the temperature based on the load.

  And detecting means for detecting the speed of movement of the carriage, wherein the specifying means is based on the amount of power supplied to the second motor when the detecting means detects the designated speed. May be specified. Also according to the present invention, it is possible to accurately specify the load of the motor mounted on the printer and to specify the optimum threshold value used for comparison with the temperature based on the load.

  The designation means is designated as a selection acceptance means for accepting selection of one of a plurality of modes respectively associated with each combination of the speed of the first driven body and the speed of the second driven body. Speed specifying means for specifying a combination of speeds associated with each mode. According to the present invention, it is possible to specify an optimum threshold value used for comparison with temperature based on a combination of mode and load.

(Embodiment of the Invention)
Embodiments of the present invention will be described below with reference to the drawings. The ink jet printer according to the present embodiment can operate in three modes: a default mode, a dedicated paper photo mode, and a plain paper draft mode. Dedicated paper photo mode is a mode that forms dots of ink droplets with higher density than the default mode at a slower speed, and is specified when forming high-density color images such as photographs on dedicated paper such as glossy paper. The The plain paper draft mode is a mode in which dots of ink droplets having a lower density than the default mode are formed at a higher speed, and is specified when a low-density monochrome image such as a document is formed on plain paper.

  FIG. 1 is a diagram illustrating a schematic hardware configuration of an ink jet printer according to the present embodiment. As shown in FIG. 1, the printer includes a driving pulley 11 (corresponding to “second driven body”), a driven pulley 12 (corresponding to “second driven body”), a belt 13 (“second driving body”). "Corresponding to" driven body "), CR motor 14 (corresponding to" second motor "), linear scale 15, guide shaft 16, carriage 17 (corresponding to" second driven body "), ink cartridge 18, recording Head 19, linear encoder 20, drive roller 21 (corresponding to "first driven body"), PF motor 22 (corresponding to "first motor"), rotary scale 23, rotary encoder 24, control unit 30 (" The identification means ”, the“ determination means ”, the“ control means ”, and the“ detection means ”. These units are mounted on a chassis (not shown) serving as a housing.

  A left side wall 25 and a right side wall 26 are erected on the base (not shown) of the chassis so as to sandwich the left and right sides of the conveyance path for conveying paper (corresponding to “medium”) in the front-rear direction. A rear side wall 27 is erected so as to connect the rear ends of 25 and 26. In addition, a driving pulley 11 and a driven pulley 12 are mounted in two holes formed at a position slightly below the upper end of the rear side wall 27 at a distance substantially the same as the width of the sheet conveyance path. An endless belt 13 is wound around the pulleys 11 and 12. Further, the CR motor 14 is joined to the rear surface of the rear side wall 27, and the rotation shaft of the CR motor 14 is connected to the rotation shaft of the drive pulley 11. The CR motor 14 applies a driving force to the driving pulley 11 through its rotation.

  A linear scale 15 is provided on the front surface of the rear side wall 27 below the pulleys 11 and 12. The linear scale 15 has a structure in which light transmitting portions that transmit light and non-transmitting portions that do not transmit light are alternately arranged at a pitch of 1/180 inch between one end and the other end of an elongated plate. A guide shaft 16 is stretched slightly forward of the rear side wall 27 so as to connect the left side wall 25 and the right side wall 26. The guide shaft 16 is positioned at a height corresponding to the space between the belt 13 wound between the pulleys 11 and 12 and the linear scale 15. The direction of the arrangement of the transmission part and the non-transmission part of the linear scale 15 is parallel to the direction of the guide shaft 16. Further, a plurality of sheets can be accommodated in a sheet feeding member (hopper) located behind the rear side wall 27.

  The carriage 17 houses, for example, four color ink cartridges 18 of yellow (Y), magenta (M), cyan (C), and black (B), and these ink cartridges 18 and flow paths (not shown). The recording head 19 connected via the is provided on its lower surface. The recording head 19 includes a nozzle plate in which a series of nozzle openings for each color are arranged, a piezoelectric element that expands and contracts in response to charge and discharge, and a cavity that is sandwiched between the nozzle plate and the piezoelectric element. When the piezoelectric element is expanded and contracted while the ink supplied from the ink cartridge 18 is stored in the cavity, the ink is ejected from the nozzle opening as an ink droplet.

  A fixing tool (not shown) provided slightly below the upper end of the rear surface of the carriage 17 is fixed to a part of the belt 13, and a supporting tool (not shown) provided below the belt 13 is attached to the guide shaft 16. They are slidably connected to each other. Further, a linear encoder 20 is provided on the rear surface of the carriage 17. The linear encoder 20 is an optical sensor having a light projecting element and a light receiving element that face each other so as to sandwich the front and rear surfaces of the linear scale 15. The linear encoder 20 supplies two analog rectangular wave signals (A-phase signal and B-phase signal) that change according to the presence or absence of light reception by the light receiving element to the control unit 30. When the driving force is applied from the CR motor 14 and the driving pulley 11 rotates forward and backward, the carriage 17 moves from a position directly above the left end of the lateral width of the conveyance path (hereinafter referred to as a “moving left limit position”). The travel to the position right above the right end (hereinafter referred to as “moving right limit position”) is guided by the guide shaft 16 to reciprocate.

  Each time the carriage 17 moves and the light emitted from the light projecting element to the light receiving element of the linear encoder 20 is blocked by the transmission part of the linear scale 15, the level of the rectangular wave signal output from the linear encoder 20 changes from the low level. Switch to high level. Therefore, the position on the stroke of the carriage 17 can be determined based on the number of pulses of the rectangular wave signal output from the linear encoder 20, and the speed of the carriage 17 can be determined based on the period of the rectangular wave signal. .

  A drive roller 21 is provided below the carriage 17. A portion on the right end side of the rotation shaft of the drive roller 21 is connected to the rotation shaft of the PF motor 22 through a plurality of gears and to the center of the rotary scale 23. The PF motor 22 applies a driving force to the driving roller 21 through its own rotation.

  The rotary scale 23 connected to the rotating shaft of the PF drive roller 21 includes a plurality of rectangular light-transmitting portions extending radially outward from the center of the disk-shaped plate between adjacent light-transmitting portions. It has a structure that is arranged in a ring with a predetermined interval. A non-light-transmitting part is formed between the light-transmitting part and the light-transmitting part. Similar to the linear scale 15, the light transmitting portion transmits light, and the non-light transmitting portion does not transmit light.

  The rotary encoder 24 is an optical sensor having a light projecting element and a light receiving element that face each other so as to sandwich the left and right surfaces of the rotary scale 23. The rotary encoder 24 supplies the control unit 30 with two analog rectangular wave signals (A-phase signal and B-phase signal) that change depending on whether light is received by the light receiving element. Then, every time the PF drive roller 21 rotates forward under the drive of the PF motor 22 and the light emitted from the light projecting element of the rotary encoder 24 toward the light receiving element is blocked by the non-light transmitting portion of the rotary scale 23, The level of the rectangular wave signal output from the rotary encoder 24 is switched from the low level to the high level. Therefore, the position on the stroke of the PF driving roller 21 is determined based on the number of pulses of the rectangular wave signal supplied from the rotary encoder 24, and the speed of the PF driving roller 21 is determined based on the period of the rectangular wave signal. It is possible.

  The CR motor 14 and the PF motor 22 are DC motors. These two motors 14 and 22 drive the driving pulley 11 and the driving roller 21 that are driven objects by repeating intermittent rotation while synchronizing with each other under the control of the control unit 30, and thereby the paper Support the formation of images.

  2A and 2B are diagrams showing how the motors 14 and 22 cooperate when forming an image on a single sheet. In both figures, the vertical axis represents the rotational speed of the motors 14 and 22, and the horizontal axis represents the drive time of the motors 14 and 22. The driving amounts of both the motors 14 and 22 correspond to the rotational distance of the driving roller 21 and the movement distance of the carriage 17 that are the objects to be driven. For convenience of illustration, the scale of the horizontal axis in FIG. 2B is smaller than that in FIG. In FIG. 2B, the positive / negative scale on the vertical axis indicates that the movement direction of the carriage 17 is opposite.

  As shown in FIG. 2A, when the print data indicating the image drawing content is supplied from the personal computer, the PF motor 22 in the non-rotating state (speed = 0) reaches the predetermined upper limit speed. It is accelerated almost proportionally. The PF motor 22 that has been accelerated to the upper limit speed continues to rotate for a while at the rotation speed, and then is decelerated approximately proportionally until it reaches the non-rotation state. Then, by driving the driving roller 21 according to the series of rotations of the PF motor 22, the paper stored in the hopper is conveyed downstream until the leading end reaches the printing start position under the recording head 19. In the following description, a region where the motors 14 and 22 are accelerated from the non-rotating state to the upper limit speed is referred to as an “acceleration region”, and a region where the motor 14 and 22 is decelerated from the upper limit speed to the non-rotating state is referred to as a “deceleration region”. The area between them is called “constant speed area”. The driving amount from the beginning of the first acceleration area to the end of the deceleration area after the print data is supplied and the ratio of each area shown in FIG. 2A are the acceleration / deceleration characteristics of the PF motor 22. It is set in consideration of the relationship with the transport distance until the leading edge of the paper stored in the hopper reaches the print start position.

  As shown in FIG. 2B, when the PF motor 22 is not rotated at the end of the deceleration region and the conveyance of the paper is stopped at the print start position, the rotation is not performed until the acceleration starts again. The existing CR motor 14 rotates. Similar to the PF motor 22, the rotational speed of the CR motor 14 also changes as the drive amount increases from the acceleration region to the constant speed region and then to the deceleration region. Then, by driving the driving pulley 11 according to the rotation of the series of CR motors 14, the carriage 17 connected to the driving pulley 11 via the belt 13 moves from the moving left limit position toward the moving right limit position. . Further, while the carriage 17 is moving in a section corresponding to a constant speed region on the stroke from the movement left limit position to the movement right limit position, ink droplets are ejected from the recording head 19 toward the paper, and the image A sequence of dots corresponding to one line in the main scanning direction is formed.

    As shown in FIG. 2B, the rotation of the CR motor 14 from the start of the acceleration region to the end of the deceleration region is performed while the PF motor 22 is not rotating, and the rotation direction is opposite every time. become. Then, the carriage 17 that has moved to the moving right limit position by the driving of the drive pulley 11 according to the second rotation of the CR motor 14 moves toward the moving left limit position. Note that whether ink droplets are ejected while the carriage 17 returns from the movement right limit position to the movement left limit position depends on various customizations.

  When the CR motor 14 becomes non-rotating at the end of the second deceleration region and stops moving when the carriage 17 reaches the moving left limit position, the non-rotating PF motor 22 rotates again (see FIG. 2 (A)). The rotational speed of the PF motor 22 at this time also changes as the drive amount increases from the acceleration region to the constant speed region and then to the deceleration region. Then, by driving the driving roller 21 according to the series of rotations of the PF motor 22, the sheet at the print start position is conveyed downstream by a distance corresponding to one line in the sub-scanning direction of the image. The driving amount from the start end of the second acceleration area to the end of the deceleration area and the ratio of each area shown in FIG. 2A correspond to the acceleration / deceleration characteristics of the PF motor 22 and one line in the sub-scanning direction. It is set in consideration of the relationship with distance.

  Thereafter, the CR motor 14 and the PF motor 22 rotate alternately until the arrangement of dots corresponding to all the lines in the sub-scanning direction of the image has been recorded on the paper, so that the moving left limit position and the moving right limit position are changed. The reciprocating movement of the carriage 17 between them and the conveyance of the sheet at a distance corresponding to one line in the sub-scanning direction are repeated. When the arrangement of dots corresponding to the lowest line in the sub-scanning direction of the image is recorded on the paper, the PF motor 22 that has not been rotated rotates, and the paper on which the image has been formed is conveyed downstream. The paper is discharged directly to the front side of the chassis. The driving amount from the start of the acceleration region to the end of the deceleration region and the ratio of each region in the final rotation of the PF motor 22 are the acceleration / deceleration characteristics of the PF motor 22 and the transport distance necessary for paper discharge. It is set in consideration of the relationship.

  Here, the torque of the CR motor 14 and the PF motor 22 increases as the energized current increases, and decreases as the current decreases. Therefore, in principle, by controlling the amount of current supplied to the CR motor 14 and the PF motor 22, both the motors 14 and 22 are set as shown in FIGS. 2 (A) and 2 (B). It is possible to change the speed. However, the torques of the motors 14 and 22 necessary to obtain the planned speed are affected by the load of the driven object such as the driving roller 21, the driving pulley 11, the belt 13, and the carriage 17, and the cogging of the motor itself. Change each time. Therefore, the control unit 30 of the printer according to the present embodiment measures the actual speed of the driven object based on the rectangular wave signals supplied from the linear encoder 20 and the rotary encoder 24, and stores the target speed table 90 (described later) in advance. PID control, which is one of feedback controls for adjusting the amount of current supplied to the motors 14 and 22 so as to converge the actual speed to the set target speed, is incorporated. Details of this PID control will be described later.

  In FIG. 1, the control unit 30 includes a motor driver 31, an interface circuit 35 (corresponding to “designating means”, “selection receiving means”, and “speed designation means”), a recording head control circuit 36, and a CPU (Central Processing Unit) 37. RAM (Random Access Memory) 38, ROM (Read Only Memory) 39, EEPROM (Electrically Erasable Programmable Read-Only Memory) 40, ASIC (Application Specific Integrated Circuit) 41, and head thermistor 80 (corresponding to "measuring means") Have

  The motor driver 31 outputs the output voltage of a DC power supply (not shown) to one of the CR motor 14 and the PF motor 22 according to a PWM (Pulse Width Modulation) signal supplied to itself. Applied as a pulse.

  The PWM signal is a rectangular wave whose period is constant and in which the ratio of the high level time and the low level time in one period changes. The proportion of the high level time in one cycle of the PWM signal is called “duty ratio”. When the duty ratio of the PWM signal supplied to the motor driver 31 is increased, the amount of current supplied to the CR motor 14 or the PF motor 22 increases, and a larger torque can be obtained.

  The interface circuit 35 receives print data and mode selection data indicating a mode selected through an interface screen of a personal computer (not shown). The recording head control circuit 36 supplies a signal for instructing ejection of ink droplets to the recording head 19 based on the interpretation of the print data. While using the RAM 38 as a work area, the CPU 37 refers to data stored in the ROM 39 and the EEPROM 40 and executes various programs stored in those memories. The ROM 39 stores a relatively simple program such as IPL (Initial Program Loader). The EEPROM 40 has a control program describing a control procedure from when print data is supplied to the interface circuit 35 until an image indicated by the print data is recorded on a sheet, and each of a plurality of target speed tables 90 (see FIG. 3). A set for each mode and a threshold value setting table 71 forming a part of a pause control unit 70 described later are stored.

  The target speed table 90 is a table that supports PID control of the CR motor 14 and the PF motor 22. Each set of the target speed table 90 corresponding to each of the default mode, the dedicated paper photo mode, and the plain paper draft mode is a table referred to when the paper is transported from the hopper to the print start position (hereinafter referred to as “first” as appropriate). A target speed table 90a "), a table referred to when the carriage 17 is moved from the moving left limit position to the movement right limit position (hereinafter referred to as" second target speed table 90b "as appropriate), and the carriage 17 A table (hereinafter referred to as “third target speed table 90c” as appropriate) that is referred to when moving the sheet from the moving right limit position to the moving left limit position, and the sheet is conveyed by a distance corresponding to one line in the sub-scanning direction. Table (referred to as “fourth target speed table 90d” where appropriate) and a sheet that is referred to when transporting paper to the front side of the chassis. Table (hereinafter, appropriately referred to as "fifth target speed table 90e") is a collection of. Each table 90a, 90b, 90c, 90d, 90e is each starting path of the acceleration target region shown in FIGS. 2A and 2B, that is, each line to be driven that is driven according to the rotation of the motors 14, 22. Each target position obtained by equally dividing the path from the starting point to the stop position at the end of the deceleration region and the target speed when the driven object reaches the target position is a large residual distance to the stop position. They are arranged in order. When the interface circuit 35 receives the print data, these tables are sequentially specified as reference objects, and the rotations of the CR motor 14 and the PF motor 22 are controlled according to the contents of the table that is the reference object.

  A set of individual target speed tables 90 is prepared for each of the default mode, the dedicated paper photo mode, and the plain paper draft mode. The size of the upper limit speed of the constant speed area and the acceleration area are set for each mode. This is because it is necessary to change the drive amount setting between the start end of the motor and the end of the deceleration region. As shown at the beginning, in the dedicated paper photo mode, a high-density dot array is recorded, so the transport distance corresponding to one line in the sub-scanning direction of the paper is shorter than in the default mode, and the carriage 17 is reciprocated. Need to move slower than the default mode. On the other hand, in the plain paper draft mode, since a low-density dot array is recorded, the transport distance corresponding to one line in the sub-scanning direction of the paper is made longer than in the default mode, and the speed of reciprocation of the carriage 17 is increased. Need to be faster than the default mode.

  The head thermistor 80 is provided in the vicinity of the recording head control circuit 36 and supplies a signal indicating the temperature measured by itself to the control unit 30.

  The control unit 30 logically implements the DC unit 50 by cooperating a part of the resources of the RAM 38 that expands the control program of the EEPROM 40, the CPU 37 that executes the RAM 38, and the ASIC 41. The RAM 38 and the CPU 37 are shared. By operating, the pause control unit 70 is logically realized. The DC unit 50 is a module that controls PID control. The pause control unit 70 is a module that controls pause control. The pause control is based on the magnitude relationship between the temperature measured by the head thermistor 80 and the threshold value, and the presence or absence of an overheating state of both the motors 14 and 22 is determined. In this control, the rotations of 14 and 22 are stopped.

  FIG. 3 is a diagram illustrating a logical configuration of each unit forming the DC unit 50 and the sleep control unit 70. The DC unit 50 includes a position calculating unit 51, a speed calculating unit 52, a position deviation calculating unit 53, a target speed specifying unit 54, a speed deviation calculating unit 55, a proportional element 56, an integrating element 57, a differentiating element 58, and a control value adding unit 62. , A PWM signal output unit 63, and a selector 64. In addition, the pause control unit 70 includes a threshold setting table 71, a pause control unit 72, a table specifying unit 76, and a delay unit 77.

  The function of each part constituting the DC unit 50 will be described. A rectangular wave signal output from one of the linear encoder 20 and the rotary encoder 24 is supplied to the position calculation unit 51 and the speed calculation unit 52. A selector 64 is inserted between the encoders 20 and 24 and the position calculation unit 51 and the speed calculation unit 52. The selector 64 is supplied with a signal for specifying a table to be referred to from a pause control unit 70 described later. The selector 64 receives the rectangular wave signal output from the linear encoder 20 while the second target speed table 90b or the third target speed table 90c, which is a table for driving the carriage 17, is a reference target. It supplies to both the position calculating part 51 and the speed calculating part 52. On the other hand, while the first target speed table 90a, the fourth target speed table 90d, or the fifth target speed table 90e, which is a table for driving the PF drive roller 21, is a reference target, the rotary encoder 24 is used. The rectangular wave signal output from is supplied to both of them.

  The position calculation unit 51 specifies the drive amount of the driven object based on the count number of the pitch of the rectangular wave signal supplied from the encoders 20 and 24 via the selector 64, and positions the signal indicating the specified drive amount. It supplies to the deviation calculating part 53. When the linear encoder 20 is selected as the supply source of the rectangular wave signal, the drive amount specified by the position calculation unit 51 based on the rectangular wave signal is from the movement left limit position to the movement right limit position or the movement right limit. This corresponds to the distance from the starting position on the stroke of the carriage 17 from the position to the moving left limit position. On the other hand, when the rotary encoder 24 is selected as the supply source of the rectangular wave signal, the driving amount specified by the position calculation unit 51 based on the rectangular wave signal corresponds to the distance from the starting position of the rotation of the driving roller 21. To do.

  The speed calculation unit 52 specifies the actual driving speed of the driven object based on the period of the rectangular wave signal supplied from the encoders 20 and 24 via the selector 64, and outputs a signal indicating the specified actual speed as a speed deviation. It supplies to the calculating part 55. When the linear encoder 20 is selected as the supply source of the rectangular wave signal, the actual speed specified by the speed calculation unit 52 based on the rectangular wave signal is the actual speed of the carriage 17 moving in the right or left direction. Equivalent to. On the other hand, when the rotary encoder 24 is selected as the supply source of the rectangular wave signal, the actual speed specified by the speed calculation unit 52 based on the rectangular wave signal corresponds to the actual speed of rotation of the drive roller 21.

  The position deviation calculator 53 is supplied with a signal indicating the driving amount from the position calculator 51 and a signal indicating the target stop position from the target speed table 90 to be referred to. For example, the target stop position while the first target speed table 90a is the reference target corresponds to the position where the arrival at the end of the first deceleration region in FIG. The position deviation calculation unit 53 obtains a position deviation between the current position of the driven target specified based on the drive amount indicated by the signal supplied from the position calculation unit 51 and the target stop position, and indicates the position deviation. Is supplied to the target speed specifying unit 54. The position deviation calculated by the position deviation calculation unit 53 corresponds to the remaining distance to the target stop position.

  The target speed specifying unit 54 is supplied with a signal indicating a position deviation from the position deviation calculating unit 53 and a signal specifying the reference target target speed table 90 from the pause control unit 70. The target speed specifying unit 54 specifies the target speed table 90 to be referred to indicated by the signal. Then, based on the target speed table 90 that is a reference target, the target speed corresponding to the position deviation indicated by the signal supplied from the position deviation calculating section 53 is specified, and the signal indicating the specified target speed is set as the speed deviation calculating section. 55 is supplied.

  The speed deviation calculating unit 55 is supplied with a signal indicating the actual speed from the speed calculating unit 52 and a signal indicating the target speed from the target speed specifying unit 54. The speed deviation calculating unit 55 obtains a speed deviation between the actual speed and the target speed indicated by these signals, and supplies a signal indicating the obtained speed deviation to each of the proportional element 56, the integral element 57, and the derivative element 58.

A signal indicating a speed deviation is supplied from the speed deviation calculation unit 55 to the proportional element 56, the integral element 57, and the derivative element 58, respectively. The proportional element 56 performs the calculation of the first term of the following general formula (1) of PID control on the signal supplied from the speed deviation calculation unit 55 and controls the signal indicating the proportional control value obtained as a result of the calculation. The value is supplied to the value adding unit 62. The integration element 57 performs the calculation of the second term of the expression (1) on the signal supplied from the speed deviation calculation unit 55, and supplies a signal indicating the integration control value obtained as the calculation result to the control value addition unit 62. . The differentiation element 58 performs the calculation of the third term of the expression (1) on the signal supplied from the speed deviation calculation unit 55 and supplies a signal indicating the differential control value obtained as the calculation result to the control value addition unit 62. . In the following equation (1), Δv (t) represents a value of a signal input from the speed deviation calculation unit 55 in synchronization with the clock timing t. In addition, the constants of the proportional gain K _P , the integral gain K _i , and the differential gain K _d in Expression (1) are optimized using a known method such as a step response method or a limit sensitivity method.

  The control value adding unit 62 adds the control values indicated by the signals supplied from the proportional element 56, the integrating element 57, and the differentiating element 58, and outputs a signal indicating the sum of the control values obtained by the addition to the PWM signal output unit 63. To supply. The PWM signal output unit 63 outputs a PWM signal having a duty ratio obtained by converting the sum of the control values supplied from the control value adding unit 62. The PWM signal output from the PWM signal output unit 63 is supplied to the motor driver 31.

  As described above, the torque of the CR motor 14 and the PF motor 22 increases as the duty ratio of the PWM signal supplied to the motor driver 31 increases, and the torque of the motors 14 and 22 decreases as the duty ratio decreases. Street.

  Next, the function of each part constituting the suspension control unit 70 will be described. FIG. 4 is a diagram illustrating a data structure of the threshold setting table 71. As shown in FIG. 4, this table 71 is divided into three categories, ie, “high load”, “medium load”, “low load” (“ This is a collection of records corresponding to “load data”. The measurement value is a value serving as an index indicating the magnitude of the load of the PF motor 22, and is measured according to the procedure described later each time the printer is turned on. Each record has fields of “plain paper draft mode”, “default mode”, and “dedicated paper photo mode” (corresponding to “speed data”), which are three modes that can be selected by the printer. Each field stores each threshold value used for comparison with the temperature measured by the head thermistor 80. That is, this table 71 stores each combination of mode and load and a threshold value in association with each other.

  In FIG. 3, the pause controller 72 is supplied with a signal indicating the temperature from the head thermistor 80 and a signal indicating the mode selected through the interface screen of a personal computer (not shown) from the interface circuit 35. The Further, the PWM signal output from the PWM signal output unit 63 is supplied. The pause control unit 72 measures a measurement value each time the power is turned on, and obtains a threshold value corresponding to a combination of a category corresponding to the measurement value and a mode selected at the time of measurement from the threshold setting table 71. After the threshold is acquired, the threshold is compared with the temperature supplied from the head thermistor 80, and a signal instructing the pause is supplied to the delay unit 77 every time the temperature exceeds the threshold.

  A signal indicating the position deviation is supplied from the position deviation calculating unit 53 to the table specifying unit 76. The table specifying unit 76 specifies the target speed table 90 to be the next reference target every time the position deviation indicated by the signal becomes zero, that is, every time the driven target of the motors 14 and 22 reaches the target position. Output a signal. Which of the default mode, the dedicated paper photo mode, and the plain paper draft mode is specified depends on the selection through the interface screen. That is, in this printer, the ratio of the acceleration area, the constant speed area, and the deceleration area and the size of the upper limit speed when the motors 14 and 22 are rotated are indirectly specified through the mode selection. The signal output from the table specifying unit 76 is supplied to the target speed specifying unit 54 and the selector 64 via the delay unit 77. When a signal instructing a pause is supplied from the pause controller 72, the delay unit 77 subsequently delays a signal passing through the delay unit 77 by a predetermined time. If the signal output from the table specifying unit 76 is delayed when passing through the delay unit 77, the target speed specifying unit 54 delays the specification of a new reference target table and the selector 64. Then, if the specification of a new reference target table and the switching of the selector 64 are delayed, the start timing of the next rotation of the motors 14 and 22 is delayed by that amount, and the heat dissipation of the motors 14 and 22 is promoted.

  FIG. 5 is a flowchart showing processing executed by the suspension control unit 72. A series of processing shown in FIG. 5 is started when the printer is turned on.

  When the printer is turned on, the pause control unit 72 measures the measurement value and determines whether the measurement value falls within a high load, medium load, or low load range (S100). The measurement value is a duty ratio of the PWM signal output from the PWM signal output unit 63 while the driving roller 21 drives the section corresponding to the constant speed region, and is obtained according to the following procedure. First, a signal instructing specification of the first target speed table 90a for the default mode is supplied to the table specifying unit 76, the PF motor 22 is rotated, and the driving roller 21 is driven. The duty value of the PWM signal output from the PWM signal output unit 63 while the drive roller 21 drives the section corresponding to the first constant speed area in FIG. 2A, that is, the PF motor 22 is set in the constant speed area. The average value of the duty ratio required to rotate at the upper limit speed is obtained. The average value of the obtained duty ratio is the measurement value.

  The measurement value obtained in this way becomes an index indicating the magnitude of the load of the PF motor 22 for the following reason. As described above, the DC unit 50, which is a module that controls PID control, adjusts the amount of current supplied to the PF motor 22 so that the actual speed of the PF motor 22 converges to the target speed of the target speed table 90. The adjustment of the current supply amount is performed by increasing or decreasing the duty ratio of the PWM signal. Therefore, the larger the load of the PF motor 22, the greater the amount of current supplied to rotate the PF motor 22 at the target speed, and the greater the duty ratio of the PWM signal for obtaining the amount of supply. From such correlation between the load of the PF motor 22 and the duty ratio, the average value of the duty ratio in the constant speed region can be handled as an index indicating the magnitude of the load of the PF motor 22.

  In step S100, the hibernation control unit 72 that has determined which range of the high load, medium load, and low load corresponds to the measurement value, the combination of the selected mode and the category to which the measurement value corresponds. And the threshold value stored in the threshold value setting table 71 in association with (S110).

  When the interface circuit 35 receives the print data from the personal computer after the processing of step S100 and step S110 is performed, a signal for specifying the target speed table 90 to be referred to is sequentially output from the table specifying unit 76. The motors 14 and 22 rotate intermittently according to a target speed table 90 specified by these signals. Then, the series of rotations and the ejection of ink by the recording head 19 are performed in synchronization, whereby an image corresponding to the print data is formed on the paper.

  When a signal indicating temperature is supplied from the head thermistor 80 while a series of rotations of the motors 14 and 22 are performed (S120: Yes), the pause control unit 72 acquires the temperature indicated by the signal and the step S100. The magnitude relation between the threshold values is determined (S130), and when it is determined that the temperature exceeds the threshold value (S130: Yes), a signal instructing the pause is supplied to the delay unit 77 (S140). Then, the start timing of the subsequent rotation of the motors 14 and 22 is delayed by a predetermined time, and the heat dissipation of the motors 14 and 22 is promoted. After executing step S140, the pause control unit 72 returns to step S120 and waits for the supply of a new signal from the head thermistor 80. If it is determined in step S130 that the temperature does not exceed the threshold value (S130: No), the process returns to step S120 without executing step S140.

  The threshold value setting table 71 of the ink jet printer according to the present embodiment described above includes the threshold values used for comparison with the temperature of the head thermistor 80, the dedicated paper photo mode, the default mode, and the plain paper draft mode. These are stored in association with combinations of loads, medium loads, and low loads. The printer compares the threshold value acquired from the threshold setting table 71 with the magnitude of the temperature indicated by the signal supplied from the head thermistor 80, and stops the rotation of the motors 14 and 22 when the temperature exceeds the threshold value. It has become. Therefore, in the design stage of the ink jet printer, a test operation is performed under each condition that combines the mode and the load, and each threshold value calculated based on the result is stored in the threshold value setting table 71, whereby the motor 14. , 22 can be executed at an optimal timing with the frequency of pause control necessary to prevent the breakage.

  The setting of the threshold value that can optimize the timing of this pause control will be further described in detail. FIG. 6A is a diagram showing changes in the temperatures of the head thermistor 80 and the PF motor 22 when image formation is continuously performed in both the dedicated paper photo mode and the plain paper draft mode. Note that the temperature measured by the head thermistor 80 substantially matches the temperature of the recording head 19 itself, and the temperature of the PF motor 22 is a value measured by bringing a measuring instrument into contact with the PF motor 22. Further, it is assumed that the load of the PF motor 22 is the same in both the dedicated paper photo mode and the plain paper draft mode.

  Referring to the temperature of the head thermistor 80 and the temperature of the PF motor 22 in the dedicated paper photo mode shown in FIG. 6A, the temperatures of the head thermistor 80 and the PF motor 22 increase as the image formation time elapses. The slope of the temperature rise curve of the head thermistor 80 is higher than that of the PF motor 22. On the other hand, referring to the temperature of the head thermistor 80 and the temperature of the PF motor 22 in the plain paper draft mode shown in FIG. 6A, as in the dedicated paper photo mode, the temperature increases as the image formation time elapses. However, the temperature rise curve of the PF motor 22 is higher than that of the head thermistor 80. Therefore, in the dedicated paper photo mode, the temperature of the head thermistor 80 is increased to a temperature T1 that is higher by d1 than the upper limit temperature (hereinafter referred to as “PF motor upper limit temperature”) that does not cause damage to the PF motor 22. While the PF motor 22 can be prevented from being damaged by applying the pause control when the temperature rises, in the plain paper draft mode, the pause control is performed when the temperature of the head thermistor 80 rises to a temperature T2 that is lower than the PF motor upper limit temperature by d2. It can be seen that the damage to the PF motor 22 cannot be prevented without applying.

  FIG. 6B shows a case where the load of the PF motor 22 is set to an upper limit (large load) and a lower limit (low load) at which the load can be changed, and image formation is continuously performed in the dedicated paper photo mode. FIG. 6 is a diagram showing a change in temperature of the head thermistor 80 and the PF motor 22. In addition, it is the same as that of FIG. 6A that the temperature of the PF motor 22 is a value actually measured by bringing a measuring instrument into contact.

  Referring to the temperature of the head thermistor 80 shown in FIG. 6B, the temperature is the same regardless of the load of the PF motor 22. This is considered to be because the drive amount of the piezoelectric element that is the main cause of heat storage of the recording head 19 does not depend on the load of the PF motor 22. On the other hand, the temperature of the PF motor 22 is lower than the head thermistor 80 when the load is the lower limit (low load), and the temperature is higher than the head thermistor 80 when the load is the upper limit (high load). Yes. From this, when the load of the PF motor 22 is reduced to near its lower limit, the PF motor 22 is stopped when the temperature of the head thermistor 80 rises to a temperature T3 that is higher by d3 than the upper limit temperature of the PF motor. While the motor 22 can be prevented from being damaged, when the load of the PF motor 22 is increased to near its upper limit, the head thermistor 80 is stopped when the temperature of the head thermistor 80 rises to a temperature T4 lower by d4 than the upper limit temperature of the PF motor. It can be seen that damage to the PF motor 22 cannot be prevented without control.

  Thus, there is a correlation between the temperature of the head thermistor 80 and the temperature of the PF motor 22, and the temperature T of the head thermistor 80 that serves as a trigger for restricting the rest of the PF motor 22 depends on the load and mode of the PF motor 22. It moves up and down depending on. Although illustration is omitted, there is a similar correlation between the temperature of the head thermistor 80 and the temperature of the CR motor 14, and the temperature T of the head thermistor 80 serving as a trigger for restricting the rest of the CR motor 14 is also It moves up and down depending on the load and mode of the CR motor 14. Therefore, a test operation is performed under each condition with a different mode and load combination, and the threshold value is set with the temperature T of the head thermistor 80 when either the PF motor 22 or the CR motor 14 reaches the upper limit temperature as a threshold value. By storing the setting in the setting table 71, it is possible to execute the pause control at a frequency necessary to prevent the motors 14 and 22 from being damaged at an optimal timing.

(Other embodiments)
The present invention can be modified in various ways.

  The ink jet printer according to the above-described embodiment includes two motors, namely, a CR motor 14 whose driving target is the driving pulley 11, the driven pulley 12, the belt 13, and the carriage 17, and a PF motor 22 whose driving target is the driving roller 21. Although a motor is mounted, all of those driven objects may be driven by one motor.

  In the above embodiment, the target speed tables 90a, 90d, and 90e that describe how to change the target speed of rotation of the PF motor 22, and the target speed table that describes how to change the target speed of rotation of the CR motor 14 are described. 90b and 90c are sequentially specified as reference targets, and the rotation of the motors 14 and 22 is PID controlled as the target speed tables 90a, 90b, 90c, 90d, and 90e that are the reference targets. In the pause control, both the motors 14 and 22 are paused by delaying the switching timing of the target speed tables 90a, 90b, 90c, 90d, and 90e to be referred to. On the other hand, the suspension control may be performed according to another procedure. For example, a signal indicating pause time is supplied to the target speed specifying unit 54 from the pause determination unit 75 that has determined that a pause is required, and the target speed specifying unit 54 sets a new target speed over the time indicated by the signal. The specification of the table 90a may be delayed.

  The ink jet printer according to the above embodiment obtains a measurement value indicating the load of the PF motor 22 and acquires a threshold value corresponding to the combination of the measurement value and the mode from the threshold value setting table 71. On the other hand, a measurement value indicating the load of the CR motor 14 may be obtained, and a threshold value corresponding to the combination of the measurement value and the mode may be acquired from the threshold value setting table 71.

  In the ink jet printer according to the above-described embodiment, the rotation speed of the motors 14 and 22 at the time of forming an image is indirectly specified through selection of a mode on the interface screen. On the other hand, the rotation speed of the icon motors 14 and 22 at the time of forming an image may be directly designated through an operation of a volume icon or the like provided on the interface screen.

  In the above embodiment, the present invention is applied to PID control of the CR motor 14 and the PF motor 22 mounted on the ink jet printer. On the other hand, for example, the present invention may be applied to another type of apparatus in which a motor that requires PID control is mounted, such as a motor that transports the carriage 17 of the scanner apparatus.

  The controller 30 of the ink jet printer according to the above-described embodiment is configured to accelerate the other motor after the speed is reduced until one of the CR motor 14 and the PF motor 22 is not rotated. . That is, the control unit 30 is configured to intermittently drive the CR motor 14 and the PF motor 22 so that the respective driving times do not overlap. On the other hand, the CR motor 14 may start acceleration at a slightly earlier timing than the PF motor 22 that has started decelerating becomes non-rotating. Similarly, the PF motor 22 may start acceleration at a slightly earlier timing than the CR motor 14 that has started decelerating becomes non-rotating.

  In addition, the driving of the CR motor 14 of the ink jet printer according to the above-described embodiment is repeated twice or more while the PF motor 22 is in a non-rotating state, that is, from when the conveyance of the paper is stopped until the conveyance is started again. You may be made to do.

1 is a diagram illustrating a schematic hardware configuration of an ink jet printer according to an embodiment of the present invention. It is a figure which shows the mode of cooperation of the motor at the time of forming an image on the paper of 1 sheet. It is a figure which shows the logical structure of each part which makes DC unit and a dormant control unit. It is a figure which shows the data structure of the threshold value setting table. It is a flowchart which shows the process which a pause control part performs. It is a figure which shows the relationship between the temperature of a head thermistor, and the temperature of a PF motor.

Explanation of symbols

11 ... Driving pulley (corresponding to "second driven body"), 12 ... Driven pulley (corresponding to "second driven body"), 13 ... Belt (corresponding to "second driven body"), 14 ... CR motor (corresponding to "second motor"), 15 ... linear scale, 16 ... guide shaft, 17 ... carriage (corresponding to "second driven member"), 18 ... ink cartridge, 19 ... recording head , 20 ... Linear encoder, 21 ... Driving roller (corresponding to "first driven body"), 22 ... PF motor (corresponding to "first motor"), 23 ... Rotary scale, 24 ... Rotary encoder, 25 ... Left side wall, 26 ... right side wall, 27 ... rear side wall, 30 ... control unit (corresponding to "specifying means", "determination means", "control means", "detection means"), 31 ... first motor driver, 33 ... Second motor driver, 35 ... interface times (Corresponding to “designating means”, “selection accepting means”, “speed designating means”), 36... Print head control circuit, 37... CPU, 38... RAM, 39 ... ROM, 40. ... Position calculation section, 52 ... Speed calculation section, 53 ... Position deviation calculation section, 54 ... Target speed specification section, 55 ... Speed deviation calculation section, 56 ... Proportional element, 57 ... Integration element, 58 ... Differential element, 62 ... Control Value adding unit 63 ... PWM signal output unit 64 ... Selector 70 ... Pause control unit 71 ... Threshold setting table 72 ... Pause control unit 76 ... Table specifying unit 77 ... Delay unit 80 ... Head thermistor (" Equivalent to "measuring means"), 90 ... target speed table

Claims (6)

A driven body;
A motor that applies driving force to the driven body by rotation according to the amount of power supplied to itself;
Measuring means for measuring the temperature of the driven body;
A memory storing each threshold value used for comparison with the temperature of the driven body in association with each combination of speed data indicating speed and load data indicating load;
A specification means for specifying the speed,
A specifying means for specifying the load of the motor;
Judgment that specifies a threshold value stored in the memory in association with a combination of the speed data indicating the specified speed and the load data indicating the specified load, and determines whether the measured temperature exceeds the threshold value Means,
Means for intermittently driving the driven body through supply of electric power to the motor, the driving body being driven at the specified speed for each intermittent drive; Control means for adjusting the amount of power supplied to the motor and delaying the start timing of driving of the driven body after the determination means determines that the temperature has exceeded a threshold; and
A motor control device comprising: A first driven body;
A first motor that applies a driving force to the first driven body by rotation according to the amount of power supplied to itself;
A second driven body;
A second motor that applies a driving force to the second driven body by rotation according to the amount of power supplied to itself;
Measuring means for measuring the temperature of the second driven body;
Each threshold value used for comparison with the temperature of the second driven body includes speed data indicating the driving speed of the first driven body and the second driven body, and the first driven body. A memory stored in association with each combination of load data indicating one or both of the body and the second driven body;
A specification means for specifying the speed,
Specifying means for specifying a load on one or both of the first motor and the second motor;
Judgment that specifies a threshold value stored in the memory in association with a combination of the speed data indicating the specified speed and the load data indicating the specified load, and determines whether the measured temperature exceeds the threshold value Means,
Means for intermittently driving each of the first driven body and the second driven body by supplying electric power to the first motor and the second motor, wherein Whenever the driven body or the second driven body is driven, the amount of electric power supplied to the motor that applies driving force to the driven body until the driven body to be driven is driven at the specified speed. Control means for delaying the start timing of driving of the first driven body or the second driven body after the determination means determines that the temperature has exceeded a threshold by a predetermined time;
A motor control device comprising: The first driven body is:
Having a roller for conveying a medium to be ejected of ink droplets;
The second driven body is:
A carriage that supports a recording head that ejects ink droplets, and a movement support mechanism that reciprocates the carriage in a direction orthogonal to the conveyance,
The measuring means measures the temperature of the recording head;
The motor control device according to claim 1, wherein the motor control device is a motor control device. Detecting means for detecting the speed of conveyance of the medium by the roller;
Further comprising
The specifying means is:
Identifying the load of the first motor based on the amount of power supplied to the first motor when the detection means detects the specified speed;
The motor control device according to claim 3. Detecting means for detecting the speed of movement of the carriage;
Further comprising
The specifying means is:
Identifying the load of the second motor based on the amount of power supplied to the second motor when the detection means detects the specified speed;
The motor control device according to claim 3. The designation means is:
Selection accepting means for accepting selection of one of a plurality of modes respectively associated with each combination of the speed of the first driven body and the speed of the second driven body;
Speed specifying means for specifying a combination of speeds associated with the specified mode;
The motor control device according to claim 1, comprising:

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