JP2009073180A - Printer and printer motor control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conduct motor suspension control without giving an impression of the occurrence of a defect and trouble to a user. <P>SOLUTION: The printer includes: a motor for giving driving force to a driven unit through own rotation; a calculating means for calculating a heat amount correlation value being a value having correlation with the heat amount accumulated in the motor, and, as a means for intermittently rotating the motor by leaving the motor for a predetermined interval; and a control means for shortening the length of its interval so that the number of times that the calculated heat amount correlation value exceeds a threshold value increases. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a printer and a printer motor control method.

  The ink jet printer has a CR (Carriage) motor that reciprocates the carriage in the scanning direction, and a PF (Paper Feed) that transports the paper stored in the paper feed tray to the paper discharge tray via the carriage. Various DC motors such as motors are installed. 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. The mechanism of the motor pause control to be carried is mounted (for example, refer to Patent Document 1).

JP 2003-079178

  By the way, most of the motor pause control of an ink jet printer calculates the estimated temperature of the motor based on the PWM (Pulse Width Modulation) duty ratio that determines the effective current value of the motor and its current supply amount, and the estimated temperature exceeds the threshold value. Each time, the procedure is such that a pause is inserted between the temporary stop and restart of the motor. And the threshold value and time length which are provided for comparison with estimated temperature are constant. On the other hand, the motor is more likely to accumulate heat as the driven roller or pulley becomes deteriorated over time and the load becomes heavier. For this reason, there is a problem that the longer the use period of the ink jet printer, the more frequently the suspension control is entered, giving the user the impression that a malfunction or failure has occurred.

  The present invention has been devised under such a background, and an object of the present invention is to provide a mechanism capable of performing motor stop control without giving a user an impression that a malfunction or failure has occurred. .

  A printer according to a preferred aspect of the present invention calculates a calorie correlation value, which is a value correlated with the amount of heat accumulated in the motor, and a motor that gives driving force to the driven body through its rotation. And a control means for intermittently rotating the motor with a predetermined interval, and a control means for shortening the length of the interval as the number of times the calculated heat quantity correlation value exceeds the first threshold increases. . According to this, it is possible to prevent damage to the motor without giving the user an impression that a problem or failure has occurred.

  In addition to the above-described invention, the first threshold may be individually counted at least for each print mode or for each image data. In this way, it is possible to prevent an increase in the number of times exceeding the first threshold in a specific print mode or specific image data due to the influence of another print mode or other image data.

  Moreover, in addition to the above-mentioned invention, it is a table in which the second threshold value used for comparison with the calorie correlation value is associated with time data indicating the interval time, and the larger second threshold value indicates the longer time. A memory storing a table associated with the time data, and the control means counts the number of times that the calculated heat quantity correlation value exceeds the first threshold, and the number of times the count means counts up. Until the preset number of times is reached, the largest second threshold value is specified from the second threshold values of the table, and after the number of times of counting reaches the set number of times, the second threshold value of the table is selected. A threshold value specifying unit that specifies a second threshold value that is smaller than the largest second threshold value, and a determination that determines whether the calculated heat quantity correlation value exceeds the second threshold value specified by the threshold value specifying unit When the determining means determines that the heat value correlation value exceeds the second threshold, the time data stored in the table in association with the second threshold specified by the threshold specifying means is specified, and the time data indicates And a rotation control means for rotating the motor at intervals of time.

  According to this, it is possible to fix the threshold and the length of the interval until the count reaches the preset number of times, and gradually decrease the second threshold and the length of the interval after reaching the number of times. it can.

  In addition to the above-described invention, when the counting means counts up the number of times that the calculated heat quantity correlation value exceeds the first threshold value, a heat quantity correlation value that is lower than another third threshold value that is smaller than the first threshold value is calculated. Further count up may be stopped until calculated by the means. According to this, it is possible to accurately count the actual number of times that the motor has been stopped, and to use the printer usage estimated from the count value for later model development.

  Also, the printer motor control method according to the preferred embodiment of the present invention is a calculation for calculating a heat quantity correlation value that is a value correlated with the heat quantity accumulated in the motor that gives driving force to the driven body through its own rotation. And a control step of rotating the motor intermittently with a predetermined interval, and shortening the interval length as the number of times the calculated heat quantity correlation value exceeds the first threshold increases. According to this, it is possible to prevent damage to the motor without giving the user an impression that a problem or failure has occurred.

    Further, a printer according to a preferred aspect of the present invention has a correlation with a driven body, a motor that gives a driving force to the driven body through its own rotation, and the amount of heat accumulated in the motor, and drives the motor. The first threshold setting means for setting the first threshold value to be stopped, the counting means for counting the number of times the first threshold value is reached, and the amount of heat accumulated in the motor have a correlation with each other and the heat generation restriction of the motor is started. A second calculating unit that calculates two thresholds; and a threshold specifying unit that specifies to decrease the second threshold as the number of counts of the first threshold in the counting unit increases.

  According to this, when the count number of the first threshold value in the counting means increases, the second threshold value for starting the heat generation restriction is lowered, so that the temperature entering the heat production restriction of the motor is lowered. Therefore, as the use frequency increases, the motor can be prevented from being damaged (burned out).

  In addition to the above-described invention, the first threshold may be individually counted at least for each print mode or for each image data. In this way, it is possible to prevent an increase in the number of times exceeding the first threshold in a specific print mode or specific image data due to the influence of another print mode or other image data.

  In addition to the above-described invention, the first threshold value may be set to an initial value when a predetermined condition is satisfied.

  In this way, when a predetermined condition is satisfied, the throughput of the printer can be improved, and the user is not given the impression that the performance has deteriorated.

(Embodiment of the Invention)
Embodiments of the present invention will be described below with reference to the drawings.

<About the overall configuration of the printer>
FIG. 1 is a diagram illustrating a schematic hardware configuration of an ink jet printer 10 according to the present embodiment. As shown in FIG. 1, the printer 10 includes a driving pulley 11 (corresponding to “driven body”), a driven pulley 12 (corresponding to “driven body”), a belt 13 (corresponding to “driven body”), CR motor 14, linear scale 15, guide shaft 16, carriage 17 (corresponding to “driven body”), ink cartridge 18, recording head 19, linear encoder 20, driving roller 21 (corresponding to “driven body”), PF The motor 22, the rotary scale 23, the rotary encoder 24, and the control unit 30 (corresponding to “calculation unit”, “second calculation unit”, and “control unit”) are included. 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 the paper P (corresponding to “medium”) in the front-rear direction. A rear side wall 27 is erected so as to connect the rear ends of the walls 25 and 26. 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 equal to the width of the conveyance path of the paper P. 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. A plurality of sheets of paper P can be accommodated in a hopper (not shown) 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. The right end 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 the left end is connected 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 end of the rotating shaft of the PF drive roller 21 is composed of a plurality of rectangular light-transmitting portions extending radially outward from the center of the disk-shaped plate, and adjacent light-transmitting portions. A structure is arranged in a ring with a predetermined interval between them. 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. Each time the driving roller 21 is rotated forward by a driving force from the PF motor 22 and light emitted from the light projecting element of the rotary encoder 24 toward the light receiving element is blocked by the non-transmissive 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 of the driving roller 21 on the stroke is determined based on the number of pulses of the rectangular wave signal supplied from the rotary encoder 24, and the speed of the driving roller 21 is determined based on the period of the rectangular wave signal. 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 Supports image formation on P.

  2A and 2B are diagrams showing how the motors 14 and 22 cooperate when forming an image on a single sheet P. FIG. 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 horizontal scale in FIG. 2B is smaller than that in FIG. 2A, and the vertical scale in FIG. 2B is opposite to that in FIG.

  As shown in FIG. 2A, when print data indicating image drawing contents is supplied from a personal computer (not shown), the PF motor 22 in a non-rotating state (speed = 0) It is accelerated almost proportionally until it reaches the upper speed limit. 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 P accommodated 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 P accommodated in the hopper reaches the print start position.

  As shown in FIG. 2B, when the PF motor 22 is in a non-rotating state at the end of the deceleration region and the conveyance of the paper P is stopped at the print start position, the rotation is not started until the acceleration starts again. The CR motor 14 was rotated. 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 P, An array of dots corresponding to one line in the main scanning direction of the image is formed.

  As shown in FIG. 2B, the rotation of the CR motor 14 from the beginning of the acceleration region to the end of the deceleration region is repeated twice between the time when the conveyance of the paper P stops and the time when the acceleration starts again. The direction of rotation of the second CR motor 14 is opposite to that of the first time. 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. The driving amount from the start end of the first acceleration region to the end of the deceleration region and the ratio of each region shown in FIG. 2B are the acceleration / deceleration characteristics, the movement right limit position, and the movement left limit of the CR motor 14. The driving amount from the start of the second acceleration region to the end of the deceleration region is the same as that of the first time. However, the ratio of the acceleration region, the constant speed region, and the deceleration region in the second rotation depends on circumstances such as whether ink droplets are ejected while the carriage 17 returns from the movement right limit position to the movement left limit position. Depending on the case, it may be different from the first one.

  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 paper P 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 P, whereby the moving left limit position and the moving right limit position The reciprocating movement of the carriage 17 and the conveyance of the paper P at a distance corresponding to one line in the sub-scanning direction are repeated. When the dot arrangement corresponding to the lowest line in the sub-scanning direction of the image is recorded on the paper P, the non-rotated PF motor 22 rotates and the image-formed paper P is conveyed downstream. Then, it is discharged as it is to the front side of the chassis. The drive 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 determined by the acceleration / deceleration characteristics of the PF motor 22 and the transport distance necessary for paper discharge. 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 required 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 10 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 it as a target speed table (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.

<About the printer control unit>
In FIG. 1, a control unit 30 includes a first motor driver 31, a second motor driver 33, an interface circuit 35, a recording head control circuit 36, a CPU (Central Processing Unit) 37, a RAM (Random Access Memory) 38, a ROM (Read It has an only memory (EEPROM) 39, an electrically erasable programmable read-only memory (EEPROM) 40, and an application specific integrated circuit (ASIC) 41.

  The first motor driver 31 applies the output voltage of a DC power supply (not shown) to the PF motor 22 as a pulse corresponding to a PWM (Pulse Width Modulation) signal supplied to the first motor driver 31. The PWM signal is a rectangular wave whose period is constant and 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 first motor driver 31 is increased, the amount of current supplied to the PF motor 22 is increased, and a larger torque can be obtained.

  The configuration of the second motor driver 33 is the same as that of the first motor driver 31, and the output voltage of a DC power supply (not shown) is applied to the CR motor 14 as a pulse corresponding to the PWM signal supplied to itself. When the duty ratio of the PWM signal supplied to the second motor driver 31 is increased, the amount of current supplied to the CR motor 14 is increased, and a larger torque can be obtained.

  The interface circuit 35 receives print data from 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 plurality of target speed tables 90 (see FIG. 3) in addition to a control program that describes 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 the paper P. ) Is stored.

  The plurality of target speed tables 90 are tables that support PID control of the CR motor 14 and the PF motor 22, and are referred to when the paper P is transported from the hopper to the print start position (hereinafter referred to as “first target as appropriate”). 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 from the movement right limit position to the movement left limit position and the sheet P are conveyed by a distance corresponding to one line in the sub-scanning direction. (Referred to below as “fourth target speed table 90d” as appropriate) and the paper P to be conveyed to the front side of the chassis. Buru (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 path to be driven that is driven according to the rotation of the motors 14, 21. Each position obtained by equally dividing the path from the starting point to the stop position at the end of the deceleration area and the target speed when the driven target reaches those positions are determined from those with a large remaining 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.

  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. By operating, the pause control unit 70 (corresponding to “counting means”, “threshold specifying means”, “first threshold setting means”, “determination means”, “rotation control means”) is logically realized. The DC unit 50 is a module that controls PID control. The pause control unit 70 is a module that performs motor pause control. The motor pause control is performed based on the effective current values (described later) of the CR motor 14 and the PF motor 22 to determine whether or not the motors 14 and 22 are overheated. 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 selectors 64 and 65. The sleep control unit 70 includes a sleep history storage unit 71, a sleep history update unit 72, a sleep time table 73, a current value calculation unit 74, a sleep determination unit 75, a table specification 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 leftward or leftward. 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. Further, the signal indicating the actual speed specified by the speed calculation unit 52 is also supplied to a current value calculation unit 74 of the pause control unit 70 described later.

  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 object specified based on the drive amount indicated by the signal supplied from the position calculation unit 51 and its target stop position, and calculates the obtained position deviation. The indicated signal 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 one of the first motor driver 31 and the second motor driver 33 and the current value calculation unit 74 of the pause control unit 70.

  A selector 65 is interposed between the PWM signal output unit 63 and the drivers 31 and 33. The selector 65 is supplied with a signal for specifying the reference target table from the pause control unit 70. The selector 65 supplies the PWM signal output from the PWM signal output unit 63 to the second motor driver 33 while the target speed tables 90 b and 90 c of the carriage 17 are being referenced, and the target speed of the PF drive roller 21. While the tables 90a, 90d, and 90e are the reference targets, the PWM signal output from the PWM signal output unit 63 is supplied to the first motor driver 31. The greater the duty ratio of the PWM signal supplied to the first motor driver 31 and the second motor driver 33, the greater the torque of the CR motor 14 and the PF motor 22, and the smaller the duty ratio, the torque of both the motors 14, 22 Is as described above.

  Next, the function of each part constituting the suspension control unit 70 will be described. The suspension history storage unit 71 stores a count value indicating the number of times that the suspension control of the motors 14 and 22 has been performed. The count value of the dormant history storage unit 71 is counted up by the dormant history update unit 72. Details of characteristic processing relating to the count up will be described later with reference to a flowchart. The downtime table 73 is a table in which each threshold value used for comparison with the estimated temperature of the motors 14 and 22 is associated with downtime data indicating the length of the downtime. Each pair of threshold value and pause time data in this table is a combination in which a larger threshold value and time data indicating a longer time are associated with each other.

The current value calculation unit 74 is supplied with a signal indicating the actual speed specified by the calculation unit 52 from the speed calculation unit 52 and the PWM signal output by the PWM signal output unit 63. The current value calculation unit 74 inputs the actual speed and duty ratio values obtained from these signals into the following calculation formula (2), whereby the instantaneous value of current flowing into the motor (hereinafter referred to as “current instantaneous value”). Calculate I _INS . In the calculation formula (2), V represents a constant corresponding to the output voltage of a DC power supply (not shown). Further, PWM Duty indicates a duty ratio obtained from a signal supplied from the PWM signal output unit 63, and MAX Duty indicates a constant corresponding to the upper limit value of the duty ratio. Further, Ke represents a constant corresponding to the counter electromotive voltage of the motor, and ω represents an actual speed obtained from a signal supplied from the speed calculation unit 52. R represents a constant corresponding to the internal resistance of the motors 14 and 22.

The current value calculation unit 74 obtains a total of a series of instantaneous current values I _INS obtained by calculation for a predetermined time (for example, 1 minute), and takes the square root of a value obtained by dividing the obtained total value by the time. A signal indicating the effective current value I _EFF obtained by the above is supplied to the pause determination unit 75.

When the signal is supplied from the current value calculation unit 74, the pause control unit 75 inputs the effective current value I _EFF indicated by the signal to the following calculation formula (3), thereby generating a heating value Q of the motors 14 and 22. Is calculated. If the estimated temperature (corresponding to the “calorific value correlation value”) obtained by reducing a predetermined heat release amount from the heat generation amount Q of the motors 14 and 22 exceeds a threshold value, the motors 14 and 22 are in an overheated state. The signal indicating the rest time of the motors 14 and 22 is supplied to the delay unit 77. As will be described later, the threshold value used for comparison with the estimated temperature and the length of the pause time depend on the count value stored in the pause history storage unit 71, that is, the number of pause controls already executed. fluctuate. In the following calculation formula (3), R represents the internal resistance of the motor, and t is a predetermined time (for example, 1 minute) required to obtain the total current instantaneous value I _INS . K is a count for converting a certain work into a calorific value.

  The function of the pause determination unit 75 will be described in further detail. When receiving a signal indicating the estimated temperature from the current value calculation unit 74, the pause determination unit 75 refers to the count value in the pause history storage unit 71. The pause determination unit 75 does not refer to the pause time table 73 while the count value of the pause history storage unit 71 is smaller than a preset number (for example, 256), and sets a threshold value (hereinafter, referred to as a default). (Referred to as “default threshold”) and the estimated temperature. When the estimated temperature exceeds the default threshold value, a signal indicating a pause time set as a default (hereinafter referred to as “default pause time”) is supplied to the delay unit 77. The size of the default threshold is the same as the largest threshold among the thresholds stored in the pause time table 73, and the default pause time is the pause time indicated by each pause time data stored in the pause time table 73. Same as the longest downtime. Furthermore, when the count value of the pause history storage unit 71 exceeds a preset number (for example, 256), the pause determination unit 75 specifies each threshold value in the pause time table 73 in order from the largest threshold value. When the estimated temperature exceeds the specified threshold value, the pause time data stored in the pause time table 73 in association with the threshold value is read, and the pause time signal indicated by the read pause time data is supplied to the delay unit 77. .

  Therefore, as shown in FIG. 4, the threshold value (default threshold value) used for comparison with the estimated temperature is constant until the count value of the pause history storage unit 71 reaches a preset number (for example, 256 times). On the other hand, when the count value of the pause history storage unit 71 exceeds a preset number, the threshold value used for comparison with the estimated temperature decreases. Furthermore, after the count value of the pause history storage unit 71 exceeds a preset number, the pause time when the estimated temperature exceeds the threshold value gradually decreases from the default pause time.

Note that the threshold value dT _MAX in FIG. 6 is the same value as the default threshold value (FIG. 4), and corresponds to the first threshold value. Further, the second threshold shown in FIG. 4 is a threshold for starting the heat generation limitation of the motors 14 and 22, and corresponds to the second threshold. This is as shown in FIG. 9. When the second threshold value (heat generation limit) is exceeded, the control unit is configured so that the temperature rise of the motors 14 and 22 until the threshold value dT _MAX is reached. The drive of the motors 14 and 22 is restricted by 30. The threshold value dT _OFF corresponds to the third threshold value.

  Returning to the description of FIG. 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. The signal output from the table specifying unit 76 is supplied to the target speed specifying unit 54 and the selectors 64 and 65 after being delayed by the delay unit 77. The amount of delay when the signal output from the table specifying unit 76 passes through the delay unit 77 corresponds to the delay time indicated by the signal supplied from the pause determination unit 75 to the delay unit 77. If the signal 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 switching of the selectors 64 and 65. Then, if the specification of a new reference target table and the switching of the selectors 64 and 65 are delayed, the time until the start of the next acceleration of the motors 14 and 22 (corresponding to the “interval”) becomes longer by the delay. Therefore, heat dissipation of the motors 14 and 22 is promoted.

The dormant history update unit 72 is set with three threshold values: a threshold value dT _MAX (corresponding to the first threshold value), a second threshold value shown in FIG. 4, and a threshold value dT _OFF (corresponding to the third threshold value). The threshold value dT _MAX is the same value as the default threshold value of the pause determination unit 75. In addition, the threshold value dT _MAX and the initial second threshold value are the same value. On the other hand, the threshold value dT _OFF is a value sufficiently lower than the threshold value dT _MAX . The pause history update unit 72 counts up the count value of the pause history storage unit 71 every time the estimated temperature indicated by the signal supplied from the pause determination unit 75 exceeds the threshold value dT _MAX . However, when the suspension history update unit 72 counts up the count value of the suspension history storage unit 71, the estimated temperature indicated by the signal supplied thereafter from the suspension determination unit 75 falls below the threshold value dT _OFF , that is, the motor 14 , 22 is stopped until the count value in the pause history storage unit 71 is counted up.

As shown in FIG. 4, when the count value reaching the threshold value dT _MAX exceeds a preset number, the second threshold value decreases. Therefore, when the second threshold value decreases, the pause rate of the motors 14 and 22 increases, and the temperature rise in the motors 14 and 22 becomes gradual as shown in FIG.

<Computers linked with printer control unit>
FIG. 8 is a diagram illustrating a schematic configuration of a computer 80 connected to the printer 10. The computer 80 is communicably connected to the inkjet printer 10 and outputs a print job including print data to the inkjet printer 10. The computer 80 is installed with a printer driver 82 for realizing a function of converting image data output from an application program (not shown) into print data in a format that can be interpreted by the inkjet printer 10. The image data has pixel data that is data relating to pixels of an image to be printed. This pixel data is processed in accordance with each processing stage described later, and finally converted into print data that is data relating to the color and size of dots formed on the paper P. The pixel data is data representing gradation values in multiple levels (for example, 256 levels from 0 to 255). Hereinafter, pixel data having RGB gradation values is referred to as RGB pixel data, and image data composed of RGB pixel data is referred to as RGB image data.

  Upon receiving image data output from an application program (not shown), the printer driver 82 generates print data by sequentially performing resolution conversion processing, color conversion processing, halftone processing, and rasterization processing on the image data.

  In the resolution conversion process, the resolution of the RGB image data is converted to a resolution (printing resolution) when an image is printed on the paper P. In this embodiment, since the print resolution is 360 × 360 dpi, the RGB image data is converted into RGB image data having a resolution of 360 × 360 dpi. For example, when the resolution of the RGB image data is lower than the printing resolution, the RGB pixel data is newly generated by interpolating (here, copying) between adjacent RGB pixel data of the original RGB pixel data, thereby achieving high resolution. Convert to RGB image data. On the other hand, when the resolution of the RGB image data is higher than the printing resolution, the RGB pixel data is thinned out at a constant rate to be converted into low-resolution RGB image data. Thus, in the resolution conversion process, interpolation and thinning of RGB pixel data are performed as appropriate.

  In the color conversion process, each RGB pixel data of the RGB image data is converted into data having gradation values in multiple levels (for example, 256 levels from 0 to 255) represented by the CMYK color space. Pixel data having CMYK gradation values is referred to as CMYK pixel data, and image data composed of CMYK pixel data is referred to as CMYK image data. This color conversion processing is performed by referring to a color conversion lookup table (not shown) that associates RGB gradation values with CMYK gradation values.

  In the halftone process, CMYK pixel data having multi-stage gradation values is converted into CMYK pixel data having small-stage gradation values that can be expressed by the inkjet printer 10. In the present embodiment, CMYK pixel data indicating 256 gradation values is converted to 2-bit CMYK pixel data indicating 4 gradation values. This 2-bit CMYK pixel data is set for each color. “00” indicates no dot formation, “01” indicates a small dot formation, “10” indicates a medium dot formation, and “11” indicates a large dot formation. . Note that large, medium, and small dots can be created separately by adjusting the waveform of the drive pulse to the piezoelectric element provided corresponding to each nozzle of the line head 22. In this embodiment, it is assumed that the dither method is used for halftone processing.

  In the rasterizing process, the CMYK image data subjected to the halftone process is changed in the order of data to be transferred to the inkjet printer 10. The data subjected to the rasterizing process is output to the inkjet printer 10 as print data.

Note that the printer 10 or the computer 80 is provided with an image data analysis unit 100 (present on the printer 10 side in FIG. 8). The image data analysis unit 100 is a part that determines whether the CR motor 14 or the PF motor 22 reaches a threshold value dT _MAX as shown in FIGS. 6 and 7 in a preliminary stage of executing printing based on the image data. . The details of the function of the image data analysis unit 100 will be described later.

<Regarding the processing executed by the pause history update unit>
FIG. 5 is a flowchart showing processing executed by the suspension history update unit 72. The pause history update unit 72 is supplied with a signal indicating the estimated temperature provided for comparison with the threshold value by the pause determination unit 75 every predetermined time (for example, one minute). While the flowchart of FIG. 5 is being executed, the suspension history update unit 72 has a storage area for storing the mask flag. The mask flag is a flag indicating that after the estimated temperature exceeds the threshold value dT _MAX , a state where the estimated temperature does not fall below the threshold value dT _OFF continues. In the following description, the variable (t) indicates the order of the estimated temperature indicated by the series of signals supplied to the pause history update unit 72.

  When a new signal indicating the estimated temperature (t) is supplied from the pause determination unit 75 (S100), the pause history update unit 72 determines whether the mask flag in the mask flag storage area is off (S110).

In step S110, when the mask flag of the mask flag area is determined to be turned off (S110: Yes), resting history update unit 72, the estimated temperature (t) to determine whether higher than the threshold value dT _MAX (S120 ).

When it is determined in step S120 that the estimated temperature (t) exceeds the threshold value dT _MAX (S120: Yes), the pause history update unit 72 increments the count value of the pause history storage unit 71 by one (S130). . Next, the pause history update unit 72 turns on the mask flag in the mask flag area (S140), returns to step S100, and waits for the supply of a signal indicating the next estimated temperature (t + 1).

When it is determined in step S110 that the mask flag in the mask flag region is on (S110: Yes), the pause history update unit 72 determines whether the estimated temperature (t) is below the threshold value dT _OFF (S150). ).

When it is determined in step S150 that the estimated temperature (t) is lower than the threshold value dT _OFF (S150: Yes), the pause history update unit 72 turns off the mask flag in the mask flag area (S160), and then proceeds to step S100. The process returns to step S3 and waits for supply of a signal indicating the next estimated temperature (t + 1).

When the above processing is repeatedly performed, even if the pause temperature indicated by the signal supplied from the pause determination unit 75 continuously exceeds the threshold value dT _MAX without falling below the threshold value dT _OFF , the number of count-ups during that time is 1 It can be suppressed to one. That is, while the rest determining unit 75 that the temperature is saturated over the inaction control the motor 14 and 22, the estimated temperature is moved up and down across the threshold dT _MAX is counted up resting history storage unit 71, Limited to the first one.

This principle will be described with reference to FIG. When the amount of heat accumulated in their motor 14 and 22 by the rotation of the CR motor 14 and the PF motor 22 is increased, the estimated temperature gradually increases toward the threshold dT _MAX. When the estimated temperature exceeds the threshold value dT _MAX , pause control is performed to delay the rotation of the next motors 14 and 22 by an amount corresponding to the pause time, and heat dissipation of the motors 14 and 22 is promoted. However, the dwell time, since only the length of the estimated temperature sufficient to slightly below the threshold dT _MAX not ensured, shortly motor 14 and 22 when the estimated temperature is below the threshold dT _MAX is rotated, the estimated temperature threshold It grows again towards dT _MAX . As a result, while the image recording is not completed and the motors 14 and 22 are forced to continuously rotate, the heat storage amount of the motors 14 and 22 is saturated at a position slightly lower than the limit value, and the threshold value dT _MAX is reached. Up and down movement of the estimated temperature is repeated. In contrast, according to the flowchart of FIG. 5, a further counting-up until after the count value is counted up when the estimated temperature of those vertical movement exceeds the threshold value dT _MAX First, the estimated temperature is below the threshold value dT _OFF Is not made. When sufficient rest is given to the CR motor 14 and the PF motor 22 and the estimated temperature falls below the threshold value dT _OFF , the count-up restriction is released, and when the estimated temperature is again higher than the threshold value dT _MAX , Count up.

  In the printer 10 according to the present embodiment, when the number of pause control that has been executed for the motors 14 and 22 is stored as a count value in the pause history storage unit 71 and the count value exceeds a preset number, the estimated temperature and The magnitude of the threshold value used for the comparison becomes smaller, and the pause time when the threshold value is exceeded becomes smaller. Therefore, when the motors 14 and 22 are overheated by using the printer 10 for a long period of time, the pause time is shortened instead of the pause limit being entered earlier. Thereby, it is possible to prevent the motors 14 and 22 from being damaged without giving the user an impression that a malfunction or failure has occurred.

Further, when the printer 10 according to the present embodiment increments the count value of the pause history storage unit 71 by one, until the estimated temperature indicated by the signal supplied thereafter from the pause determination unit 75 falls below the threshold value dT _OFF . The count up of the count value in the pause history storage unit 71 is stopped. Therefore, even when the heat storage amount of the motors 14 and 22 is saturated, useless count-up due to the estimated temperature moving up and down across the threshold value dT _MAX is prevented. Thereby, how to use the printer 10 estimated from the genuine count value stored in the suspension history storage unit 71 can be utilized for later model development.

<Other printing embodiments>
In the above embodiment, the count value stored in the pause history storage unit 71 is incremented regardless of the print mode of the printer 10. On the other hand, the count value for each print mode of the printer 10 may be individually stored in the pause history storage unit 71, and the pause history update unit 72 may count up the count value for each mode.

  That is, for example, it is assumed that there are two types of printing modes: a mode for printing plain paper (plain paper printing mode) and a mode for printing dedicated paper (dedicated paper printing mode). In this case, the count value of the pause history update unit 72 is incremented in each of the plain paper print mode and the dedicated paper print mode. This has the following advantages.

  The plain paper printing mode has a higher printing speed than the dedicated paper printing mode. Therefore, the driving amount (heat generation amount) of the PF motor 22 per unit time is larger than that of the dedicated paper printing mode. For this reason, when the plain paper printing mode is mainly used, the number of times the second threshold value (heat generation limit) as shown in FIG. For this reason, the count value in the pause history storage unit 71 exceeds a preset number (see FIG. 10, for example, 256) despite the state in which the dedicated paper printing mode is hardly used, and the second threshold value (heat generation limit) ) Will gradually become smaller.

  That is, when the plain paper printing mode is mainly used, when the dedicated paper printing mode is used, the second threshold value is lowered due to the influence of the count up in the plain paper printing mode (in FIG. "Paper printing mode + dedicated paper printing mode" is supported). Even when the dedicated paper printing mode is used, if the threshold value is used, the heat generation limit is reached quickly, so that the printing throughput is unnecessarily reduced.

  On the other hand, as shown in FIG. 10, when the count value in the pause history storage unit 71 is divided separately for the plain paper print mode and the dedicated paper print mode, the count in the plain paper print mode is used in the dedicated paper print mode. Not affected by up. Therefore, the printing throughput in the dedicated paper printing mode is not reduced unnecessarily. In addition, in dedicated paper printing, the user is not given the impression that the printing throughput has been reduced, so that it is not necessary to give the user the impression that the performance of the printer 10 has deteriorated.

  As for the PF motor 22, the plain paper printing mode reaches the second threshold value (heat generation limit) earlier than the dedicated paper printing mode, but for the CR motor 14, the plain paper printing mode is more suitable for plain paper printing. The threshold (heat generation limit) is reached earlier than in the mode. Therefore, regarding the CR motor 14, the count value in the suspension history storage unit 71 may be divided separately for the plain paper print mode and the dedicated paper print mode.

  Note that the printing mode is not limited to the plain paper printing mode and the dedicated paper printing mode, and may be counted individually in various other printing modes.

  The above is true not only for the printing mode such as the plain paper printing mode / dedicated paper printing mode but also for the image data. For example, when the image data analysis unit 100 (see FIG. 8) determines that the image data corresponds to printing in the plain paper printing mode, and the image data corresponds to printing in the dedicated paper printing mode. The count value in the pause history storage unit 71 may be divided separately depending on when it is determined that.

  Further, the analysis by the image data analysis unit 100 is a case where it is determined in advance that the CR motor 14 is printed based on specific image data that is hardly driven. When sheets are executed, the suspension history storage unit 71 may count up exclusively so that printing based on other image data is not affected. In this way, the print throughput is not reduced unnecessarily due to the influence of the specific image data.

Note that the count value in the pause history storage unit 71 may be returned to the initial value when a predetermined condition is satisfied. As the predetermined condition, for example, a case where the state of not reaching the threshold value dT _MAX shown in FIG.

<Other embodiments>
The present invention can be modified in various ways.

In the above embodiment, when the estimated temperature falls below the threshold, the count-up restriction by the pause history update unit 72 is released. On the other hand, as shown in FIG. 7, in addition to when the estimated temperature falls below the threshold value dT _OFF , the restriction may be released when the printer is turned on and then turned on again.

  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.

In the above embodiment, the estimated temperature of the motors 14 and 22 is obtained based on the effective current value I _EFF obtained from the actual speed of the motors 14 and 22 and the duty ratio thereof, and the pause control is performed based on the magnitude relationship between the estimated temperature and the threshold value. Judgment was necessary. On the other hand, whether or not the stop control is necessary may be determined based on the magnitude relationship between the effective current value I _EFF itself obtained from the actual speed of the motors 14 and 22 and the duty ratio thereof and the threshold value. In short, whether or not to pause is determined based on the magnitude relationship between a certain value correlated with the amount of heat accumulated in the motors 14 and 22 (corresponding to a “heat amount correlation value”) and a threshold set according to the attribute. It only has to be.

  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.

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 relationship between the threshold value used for a comparison with an effective current value, and rest time. It is a flowchart which shows the process which a dormant history update part performs. It is a figure which shows the change of the effective current value of a motor. It is a figure for demonstrating a modification. It is a figure which shows schematic structure of a computer and a printer. It is a diagram showing a relationship between the threshold dT _MAX and the second threshold value. It is a figure which shows the relationship between each printing mode and a count value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Driving pulley (equivalent to "driven body"), 12 ... Driven pulley (equivalent to "driven body"), 13 ... Belt (equivalent to "driven body"), 14 ... CR motor, 15 ... Linear scale , 16 ... guide shaft, 17 ... carriage (corresponding to "driven body"), 18 ... ink cartridge, 19 ... recording head, 20 ... linear encoder, 21 ... driving roller (corresponding to "driven body"), 22 ... PF motor, 23 ... rotary scale, 24 ... rotary encoder, 25 ... left side wall, 26 ... right side wall, 27 ... rear side wall, 30 ... control unit (corresponding to "control means", "calculation means"), 31 ... first Motor driver 33 ... second motor driver 35 ... interface circuit 36 ... recording head control circuit 37 ... CPU 38 ... RAM 39 ... ROM 40 ... EEPROM 50 ... DC unit DESCRIPTION OF SYMBOLS 51 ... Position calculating part 52 ... Speed calculating part 53 ... Position deviation calculating part 54 ... Target speed specific | specification part 55 ... Speed deviation calculating part 56 ... Proportional element 57 ... Integration element 58 ... Differentiation element 62 ... Control value addition unit, 63 ... PWM signal output unit, 64, 65 ... selector, 70 ... pause control unit (corresponding to "counting means", "threshold specifying means", "determination means", "rotation control means"), 71 ... Pause history storage unit, 72 ... Pause history update unit, 73 ... Pause time table, 74 ... Current value calculation unit, 75 ... Pause determination unit, 76 ... Table specifying unit, 77 ... Delay unit, 90 ... Target speed table

Claims (8)

A driven body;
A motor that applies driving force to the driven body through its own rotation;
A calculating means for calculating a heat quantity correlation value that is a value correlated with the heat quantity accumulated in the motor;
A means for intermittently rotating the motor at predetermined intervals, and a control means for shortening the length of the interval as the number of times the calculated calorie correlation value exceeds the first threshold increases;
A printer comprising:   2. The printer according to claim 1, wherein the first threshold value is individually counted at least for each print mode or for each image data. A table in which a second threshold value used for comparison with the calorie correlation value is associated with time data indicating an interval time, and a table associated with time data indicating a longer time as a larger second threshold value is stored. Memory,
Further comprising
The control means includes
Counting means for counting up the number of times that the calculated heat quantity correlation value exceeds the first threshold;
Until the number counted up by the counting means reaches a preset number, the largest second threshold value is specified from the second threshold values in the table, and the counted number is set to the set number. After reaching the threshold value specifying means for specifying a second threshold value smaller than the largest second threshold value from among the second threshold values of the table,
Determining means for determining whether the calculated heat quantity correlation value exceeds the second threshold specified by the threshold specifying means;
When the determination means determines that the heat quantity correlation value exceeds the second threshold value, the time data stored in the table in association with the second threshold value specified by the threshold value specifying means is specified, and the time data Rotation control means for rotating the motor with a time interval indicated by
The printer according to claim 1, further comprising: The counting means includes
When the number of times that the calculated heat quantity correlation value exceeds the first threshold value is counted up, the calculation means further counts until a heat quantity correlation value that is lower than another third threshold value that is smaller than the first threshold value is calculated. Stop up,
The printer according to claim 2. A calculation step for calculating a heat quantity correlation value that is a value correlated with the heat quantity accumulated in the motor that gives a driving force to the driven body through its own rotation;
A control step of intermittently rotating the motor with a predetermined interval, and shortening the length of the interval as the number of times the calculated heat quantity correlation value exceeds the first threshold increases;
A printer motor control method comprising: A driven body;
A motor that applies driving force to the driven body through its own rotation;
First threshold value setting means for setting a first threshold value that has a correlation with the amount of heat accumulated in the motor and that stops driving the motor;
Counting means for counting the number of times to reach the first threshold;
A second calculating means for calculating a second threshold value that has a correlation with the amount of heat accumulated in the motor and that starts the heat generation limitation of the motor;
Threshold value specifying means for specifying to decrease the second threshold value as the count value of the first threshold value in the counting means increases;
A printer comprising:   The printer according to claim 6, wherein the first threshold is individually counted at least for each print mode or for each image data.   8. The printer according to claim 6, wherein the first threshold value is set to an initial value when a predetermined condition is satisfied.

Images