JP2010213424A - Motor control device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration of control performance due to dirt by specifying a section where dirt is attached to a linear scale and performing compensation control in the section.
When an abnormal speed of a carriage is detected due to dirt 71 and 72 of a linear scale 46, the carriage is driven in the entire scanning area to measure the total count value M at the time of abnormality, and the carriage is further connected to one end of the scanning area. The first count value ka from the start of driving until the abnormal speed is detected, and the second count value kb from the other end side until the abnormal speed is detected are measured. To do. Then, the sum of ka and kb is calculated by subtracting the sum of ka and kb from the nominal count value N in the entire scanning area, and the sum of ka and kb is subtracted from the total count value M at the time of abnormality to obtain the actual count value z in the dirt section. Is calculated to identify the dirt section. This dirt section is used as a compensation section, and thereafter, compensation control using the holding operation amount is performed in this compensation section.
[Selection] Figure 5

Description

  The present invention relates to a motor control device that controls driving of a driven body driven by a motor based on a signal from a linear encoder, and an image forming apparatus equipped with the motor control device.

  Conventionally, in an ink jet printer, driving of a carriage on which a recording head is mounted is controlled by a motor. In order to control the carriage drive by the motor with high accuracy, it is necessary to detect the driving state such as the position and speed of the carriage. In general, linearity in which slits are formed at predetermined intervals is used for detecting the driving state. A linear encoder having a scale is used.

  In a motor control device using a linear encoder, a pulse signal (encoder signal) output from the linear encoder is counted each time the carriage moves by a certain amount (slit interval), and the position and speed of the carriage are based on the count value. Is detected. Then, feedback control is performed so that the detected position and speed coincide with the target position / target speed. The encoder signal is generally counted based on, for example, its rising edge, falling edge, or both.

  By the way, the linear scale constituting the linear encoder may become contaminated due to ink adhering to the production line of the ink jet printer or grease inside the apparatus adhering when used by the user.

  If dirt is attached to the linear scale, the motor control device may count the number of encoder signals less (or more) than actual due to the dirt, and the carriage speed may be erroneously detected. .

  Therefore, for example, when the carriage is driven at a constant speed, if the detection speed fluctuates due to the contamination of the linear scale, the detected fluctuating speed fluctuates even though it does not actually fluctuate. On the basis of this, unnecessary control for suppressing the speed fluctuation is performed.

  For example, Japanese Patent Application Laid-Open No. H10-260260 discloses a technique for dealing with such encoder scale contamination, in an image forming apparatus in which a carriage is moved by a motor, when the detected speed of the carriage is an abnormal speed value other than a predetermined threshold value. When the abnormal value appearance section is in a very small range (for example, one section of the control cycle), the drive control of the motor is performed using the immediately preceding detection speed instead of the detection speed, and a continuous control cycle (for example, four or more control cycles). If an abnormal speed value is detected in step (1), or if an abnormal speed value is detected continuously several times at the same location, it is determined that the encoder is dirty and a notification to the user is made.

  Further, in Patent Document 2, in a laser printer in which an encoder scale is provided on a belt such as a conveyance belt or an intermediate transfer belt, the calculation speed is set to a predetermined regularity due to the joint of the scale or the influence of toner attached to the scale. It is described that, when it is determined that the value is out of the range, an average value of a target speed or a past calculation speed is used as a feedback amount, and an operation amount is calculated based on this.

JP 2006-213042 A JP 2006-178374 A

  However, although the technique described in Patent Document 1 can determine the presence / absence of encoder contamination based on the generation section and frequency of abnormal speed values, when encoder contamination is determined, it simply notifies the user and performs maintenance, etc. No specific control method has been proposed for eliminating the influence of encoder contamination in a section where encoder contamination has occurred.

  In both Patent Documents 1 and 2, it is not possible to accurately detect the section where the encoder scale is contaminated, and this is detected with respect to the abnormal detection speed caused by the encoder scale dirt. Control for compensation is performed more than necessary, and control performance may be deteriorated.

  In addition, in order to eliminate the influence of dirt on the encoder scale, when a speed abnormality is detected, the motor control is performed using the immediately preceding detected speed, target speed, etc. as a feedback amount. There is a possibility that control in consideration of the dynamic load is not performed and the control accuracy is deteriorated.

  The present invention has been made in view of the above problems, and a motor configured to detect a driving state of a driven body by a linear encoder and to control driving of the driven body by a motor based on the detected driving state. In the control device, in the entire drive range of the driven body, the section where the linear scale is contaminated is specified, and appropriate compensation corresponding to the section is used without using the actual detection result in the section. The purpose is to suppress the deterioration of the control performance due to the contamination of the linear scale.

  The invention according to claim 1, which has been made to solve the above-mentioned problems, includes a linear encoder that outputs a pulse-like encoder signal in accordance with the amount of movement of a driven body driven by a motor on a preset movement path. A drive state detection unit that counts encoder signals from the linear encoder and detects the speed and position of the driven body based on the count value; and a detection speed by the drive state detection unit at every predetermined calculation timing. An operation amount calculation means for calculating an operation amount for controlling the motor and outputting the operation amount to the motor, comprising: an abnormal speed detection means; a compensation section detection means; and an operation amount compensation means And.

The abnormal speed detecting means detects whether or not the speed detected by the drive state detecting means is an abnormal speed that is out of a preset normal speed range.
When the abnormal speed is detected by the abnormal speed detecting means, the compensation section detecting means drives the driven body from one end of the movement path and counts an encoder signal until the abnormal speed is detected by the abnormal speed detecting means. Thus, the first count value ka is measured, and the second count value kb is measured by driving the driven body from the other end of the movement path and counting the encoder signal until the abnormal speed is detected by the abnormal speed detecting means. Is measured, and a position between the positions corresponding to the respective count values ka and kb is detected as a compensation section.

  The manipulated variable compensation means determines whether the driven body has entered the compensation section based on the detection position by the driving state detection means when driving the driven body after the compensation section is detected by the compensation section detection means. When determining and entering the compensation section, a holding operation obtained based on one or a plurality of operation amounts calculated by the operation amount calculation means before entering the compensation section as the operation amount within the compensation section Output quantity.

  In a linear encoder, for example, if dirt is attached to the linear scale constituting the linear encoder, even if the driven body is moving at a constant speed on the movement path, it corresponds to the position where the dirt is attached. When passing through the position, the detection speed in the drive state detection means may vary due to the influence of dirt or the like.

  Therefore, in the first aspect of the invention, when an abnormal speed is detected, the abnormal speed is caused by dirt or the like of the linear scale (that is, dirt or the like is attached to the linear scale). Based on a temporary assumption, a section where the dirt is attached is specified as a compensation section. Then, when driving the driven body thereafter, in the compensation section, instead of the operation amount calculated by the operation amount calculation means (the operation amount calculated based on the detection speed by the drive state detection means), the operation amount The motor is controlled by the holding operation amount from the amount compensation means.

  Therefore, according to the motor control device of the first aspect, in the section (compensation section) where dirt or the like is attached, the influence of the variation in the detection speed caused by the dirt or the like is reflected in the motor control. Can be prevented, and the driven body can be driven stably. In addition, the motor control based on the holding operation amount is performed only within the compensation section, and the operation amount calculated based on the detection speed is used in the other sections as usual. The motor can be controlled with high accuracy.

  The holding operation amount used in the compensation section is a value that takes into account the sliding load of the driven body, which is actually calculated by the operation amount calculation means before the driven body enters the compensation section. Therefore, by using such a holding operation amount in the compensation section, more appropriate control can be realized even in the compensation section.

  Next, according to a second aspect of the present invention, in the motor control device according to the first aspect, when the abnormal speed is detected by the abnormal speed detecting means, the driven body is moved from one end of the moving path to the other end. An abnormal total count value measuring means for measuring the abnormal total count value M by driving the entire area and counting the encoder signals being driven, and the sum of the first count value ka and the second count value kb is abnormal Compensation interval actual count value calculating means for calculating the compensation interval actual count value z by subtracting from the entire time count value M is provided. Then, when the driven body enters the compensation section, the manipulated variable compensation means detects the end position of the compensation section based on the count value and the actual count value z within the compensation section after the entry of the driven state detection means. The holding operation amount is output until the end position is detected.

  That is, by subtracting the sum of the first count value ka and the second count value kb from the total count value M at the time of abnormality, a value that can be actually counted in the compensation section where the contamination or the like occurs (the actual count value z in the compensation section). ) Is obtained.

  Therefore, after the driven body enters the compensation section, the end position of the compensation section can be detected based on the actual count value z in the compensation section. For example, in the case of z = 2, after entering the compensation section, it is still a compensation section until 2 counts are measured, and when the third count is measured, it can be determined that the exit is from the compensation section.

  Therefore, according to the motor control device of the second aspect, it is possible to accurately detect the timing at which the compensation section ends after the driven body enters the compensation section. Therefore, the motor control by the holding operation amount can be performed sufficiently and sufficiently, and the deterioration of the control performance can be more reliably suppressed.

  Next, in the third aspect of the invention, in the motor control device of the second aspect, when the linear encoder is normal, the driven body is driven in the entire region from one end to the other end of the moving path. Storage means in which a nominal count value N, which is a count value of the encoder signal being driven, is stored in advance, and when an abnormal speed is detected by the abnormal speed detection means, the all-time count value measurement means always before By subtracting the abnormal total count value M measured by the above from the nominal count value N, the abnormal count error detecting means for detecting the abnormal count error n and the compensation section detecting means after detecting the compensation section When driving the driven body, when the driven body goes out of the compensation section, the count value being counted by the drive state detecting means is changed to the count value when the driven body goes out of the compensation section It comprises a correction means for correcting a value obtained by adding the abnormal count difference n, the.

  That is, the number of encoder signals counted while the driven body is moving in the compensation section is counted if the compensation section is in a normal state in which there is no dirt due to the influence of dirt, etc. It becomes a value different from the count number that should be done.

  Therefore, the abnormal count error n is detected by subtracting the abnormal total count value M from the nominal count value N. This abnormal count error n means the difference between the actual count value affected by dirt and the like and the normal count value that should be counted if there is no dirt in the compensation interval. is there. When the driven body goes out of the compensation section, the count value is corrected to a correct value corresponding to the position of the driven body at that time by adding the abnormal count error n to the actual count value at that time. .

  Therefore, according to the motor control device of the third aspect, the deviation between the actual position of the driven body after passing through the compensation section and the count value can be eliminated, and the motor control after passing through the compensation section is performed. This can be performed with higher accuracy without being affected by the compensation interval (that is, the influence of dirt or the like).

Next, according to a fourth aspect of the present invention, in the motor control device according to the third aspect, the operation amount compensation means outputs the holding operation amount when the abnormality count error n is not zero.
The reason why the abnormal speed is detected is not necessarily limited to that caused by the encoder, such as contamination of the linear scale, and the speed may actually fluctuate due to, for example, load fluctuation. Therefore, when an abnormal speed is detected, it is determined whether or not the cause of the abnormal speed is due to the encoder by checking whether the abnormal count error n is 0 or not. Then, when the abnormal count error n is not 0, that is, when it is determined that the cause of the abnormal speed is caused by the encoder, the control with the holding operation amount in the compensation section is performed.

Therefore, according to the motor control device of the fourth aspect, it is possible to more accurately determine whether or not compensation control is necessary, and it is possible to provide a motor control device with higher performance.
According to a fifth aspect of the present invention, in the motor control device according to the fourth aspect, when the abnormal count error n is detected as 0 by the abnormal count error detecting means, a predetermined determination is made based on the detection result. First notification means for performing the notified notification is provided.

  If the abnormal count error n is 0, that is, if the abnormal total count value M and the nominal count value N coincide with each other, it can be determined that the linear encoder is not contaminated and is in a normal state. For this reason, the fact that the abnormal speed is detected even though the count error n at the time of abnormality is 0 may mean that some abnormality different from the contamination of the linear encoder has occurred. Therefore, if the abnormal time count error n is 0 when the abnormal speed is detected, the first notification means performs notification.

  Therefore, according to the motor control device of the fifth aspect, since the notification is performed when the cause of the abnormal speed is not due to the contamination of the linear encoder, the user of the motor control device Based on the notification, it is possible to take appropriate measures against the occurrence of an abnormality.

  Next, according to a sixth aspect of the present invention, in the motor control apparatus according to any one of the third to fifth aspects, the sum of the first count value ka and the second count value kb is calculated as a nominal count value N. The compensation interval width calculating means for calculating the compensation interval width m, which is the count value that should be counted by the driving state detecting means in the compensation interval, and the compensation interval width detected by the compensation interval width calculating means compensation interval width determining means for determining whether m is larger than a preset compensation interval width threshold value. The operation amount compensation means outputs the holding operation amount when the compensation section width determination means determines that the compensation section width m is equal to or less than the compensation section width threshold.

  Although the holding operation amount is a value obtained based on the actual operation amount before entering the compensation section, the actual position and speed of the driven body moving in the compensation section are directly reflected. Not a value. For this reason, when the compensation interval width m is too wide, it is not preferable to perform the control with the holding operation amount over the wide compensation interval.

  Therefore, as in the invention described in claim 6, the control by the holding operation amount is limited to the case where the compensation interval width m is equal to or less than the compensation interval width threshold, thereby preventing the deterioration of the control performance. Can do.

  As a case where the compensation interval width m is wide, a case where a single dirt is continuously adhered over a wide range, a case where dirt in a narrow region is intermittently scattered, and the like are assumed. Is done.

  Next, in the seventh aspect of the present invention, in the motor control device according to the sixth aspect, when the compensation section width determining unit determines that the compensation section width m is larger than the compensation section width threshold, the determination result is obtained. Second notification means for performing predetermined notification based thereon is provided.

As described above, when the compensation interval width m is too wide, it is not preferable to perform the control with the holding operation amount over the entire wide compensation interval.
Therefore, as in the seventh aspect of the invention, if the notification is performed when the compensation interval width m is too wide (larger than the compensation interval width threshold), the user of the motor control device or the like can notify the notification. Based on this, it is possible to take appropriate measures against abnormal occurrence.

  Next, according to an eighth aspect of the present invention, in the motor control device according to any one of the first to seventh aspects, the driven body is driven after the compensation section is detected by the compensation section detecting means. In this case, when the abnormal speed is detected by the abnormal speed detection means before the driven body enters the compensation section, the start position of the compensation section is set by a predetermined amount before the currently detected position. Updating means for updating to a position is provided.

  The start position of the compensation section (based on the count values ka and kb) detected by the compensation section detection means is based on the count value when the abnormal speed is detected. It does not always coincide with the end of the position. In other words, depending on the relationship between the detection timing of the abnormal speed and the count timing of the encoder signal, the abnormal speed may be detected after a certain time has passed (moved) after entering the area where dirt or the like is attached. In this case, the entire area where dirt or the like is actually attached is not completely set as a compensation section, and there is a possibility that the detection speed fluctuates due to encoder dirt or the like before entering the compensation section.

  Therefore, in the invention described in claim 8, when the compensation section is detected and the control based on the holding operation amount is performed in the section, if the abnormal speed is detected, the start position of the compensation section is set. I try to make it faster.

  As a result, even if there is a deviation or error between the start position of the set compensation section and the actual dirt start position, it can be corrected. Thus, the control based on the holding operation amount can be surely performed.

  Here, specifically, the holding operation amount output by the operation amount compensation unit is calculated by the operation amount calculation unit at a calculation timing immediately before the driven body enters the compensation section, for example, as described in claim 9. For example, as described in claim 10, the operation amount may be an average value of each operation amount calculated by the operation amount calculation means at a plurality of calculation timings before the driven body enters the compensation section. .

  According to the motor control device of the ninth aspect, by using the actual operation amount calculated immediately before entering the compensation section, the compensation control is performed with a more appropriate operation amount considering the sliding load at the point. Since this can be performed, a more appropriate driving force can be applied to the driven body even within the compensation section.

  However, the operation amount calculated by the operation amount calculation means may vary due to the influence of torque variation or noise due to cogging generated as the motor rotates. Therefore, when (one) operation amount immediately before entering the compensation section is set as the holding operation amount as in claim 9, how much the one operation amount is affected by the torque fluctuation of the motor, noise, etc. In some cases, it is not always appropriate to set the operation amount as the holding operation amount.

  Therefore, as described in claim 10, if an average value of a plurality of operation amounts calculated before entering the compensation section is used as a holding operation amount, a more appropriate operation amount in which influences such as torque fluctuation and noise are reduced. Compensation control can be performed at. Accordingly, a more appropriate driving force can be applied to the driven body within the compensation section.

  Next, an invention according to an eleventh aspect is the motor control device according to any one of the first to tenth aspects, a recording head that forms an image on a recording medium by ejecting ink, An image forming apparatus comprising: a carriage on which a recording head as a driven body is mounted.

  According to the image forming apparatus configured as described above, even if dirt or the like adheres to the encoder, the influence can be suppressed and the carriage can be controlled with high accuracy, and a high-quality image can be formed.

1 is a block diagram illustrating an electrical configuration of an inkjet printer according to an embodiment. It is explanatory drawing showing schematic structure of the image formation mechanism in the inkjet printer of embodiment. It is explanatory drawing showing the specific structure of CR linear encoder, (a) represents the structure of a linear scale, (b) is a figure showing the relative positional relationship with the structure of a detection part, and a linear scale. It is explanatory drawing for demonstrating that detection speed fluctuates by the influence of the dirt adhering to a linear scale. It is explanatory drawing for demonstrating the detection of the contamination area in a linear scale, and the compensation control based on the detection result. It is a flowchart showing the carriage drive process performed by ASIC.

Preferred embodiments of the present invention will be described below with reference to the drawings.
(1) Configuration of Inkjet Printer FIG. 1 shows an electrical configuration of an inkjet printer 1 according to an embodiment to which the present invention is applied.

  The ink jet printer 1 of this embodiment forms an image on the paper P while separating and transporting the paper P (not shown in FIG. 1; see FIG. 2) contained in a paper tray one by one. As shown in FIG. 1, a recording head 11 in which a plurality of nozzles for ejecting ink droplets onto the paper P are arranged, a carriage 12 on which the recording head 11 is mounted, and the paper P by the recording head 11. A carriage (CR) motor 13 that is a drive source for reciprocatingly driving the carriage 12 in the main scanning direction (a direction perpendicular to the sub-scanning direction in which the paper P is conveyed) and the amount of movement of the carriage 12 A CR linear encoder 14 for detecting (position, speed, moving direction, etc.) and a line feed (LF) that is a driving source of a conveying roller (not shown) that conveys the paper P in the sub-scanning direction. And over motor 21, and a, and LF rotary encoder 22 for detecting the rotation amount of the LF motor 21 (and thus the transport amount of the paper P).

  Note that the CR motor 13 and the LF motor 21 are both DC motors in this embodiment. Further, the CR linear encoder 14 and the LF rotary encoder 22 are both incremental optical encoders in the present embodiment.

  The ink jet printer 1 also includes a recording head driver 15 for driving the recording head 11 to eject ink droplets, a CR motor driver 16 for driving the CR motor 13, and an LF motor 21. And an ASIC 2 for controlling these operations by outputting a drive command to each of the drivers 15, 16, and 23.

  Here, a specific configuration of the image forming mechanism including the carriage 12, the CR motor 13, the CR linear encoder 14 and the like in the inkjet printer 1 will be described with reference to FIG. FIG. 2 is an explanatory diagram illustrating a schematic configuration of an image forming mechanism in the inkjet printer 1 of the present embodiment.

  As shown in FIG. 2, in the image forming mechanism in the inkjet printer 1 of the present embodiment, the guide shaft 41 is installed in the width direction (main scanning direction) of the paper P, and the recording head 11 is mounted on the guide shaft 41. The carriage 12 is inserted.

  The carriage 12 is connected to an endless belt 42 provided along the guide shaft 41, and the endless belt 42 is installed on a driven pulley 44 installed on one end side of the guide shaft 41 and on the other end side of the guide shaft 41. It is latched between the driven pulley 43 of the CR motor 13. Accordingly, the carriage 12 is reciprocated in the main scanning direction along the guide shaft 41 by the driving force of the CR motor 13 transmitted through the endless belt 42.

  Further, in the vicinity of the guide shaft 41, a linear scale 46 having slits formed at predetermined intervals in the main scanning direction is installed along the guide shaft 41 (that is, along the movement path of the carriage 12). In addition, a detection unit 47 (see FIG. 3) in which the light emitting unit 50 and the light receiving unit 60 are arranged with the linear scale 46 interposed therebetween is provided at a position facing the linear scale 46 in the carriage 12. 46 constitutes a CR linear encoder 14.

  Here, a more specific configuration of the CR linear encoder 14 will be described with reference to FIG. As shown in FIG. 3A, the linear scale 46 constituting the CR linear encoder 14 has slits 48 formed at predetermined intervals.

  In addition, as shown in FIG. 3B, the detection unit 47 is arranged such that the light emitting unit 50 and the light receiving unit 60 are sandwiched between the linear scale 46. The light emitting unit 50 includes two light emitting elements (A phase light emitting element 51 and B phase light emitting element 52), and the light receiving unit 60 also includes two light receiving elements (A phase light receiving element 61 and B phase light receiving element 62). The light emitted from the A phase light emitting element 51 is received by the A phase light receiving element 61, and the light emitted from the B phase light emitting element 52 is received by the B phase light receiving element 62.

  Since the detection unit 47 moves in the main scanning direction with the movement of the carriage 12, the corresponding light emitting elements 51, 62 correspond to the light receiving elements 61, 62 depending on the relative positional relationship between the detection unit 47 and the linear scale 46. There are cases where the light from 52 is received and when it is not received. In the state shown in FIG. 3B, the light from the A-phase light emitting element 51 is blocked by the linear scale 46 and is not received by the A-phase light receiving element 61, but the light from the B-phase light emitting element 52 is slit 48. And the light is received by the B-phase light receiving element 62.

  With such a configuration, the detection unit 47 outputs two types of pulse signals (A-phase signal and B-phase signal) having a phase difference (90 degrees in the present embodiment) as the carriage 12 moves. One of them is an A phase signal corresponding to the light receiving state at the A phase light receiving element 61, and the other is a B phase signal corresponding to the light receiving state at the B phase light receiving element 62.

  The A phase signal is a pulse signal that is at a low level while the light from the A phase light emitting element 51 is received by the A phase light receiving element 61 and is at a high level when the light is not received. Similarly, the B-phase signal is a pulse signal that is at a low level while the light from the B-phase light emitting element 52 is received by the B-phase light receiving element 62 and is at a high level when the light is not received. However, the relationship between the light receiving state in each of the light receiving elements 61 and 62 and the high / low level of each phase signal is not limited to the above relationship, and is high when receiving light and low when blocking light. It may output a pulse signal.

  The pulse signals of the phases A and B are when the moving direction of the carriage 12 is the right direction in FIG. 2 (the direction from the driven pulley 44 side to the driving pulley 43 side, hereinafter also referred to as “forward direction”). The phase of the A phase signal is advanced 90 degrees with respect to the phase B signal. Conversely, in the case of the left direction in the figure (the direction from the drive pulley 43 side to the driven pulley 44 side, hereinafter also referred to as “reverse direction”), the phase of the A phase signal is delayed by 90 degrees with respect to the B phase signal. Has been. The A and B phase pulse signals are input to the CR linear encoder processing unit 34 in the ASIC 2.

  The CR linear encoder processing unit 34 determines the position, speed, moving direction, and the like of the carriage 12 (hereinafter collectively referred to as “driving state”) based on the A and B phase pulse signals input from the CR linear encoder 14. To detect. The detection result is output to the recording control unit 31 and the CR motor control unit 32.

  Among the detection of the driving state of the carriage 12 by the CR linear encoder processing unit 34, in particular, the detection of the position and speed of the carriage 12 is performed based on the A-phase signal in this embodiment.

  That is, the CR linear encoder processing unit 34 detects the rising edge and the falling edge of the A phase signal among the A and B phase pulse signals input from the CR linear encoder 14. Each time each edge is detected, the detected number is counted by a position counter (not shown).

  Therefore, the CR linear encoder processing unit 34 can detect where the carriage 12 is located on the movement path based on the count value (edge detection count value) of the position counter. In the following description, the term “encoder signal” simply means an A-phase signal. Further, “counting” the encoder signal means counting the rising edge and falling edge of the A-phase signal.

  In addition, the CR linear encoder processing unit 34 synchronizes with the detection timing of each edge of the A phase signal, and the physical resolution of the CR linear encoder 14 and the edge interval from when the previous edge is detected until the current edge is detected. The movement speed (detection speed) of the carriage 12 is detected by calculation based on time.

  Further, the CR linear encoder processing unit 34 includes a compensation control information setting unit 36. The compensation control information setting unit 36 determines whether dirt or the like is attached to the linear scale 46 constituting the CR linear encoder 14 based on the detected speed of the carriage 12. If it is determined that dirt or the like is attached, the attached section (dirt section) is specified, and dirt section information that is information related to the dirt section is transmitted to the CR motor control unit 32. . The specific calculation processing performed by the compensation control information setting unit 36 will be described in detail later.

  The recording control unit 31 generates a drive command for driving the recording head 11 based on the driving state of the carriage 12 detected by the CR linear encoder processing unit 34, and outputs it to the recording head driver 15. The recording head driver 15 ejects ink droplets by applying a driving voltage to the recording head 11 in accordance with a driving command input from the recording control unit 31.

  The CR motor control unit 32 generates an operation amount for controlling the CR motor 13 at every predetermined calculation timing based on the driving state of the carriage 12 detected by the CR linear encoder processing unit 34. Then, a drive command (such as a PWM signal) corresponding to the generated operation amount is output to the CR motor driver 16. That is, the CR motor control unit 32 performs feedback control of the carriage 12 based on the position, speed, movement direction, and the like of the carriage 12 detected by the CR linear encoder processing unit 34.

  However, in the present embodiment, when the compensation control information setting unit 36 detects that dirt or the like is attached to the linear scale 46 and the dirt control section information is transmitted from the compensation control information setting unit 36, the CR motor In the dirt section, the control unit 32 does not perform normal operation amount generation (feedback control) based on the detection speed, but performs compensation control using the holding operation amount calculated by a predetermined calculation method. This compensation control will also be described in detail later.

  The CR motor driver 16 is composed of, for example, an H-bridge circuit for supplying power to the CR motor 13 to rotate the CR motor 13, and the CR motor 13 according to a drive command input from the CR motor control unit 32. Electric power is supplied to the CR motor 13 to rotate.

  On the other hand, the LF rotary encoder 22 has slits formed at predetermined intervals along the circumference, and has an encoder wheel (not shown) that rotates with the rotation of the LF motor 21, according to the rotation of the LF motor 21 (that is, paper). Outputs two pulse signals (A phase signal and B phase signal) that are out of phase with each other (according to the conveyance of P), and these pulse signals are input to the LF rotary encoder processing unit 35 in the ASIC 2. The

  The LF rotary encoder processing unit 35 detects the position and speed of the paper P based on the A and B phase pulse signals input from the LF rotary encoder 22. The detection result is output to the LF motor control unit 33.

  The LF motor control unit 33 generates an operation amount for controlling the LF motor 21 based on the position and speed of the paper P detected by the LF rotary encoder processing unit 35. Then, a drive command (such as a PWM signal) corresponding to the generated operation amount is output to the LF motor driver 23.

  The LF motor driver 23 includes, for example, an H bridge circuit for supplying power to the LF motor 21 to rotate the LF motor 21, and the LF motor 21 is in accordance with a drive command input from the LF motor control unit 33. Electric power is supplied to the LF motor 21, and the LF motor 21 is rotated.

  In addition, the inkjet printer 1 is used as a work area when the CPU 3 that centrally controls each part of the inkjet printer 1 including the ASIC 2, the ROM 4 that stores programs executed by the CPU 3, and the CPU 3 executes the programs. The RAM 5 is connected to an EEPROM 6 in which various setting information and the like are stored, a personal computer (PC) (not shown), etc., and receives various data such as image formation commands and image data transmitted from the PC or the like, or the ink jet printer. 1 includes an interface (I / F) 7 for transmitting various data such as one operation state to a PC and the like, and an operation / display unit 8 including various operation buttons and a display device (not shown). These and the ASIC 2 are connected to each other via the bus 9.

  In the ink jet printer 1 configured as described above, when an image is formed on the paper P by the recording head 11, first, the carriage 12 stopped in the standby area (see FIG. 2) has a predetermined initial value in the adjustment area. Moved to position.

  Thereafter, when driving of the carriage 12 for image formation is started, the carriage 12 starts to accelerate from the initial position toward the recording area (that is, in the forward direction), and eventually reaches a predetermined target constant speed. In this embodiment, at least in the recording area, the target is moved at a constant speed.

  While the recording area is moved at a constant target speed, ink droplets are ejected from the recording head 11 onto the paper P, and image formation for one line on the paper P is performed. Thereafter, the carriage 12 decelerates and stops in the standby area. After stopping in the standby area, the carriage 12 starts moving again from the standby area toward the adjustment area (that is, in the reverse direction), and image formation for the next one line is performed in the recording area. Thereafter, the carriage 12 decelerates and again stops within the adjustment area.

  In this way, the carriage 12 is reciprocated in the main scanning direction, and image formation is performed line by line by the recording head 11 each time, whereby image formation for one page on the paper P is finally performed.

(2) Variation in detection speed due to contamination of linear scale In the inkjet printer 1 configured as described above, when contamination or the like adheres to the linear scale 46, the CR linear encoder processing unit 34 causes the encoder to be affected by the contamination. The signal (A phase signal) is counted less (or more) than actual.

  FIG. 4 shows an example in which dirt is adhered to the linear scale 46, and an example of an encoder signal when the carriage 12 is driven at a constant speed in that case and a detection speed detected based on the encoder signal. The detection speed shown in FIG. 4 is a detection result when the carriage 12 is moving in the right direction (forward direction) in the figure with respect to the linear scale 46 shown in FIG.

  In the example of FIG. 4, dirt 70 such as grease is attached to a certain area in the linear scale 46. Therefore, one slit 48 existing in the region where the dirt 70 is attached is covered with the dirt 70, and light from the light emitting elements 51 and 52 of the phases A and B is applied to the light receiving elements 61 and 62. It is out of reach.

  Therefore, while the carriage 12 is moving in the section corresponding to the area covered with the dirt 70, the encoder signal remains at a high level, and the rising edge and the falling edge that should be detected originally are detected. It is not detected and the count value is not updated. Thereby, although the carriage 12 is actually moving at a constant speed, the detection speed detected by the CR linear encoder processing unit 34 based on the encoder signal is the dirt 70 as shown in FIG. Fluctuated (decreased) significantly under the influence of The detected speed is also output to the CR motor control unit 32.

  Therefore, the CR motor control unit 32 performs feedback control for returning the greatly reduced detection speed to the target speed (constant speed). As a result, as shown in FIG. 4, the detection speed eventually converges to a constant speed while being damped.

  As described above, when the dirt 70 adheres to the linear scale 46, a speed different from the actual speed is detected as the detection speed of the carriage 12, and thereby unnecessary control is performed in the CR motor control unit 32. .

  Therefore, in the inkjet printer 1 of the present embodiment, the compensation control information setting unit 36 in the CR linear encoder processing unit 34 determines the presence or absence of dirt based on the detection speed of the carriage 12 and the case where dirt adhesion is detected. Specify the dirty section. When the dirt section is specified, thereafter, the CR motor control unit 32 performs compensation control in the dirt section.

(3) Explanation of Detection of Dirt Section and Compensation Control Next, detection of a dirt section to which dirt or the like is attached in the linear scale 46, which is performed by the compensation control information setting unit 36 in the CR linear encoder processing unit 34, Compensation control performed by the CR motor control unit 32 based on the detection result will be specifically described with reference to FIG. FIG. 5 shows an example in which dirt 71 and 72 are attached to two adjacent locations on the linear scale 46.

(3-1) Detection of Abnormal Speed When the carriage 12 is driven with the dirt 71 and 72 attached to the linear scale 46 as described above, the detection speed when the section corresponding to the dirt 71 and 72 is moved. Is greatly fluctuated as shown in FIG. 4 due to the influence of the stains 71 and 72, and deviates from a preset normal speed range (between the speed lower limit threshold and the speed upper threshold).

  Therefore, the compensation control information setting unit 36 monitors the detection speed of the carriage 12 detected by the CR linear encoder processing unit 34, and detects whether the detection speed is out of the normal speed range, that is, whether it is an abnormal speed. To do. If an abnormal speed is detected, it is determined whether the abnormal speed is caused by dirt on the linear scale 46 or some factor other than dirt (for example, disturbance such as load fluctuation). .

(3-2) Measurement of the total count value M at the time of abnormality, calculation of the dirt count value n, and determination of the cause of the abnormal speed Specifically, the determination of whether or not the abnormal speed is caused by dirt is as follows. Do as follows. First, the carriage 12 is driven in the entire area from one end to the other end of the movement path (scanning area), and the encoder signal is counted between them, thereby measuring the total count value M at the time of abnormality. In this embodiment, one end of the movement path means an end on the left side (adjustment area side) in FIG. 2, and the other end means an end on the right side (standby area side) in FIG. To do.

  On the other hand, in the EEPROM 6 (or in the ASIC 2), an encoder signal when the carriage 12 is driven in the entire scanning area from one end of the moving path to the other end when the linear scale 46 is in a normal state free from dirt and the like. Is stored in advance as a nominal count value N.

Therefore, the dirt count value n is obtained by performing the calculation of the following equation (1).
Dirt count value n = Nominal count value N-Abnormal total count value M (1)
When the dirt count value n is not 0, that is, when the abnormal total count value M is different from the nominal count value N, it is determined that the abnormal speed is caused by dirt on the linear scale 46. . On the contrary, when the dirt count value is 0, it is determined that the abnormal speed is detected due to a cause other than the dirt of the linear scale 46.

  FIG. 5 shows an example in which the nominal count value N is 1500, the abnormal total count value M is 1490, and therefore the dirt count value n is 10. In the example of FIG. 5, the total count value M at the time of abnormality is 10 less than the nominal count value N because the five slits 48 are covered by the dirts 71 and 72, so that they are originally counted by the five slits. This is because ten edge meters of the encoder signal to be detected are not detected.

  In FIG. 5, the dirt count value n becomes a positive value because the plurality of slits 48 are covered with dirt. However, as another case, dirt thinner than the width adheres to the slit 48, for example. For example, the slits 48 may be divided, and the number of slits may increase apparently. In such a case, contrary to the example of FIG. 5, the total count value M at the time of abnormality becomes larger than the nominal count value N, and therefore the dirt count value n becomes a negative value. Thus, even in the case where the number of slits apparently increases due to dirt and the total count value M at the time of abnormality becomes larger than the nominal count value N, it is based on whether they are different, that is, whether the dirt count value n is 0 or not. Thus, it can be determined whether or not the cause of the abnormal speed is dirt.

(3-3) Measurement of the first count value ka and the second count value kb and calculation of the dirt section width m After calculating the dirt count value n, the dirt section width m is calculated. Specifically, first, the carriage 12 is driven in the forward direction (toward the standby area) from one end side of the movement path. Then, the first count value ka is measured by counting the encoder signal from the start of driving at that time until the abnormal speed is detected. Next, the carriage 12 is driven in the opposite direction (toward the adjustment region) from the other end side of the movement path. Then, the second count value kb is measured by counting the encoder signal from the start of driving at that time until the abnormal speed is detected.

And the dirt section width m is calculated | required by calculating the following Formula (2).
Dirt section width m = nominal count value N −
(First count value ka + second count value Kb) (2)
FIG. 5 shows an example in which the first count value ka is 486, the second count value kb is 1000, and therefore the dirt section width m is 14. The dirt section width m is the width of the dirt section including the two dirts 71 and 72. In other words, the count value that would have been counted if there were no dirt 71 and 72 in the dirt section. That means.

  The dirty section width m can be calculated using the actual count value z in the dirty section obtained by the following expression (3), in addition to the method using the expression (2). That is, the dirt section width m can also be calculated by adding the dirt count value n to the dirt section actual count value z.

(3-4) Calculation of the actual count value z in the dirt section After the calculation of the dirty section width m, the actual count value z in the dirt section is calculated. Specifically, the actual count value z in the dirt section is obtained by performing the calculation of the following equation (3).

Actual count value z in dirt section = all count values M −
(First count value ka + second count value Kb) (3)
In FIG. 5, as an example, the case where the actual count value z in the dirt section is 4 is shown. In FIG. 5, not all the slits 48 are covered with dirt in the dirt section, and there are two slits 48 not affected by dirt between the two dirts 71 and 72. The edge of the encoder signal is detected four times. Therefore, the actual count value z in the dirt section is 4.

When the compensation control information setting unit 36 identifies the dirt section as described above, the compensation control information setting unit 36 transmits the identified information (dirty section information) to the CR motor control unit 32.
If the dirt count value is 0 when the dirt count value n is calculated by the above formula (1), that is, if the cause of the abnormal speed is something other than dirt, the next dirt section width m is calculated. Without performing the above, an error notification is given to an external user or the like by performing a predetermined error display on a display device (not shown) provided in the operation / display unit 8. Therefore, in this case, compensation control by the CR motor control unit 32 is not performed.

  In addition, when the dirt section width m is larger than a preset dirt width threshold when the dirt section width m is calculated by the above equation (2), the operation / display unit 8 determines that the dirt section width is too wide. An error notification is given to an external user or the like by displaying a predetermined error on a display device (not shown) provided. Also in this case, compensation control by the CR motor control unit 32 is not performed.

(3-5) Compensation Control by CR Motor Control Unit 32 When the dirt section information is transmitted from the compensation control information setting unit 36, the CR motor control section 32 uses the obtained dirt section as a compensation section, and thereafter the carriage 12 Is driven, compensation control using the holding operation amount is performed in the compensation section.

  That is, when the carriage 12 is driven from one end of the moving path, feedback control based on the detection speed is performed as usual until the compensation section (= dirt section) is entered. Specifically, an operation amount for controlling the CR motor 13 is calculated at a predetermined calculation timing based on the detected speed at that time, and a drive command corresponding to the operation amount is sent to the CR motor driver 16. Output.

  The determination as to whether or not the compensation period has been entered is made based on the count value of the encoder signal after the start of driving from one end side, and when the count value matches the first count ka, it is judged that the compensation period has been entered, Compensation control is started. In the example shown in FIG. 5, when the carriage 12 is driven from one end side, it can be determined that it has entered the compensation section when the count value of the encoder signal from the start of driving becomes 486.

  Compensation control within the compensation interval does not calculate the operation amount based on the detected speed, but generates a holding operation amount based on the operation amount actually calculated by the CR motor control unit 32 at the operation timing before entering the compensation interval. The control is performed by controlling the CR motor 13 according to the holding operation amount.

  The holding operation amount can be generated by various methods from the operation amount calculated before the start of the compensation interval.For example, the operation amount calculated at the calculation timing immediately before the start of the compensation interval may be used as the holding operation amount as it is. Further, for example, an average value of each operation amount calculated at a plurality of operation timings before the start of the compensation section may be used as the holding operation amount.

  While the compensation control is performed, the encoder signal is continuously counted. Therefore, after the count value reaches the first count value ka and enters the compensation section, when the carriage 12 passes the position corresponding to the two normal slits 48 existing between the dirt 71 and the dirt 72, the two The slit 48 increases the count value by four. This count value counted while passing through the compensation section is equal to the actual count value z in the dirt section.

  Therefore, the CR motor control unit 32 detects the end timing of the compensation section based on the count value after the start of compensation control. Specifically, it is determined whether the count value after entering the compensation section has reached the actual count value z in the dirt section. When the actual count value z in the dirt section is reached, it is the last count in the dirt section, so the compensation control is continued until the next count is performed. Then, after reaching the actual count value z in the dirt section, when the next count is performed, it is determined that the dirt section has exited (that is, the compensation section has exited), the compensation control is terminated, and normal feedback control is performed. Return.

Note that when the carriage 12 is driven from the other end side of the movement path, compensation control is performed in the compensation section in the same manner as when driving from the one end side described above.
(3-6) Correction of Count Value at Compensation Section End After the compensation section (dirty section), normal feedback control is resumed. The count value of the encoder signal at the end of the compensation section is that of dirt 71 and 72. Due to the influence, the value is different from the normal value with no dirt.

  In the numerical example of FIG. 5, the count value at the end of the compensation section when the carriage 12 is driven from one end side is set to the first count value ka if it is in a normal state without dirt 71 and 72. The value should be 501 which is a value obtained by adding 1 to the value obtained by adding the dirt section width m. However, due to the influence of the stains 71 and 72, the actual count value at the end of the compensation interval becomes 491 which is a value obtained by adding 1 to the value obtained by adding the actual count value z in the stain interval to the first count value ka. Yes. The difference between the two (difference between 501 and 491) corresponds to the dirt count value n.

  Therefore, when the feedback control is resumed with the count value after the end of the compensation section being the actual count value at that time (491 in FIG. 5), the feedback is performed while the position of the carriage 12 is detected as a position different from the actual position. Control is performed, and control performance may be deteriorated.

  Therefore, the compensation control information setting unit 36 corrects the actual count value at that time to the count value that should be at that time at the end of the compensation period. Specifically, at the end of the compensation period, the count value is corrected by adding the dirt count value n to the actual count value at that time. Thereby, after the compensation section is finished, there is no deviation between the actual position of the carriage 12 and the detected position (count value), and the subsequent feedback control can be performed stably.

Note that when the carriage 12 is driven from the other end side of the movement path, the count value is corrected after the compensation section is completed, just like the above-described driving from the one end side.
(3-7) Update of Compensation Section Start Position By the way, the compensation control information setting unit 36 sets the start position of the compensation section based on the first count value ka and the second count value kb. , Kb is based on the count value when the abnormal speed is detected. Therefore, depending on the timing at which the abnormal speed is detected, there is a possibility that the count value at the time of detection does not necessarily coincide with the start position of the dirt section. That is, the detection of the abnormal speed is performed by the CR linear encoder processing unit 34, but when the detection timing is delayed, it has already entered the dirt section and the count of one count or several counts has advanced in the dirt section. An abnormal speed may be detected.

  Therefore, when the detection of the abnormal speed is delayed in this way, and the compensation section start position is set based on the count value at the timing detected with the delay, even if it enters the area where dirt is actually attached The compensation control is not started immediately, and there is a risk that the detection speed fluctuates due to the influence of dirt.

  Therefore, as described above, the compensation control information setting unit 36 sets the start position of the compensation section (dirty section) based on the first count value ka and the second count value kb, and then compensates by the CR motor control unit 32. If an abnormal speed is still detected despite the control being performed, the start position of the compensation section is updated to a position before the currently set position (count value).

  For example, in the case where driving is started from one end side, when the compensation interval start timing is set to the first count value ka, the abnormal speed is increased before the compensation interval starts (that is, before the count value reaches the first count value ka). If it is detected, the compensation section start timing is advanced by one count to ka-1. Then, when driving is started again from one end side, compensation control is started from the position where the count value becomes ka-1.

  After the compensation section start position is updated in this way, if an abnormal speed is still detected before the compensation section is started, the compensation section start position is further advanced by one count to ka-2, and then once again. When starting driving from the side, compensation control is started from the position where the count value becomes ka-2. That is, the compensation section start position is sequentially updated (advanced) until no abnormal speed is detected before the start of the compensation section.

In addition, what is necessary is just to determine suitably how much it updates for every update, and updating for every 1 count as mentioned above is only an example to the last.
Further, when the compensation section start position is updated as described above, it is also preferable to update the dirt section width m and the dirt section actual count value z. For example, when the compensation section start position is advanced by one count, the dirt section width m and the dirt section actual count value z are also increased by one count. By doing so, it is possible to prevent the compensation control from being ended even though the compensation section start position is updated even though the compensation section start position is updated. Compensation control can be surely performed.

(4) Description of Carriage Driving Process Next, the carriage driving process performed in the ASIC 2 for controlling the driving of the carriage 12 will be described with reference to FIG. FIG. 6 is a flowchart showing a carriage driving process performed by the CR linear encoder processing unit 34 (particularly the compensation control information setting unit 36) and the CR motor control unit 32 in the ASIC 2. This carriage driving process is performed when an image formation instruction is given from an external PC or the like, or when an image formation instruction is given by an operation of the operation / display unit 8 or the like. It is performed in response to a command from

  When the carriage driving process is started, first, scanning (driving) of one line of the carriage 12 is started in S110. In S120, it is determined whether or not an abnormal speed has been detected when the carriage 12 has been driven in the past, that is, in the past execution of the carriage driving process. At this time, if an abnormal speed is detected in the determination process of S150 described later at the time of executing the past carriage drive process (S120: YES), the process proceeds to S170 and subsequent steps so that the compensation control is performed in the compensation section. However, when an abnormal speed has not been detected in the past (S120: NO), the process proceeds to S130, and normal-time drive control is performed. The normal driving control is normal feedback control based on the detection speed detected based on the encoder signal, and an operation amount is generated based on the detection speed. During the scanning for one line, the abnormal speed detection described in (3-1) above is performed at a constant cycle.

  Then, the normal time drive control in S130 is performed until the scanning for one line is completed, and when the scanning for one line is completed (S140: YES), an abnormal speed is detected during the scanning for one line in S150. Whether or not is detected is determined. Here, when the abnormal speed is detected (S150: YES), the process proceeds to S230 and subsequent steps, and a series of stain determination processes are performed. When the abnormal speed is not detected (S150: NO), the process proceeds to S160. Thus, it is determined whether or not all lines have been scanned. The process returns to S110 every time one line is scanned until all line scanning is completed. When all line scanning is completed (S160: YES), this carriage driving process is terminated.

  On the other hand, if it is determined in S150 that an abnormal speed has been detected during scanning for one line, it is determined in S230 whether or not the stain determination has already been performed. The contamination determination here is a series of processing for specifying a contamination interval (compensation interval) in S240 to S280.

  In S230, if the dirt determination has already been performed (S230: YES), the process proceeds to S310. If the dirt determination has not yet been performed (S230: NO), the process proceeds to S240 and subsequent, and the dirt determination is performed. .

  In the dirt determination, first, the dirt count value n is calculated in S240, and in subsequent S250, it is determined whether or not the cause of the abnormal speed is due to the dirt of the linear scale 46 based on the calculated dirt count value n. Judgment is made. The calculation of the dirt count value n in S240 and the determination of the cause of the abnormal speed in S250 are specifically performed as described in (3-2) above.

  If it is determined that the cause of the abnormal speed is not due to dirt because the dirt count value n is 0 (S250: NO), in S290, a display device (not shown) provided in the operation / display unit 8 is displayed. In step S300, the carriage 12 is stopped.

  If it is determined that the cause of the abnormal speed is due to dirt because the dirt count value n is not 0 (S250: YES), the dirt section width m is calculated in S260, and then in S270. Then, it is determined whether or not the calculated dirt section width m is larger than a predetermined dirt width threshold. The calculation of the dirt section width m in S260 is specifically performed as described in (3-3) above.

  If the dirt section width m is larger than the dirt width threshold value (S270: YES), it is assumed that dirt has adhered over a wide range, an error display is performed in S290, and the driving of the carriage 12 is stopped in the subsequent S300. Is done.

  When the dirt section width m is equal to or less than the dirt width threshold (S270: NO), the actual count value z in the dirt section is calculated in S280. The calculation of the actual count value z in the dirt section is specifically performed as described in (3-4) above.

  As described above, the dirt section width m can also be obtained by adding the dirt section actual count value z and the dirt count value n. Therefore, prior to the calculation of the dirt section width m in S260, the dirt section actual count value z is first calculated in S280, and then the dirt section width m is calculated by calculating m = z + n. Good.

  After the stain determination in S240 to S280 is performed in this way, the process returns to S110 again, and scanning for the next one line is started. For this reason, when the carriage is driven after the dirt determination is made, the abnormal speed is already detected in the previous carriage drive. Therefore, in the determination process of S120, it is determined that the abnormal speed has been detected, and the process proceeds to S170. become.

  In S170, it is determined whether or not the position of the carriage 12 is in the compensation section (dirt section). Until it enters the compensation section (S170: NO), in S180, the normal time control process is performed as in S130. Is done. Then, in S190, it is determined whether or not scanning for one line has been completed. If it has not been completed, the process returns to S170, and if it has been completed, the process proceeds to S150.

  When the carriage 12 enters the compensation section (S170: YES), the process proceeds to S200, and compensation control is started. Specifically, this compensation control is performed as described in (3-5) above, and control using the holding operation amount is performed instead of the operation amount based on the detection speed.

  While the carriage 12 is driven in the compensation section (S210: NO), the compensation control in S200 is continued, but when it is determined that the compensation section has been exited (end of the compensation section) (S210: YES). In S220, the detection position (count value) at the end of the compensation section is corrected, and the process proceeds to S190. Specifically, the correction in S220 is performed as described in (3-6) above.

Until the scanning for one line is completed after completion of the compensation period, it is determined in S170 that the current period is not the compensation period, and the normal time control process in S180 is executed again.
When the scanning for one line is completed after the compensation control is performed (S190: NO), it is again determined in S150 whether or not an abnormal speed is detected during the scanning for the one line. . Here, if the start position of the compensation section is set to a position that coincides with the actual dirt start position in the series of stain determination processes of S240 to S280, during the scanning for one line in which compensation control is performed. Although the abnormal speed should not be detected, as described in (3-7) above, the compensation start position does not always coincide with the actual dirt adhesion start position by only one stain determination.

  Therefore, if an abnormal speed is still detected even during scanning for one line for which compensation control has been performed (S150: YES), the process proceeds to S230. In this case, since the dirt determination has already been performed at least once, the process proceeds to S310, and the compensation section start position is updated. Specifically, the compensation section start position is updated as described in (3-7) above.

After the compensation section start position is updated in this way, the process returns to S110 again, and scanning for the next one line is started.
(5) Effects of Embodiments As described above, in the inkjet printer 1 of the present embodiment, when an abnormal speed is detected while the carriage 12 is being driven, a section in which dirt or the like on the linear scale 46 is attached ( A dirty section) is identified. When the carriage 12 is driven after the abnormal speed is detected, the dirt section is used as the compensation section, and compensation control using the holding operation amount is performed in the compensation section.

  For this reason, it is possible to prevent the influence of fluctuations in the detection speed caused by the dirt or the like from being reflected in the control of the CR motor 13 in the section (compensation section) where the dirt or the like is adhered, and the carriage 12 is stabilized. Can be driven.

  In addition, the control of the CR motor 13 using the holding operation amount is performed only within the compensation section. That is, when the compensation section is completed, normal control is performed again with the operation amount calculated based on the detection speed. Further, the end timing of the compensation section is accurately detected based on the count value of the encoder signal after the start of the compensation section and the actual count value z in the dirt section.

  Therefore, the drive control of the CR motor 13 by the holding operation amount can be performed sufficiently and sufficiently, and the deterioration of the control performance as a whole is greatly suppressed, and the control of the CR motor 13 and thus the drive control of the carriage 12 are performed with high accuracy. Can do.

  Further, the holding operation amount used in the compensation section is based on the fact that the CR motor controller 32 actually calculates the carriage 12 before entering the compensation section, considering the sliding load of the carriage 12 before entering the compensation section. Appropriate value. Therefore, by using such a holding operation amount in the compensation section, it is possible to give a more appropriate driving force to the carriage 12 even in the compensation section.

  In the present embodiment, when the compensation section ends (when the carriage 12 exits the compensation section), the count value of the encoder signal is added to the actual count value at that time, and the dirt count value n is added at that time. The count value is corrected to a proper value (value indicating the original position). Therefore, the deviation between the actual position of the carriage 12 after passing through the compensation section and the count value can be eliminated, and the drive control of the carriage 12 after passing through the compensation section can be influenced by the influence of the compensation section (effect of dirt, etc.). It can be performed with higher accuracy without receiving.

  Further, in this embodiment, when the dirt count value n is 0, an error notification is given to an external user and the like because the abnormal speed is caused by something other than the dirt of the linear scale 46, and the carriage 12 is driven. I try to stop it. Therefore, the user or the like can be informed that an abnormality due to factors other than the CR linear encoder 14 has occurred, and can be prompted to take an appropriate action in accordance with the abnormality.

  Further, even when the dirt section width m is larger than the dirt width threshold, the carriage 12 is stopped by notifying the user or the like that the dirt section width m is too wide. Therefore, it is possible to prevent deterioration of control performance that can be caused by driving the carriage 12 with a holding operation amount over a wide range, and it is possible to prompt a user or the like to take an appropriate measure.

  In the present embodiment, when the carriage 12 is driven after the dirt section (compensation section) is set by detecting the abnormal speed, the abnormal speed is detected again before entering the set compensation section. The start position of the compensation section is updated to a position before the currently set position (count value). For this reason, even if the start position of the compensation section once set is deviated from the position where dirt or the like actually starts to adhere, the deviation can be corrected.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. In the present embodiment, the CR linear encoder processing unit 34 corresponds to the drive state detection unit of the present invention, the CR motor control unit 32 corresponds to the operation amount calculation unit and the operation amount compensation unit of the present invention, and the nominal count value N is The stored EEPROM 6 (or ASIC 2) corresponds to storage means of the present invention, and the operation / display unit 8 corresponds to first notification means and second notification means of the present invention.

  Further, the compensation control information setting unit 36 includes an abnormal speed detecting means, a compensation section detecting means, an abnormal total count value measuring means, a compensation actual count value calculating means, an abnormal count error detecting means, a correcting means, and a compensation means. It corresponds to a section width calculating means, a compensation section width determining means, and an updating means.

  In the carriage driving process of FIG. 6, the normal driving control in S130 and S180 corresponds to the process executed by the operation amount calculating means of the present invention, and the compensation control of S200 is the process executed by the operation amount compensating means of the present invention. The correction of the compensation end position in S220 corresponds to the processing executed by the correcting means of the present invention, and the calculation of the dirt count value n in S240 corresponds to the processing executed by the abnormal time count error detecting means of the present invention. , The calculation of the dirt section width m in S260 corresponds to the process executed by the compensation section width calculation means of the present invention, the determination process in S270 corresponds to the process executed by the compensation section width determination means of the present invention, and the dirt in S280. The calculation of the actual count value z within the interval corresponds to the processing executed by the actual count value calculation unit within the compensation interval of the present invention, and the update of the compensation interval start position of S310 is executed by the update means of the present invention. It corresponds to the physical.

[Modification]
Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments, and can take various forms as long as they belong to the technical scope of the present invention. Needless to say.

  For example, in the above-described embodiment, as a specific example of encoder contamination, as illustrated in FIG. 5, contamination 71 and 72 adhere to two adjacent locations on the linear scale 46 and the slit 48 within the attached range is contaminated. Although the case where it has been covered has been described, even if the number of places where dirt is attached is one place or more than three places, the dirt section (compensation section) is identified and compensated in the same manner as in the above embodiment. Control can be performed.

  Further, in the above embodiment, the case where the slit 48 is covered with dirt, that is, the case where the edge of the encoder signal that should be counted is not counted is illustrated. There may be a case in which more edges than the edges that should be counted are detected and counted because finer dirt adheres. As described above, even in the case where the count is larger than the original count due to contamination, it is possible to specify the contamination interval (compensation interval) and perform compensation control in the same manner as in the above embodiment.

  In other words, the present invention is applied regardless of how much dirt is deposited and how many count values are counted more or less due to the dirt. be able to.

  In the above embodiment, among the A and B phase pulse signals from the CR linear encoder 14, the rising edge and the falling edge of the A phase signal are counted, but this is only an example. For example, only either the rising edge or the falling edge may be counted, or the B-phase signal may be counted instead of the A-phase signal. Further, both the rising edge and the falling edge of the pulse signals of the A and B phases may be counted.

  In the above embodiment, the example in which the present invention is applied to the control of the CR motor 13 for driving the carriage 12 in the inkjet printer 1 has been described. However, the present invention is applied to the motor control for driving the carriage or the inkjet printer. The present invention is not limited to the motor control in, and can be applied to any motor control apparatus configured to control the motor by detecting the movement amount of the drive target using a linear encoder.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet printer, 2 ... ASIC, 3 ... CPU, 4 ... ROM, 5 ... RAM, 6 ... EEPROM, 7 ... I / F, 8 ... Operation / display part, 9 ... Bus, 11 ... Recording head, 12 ... Carriage , 13 ... CR motor, 14 ... CR linear encoder, 15 ... recording head driver, 16 ... CR motor driver, 21 ... LF motor, 22 ... LF rotary encoder, 23 ... LF motor driver, 31 ... recording control unit, 32 ... CR Motor control unit, 33 ... LF motor control unit, 34 ... CR linear encoder processing unit, 35 ... LF rotary encoder processing unit, 36 ... compensation control information setting unit, 41 ... guide shaft, 42 ... endless belt, 43 ... drive pulley, 44 ... driven pulley, 46 ... linear scale, 47 ... detecting section, 48 ... slit, 50 ... light emitting section, 51 ... A phase light emitting element, 52 B-phase light-emitting element, 60 ... light-receiving unit, 61 ... A phase light-receiving element, 62 ... B-phase light-receiving element, 70, 71, 72 ... dirt, P ... paper

Claims (11)

A linear encoder that outputs a pulsed encoder signal according to the amount of movement of a driven body driven by a motor on a preset movement path;
Drive state detection means for counting the encoder signal from the linear encoder and detecting the speed and position of the driven body based on the count value;
An operation amount calculation means for calculating an operation amount for controlling the motor based on a detection speed by the drive state detection means at every predetermined calculation timing and outputting the operation amount to the motor;
A motor control device comprising:
An abnormal speed detecting means for detecting whether or not the detection speed detected by the drive state detecting means is an abnormal speed deviating from a preset normal speed range;
When the abnormal speed is detected by the abnormal speed detecting means, the driven body is driven from one end of the moving path, and the encoder signal is counted until the abnormal speed is detected by the abnormal speed detecting means. And measuring the first count value ka and driving the driven body from the other end of the moving path to count the encoder signal until the abnormal speed is detected by the abnormal speed detecting means. Compensation period detecting means for measuring the second count value kb and detecting between the positions corresponding to the respective count values ka and kb as a compensation period;
When driving the driven body after the compensation section is detected by the compensation section detecting means, it is determined whether the driven body has entered the compensation section based on a detection position by the driving state detecting means. At the same time, when entering the compensation section, within the compensation section, the operation amount is obtained based on one or a plurality of operation amounts calculated by the operation amount calculating means before entering the compensation section. An operation amount compensation means for outputting an operation amount;
A motor control device comprising: The motor control device according to claim 1,
When the abnormal speed is detected by the abnormal speed detecting means, the driven body is driven in the entire region from one end to the other end of the moving path, and the abnormal encoder is counted by counting the encoder signal being driven. An abnormal total count value measuring means for measuring the total count value M at the time,
A compensation interval actual count value calculating means for calculating a compensation interval actual count value z by subtracting the sum of the first count value ka and the second count value kb from the abnormal total count value M;
When the driven body enters the compensation section, the manipulated variable compensation means determines the end position of the compensation section based on the count value by the drive state detection means after entering the compensation section and the actual count value z in the compensation section. The motor control device is characterized in that the holding operation amount is output until the end position is detected. The motor control device according to claim 2,
When the linear encoder is normal, when the driven body is driven in the entire region from one end to the other end of the moving path, a nominal count value N which is a count value of the encoder signal being driven is Storage means stored in advance;
When the abnormal speed is detected by the abnormal speed detecting means, the abnormal count is subtracted from the nominal count value N by subtracting the abnormal total count value M measured by the abnormal total count value measuring means. An abnormal time count error detecting means for detecting an error n;
When the driven body is driven after the compensation section is detected by the compensation section detecting means, the count value being counted by the driving state detecting means is calculated when the driven body leaves the compensation section. Correcting means for correcting to a value obtained by adding the abnormal count error n to the count value when the compensation section is exited;
A motor control device comprising: The motor control device according to claim 3,
The operation amount compensation means outputs the holding operation amount when the abnormal time count error n is not zero. The motor control device according to claim 4,
A motor control device comprising: first notification means for performing predetermined notification based on the detection result when the abnormality count error n is detected as 0 by the abnormality count error detection means. . In the motor control device according to any one of claims 3 to 5,
By subtracting the sum of the first count value ka and the second count value kb from the nominal count value N, a compensation interval width m which is a count value that should be originally counted by the driving state detection means in the compensation interval. Compensation interval width calculating means for calculating
Compensation interval width judging means for judging whether or not the compensation interval width m detected by the compensation interval width calculating means is larger than a preset compensation interval width threshold;
With
The operation amount compensation unit outputs the holding operation amount when the compensation interval width determination unit determines that the compensation interval width m is equal to or less than the compensation interval width threshold value. The motor control device according to claim 6,
When the compensation section width determining means determines that the compensation section width m is larger than the compensation section width threshold, the second section is provided with a second notification means for performing a predetermined notification based on the determination result. Motor control device. In the motor control device according to any one of claims 1 to 7,
When the abnormal speed is detected by the abnormal speed detection means before the driven body enters the compensation section when the driven body is driven after the compensation section is detected by the compensation section detection means. In addition, the motor control device further includes an update unit that updates the start position of the compensation section to a position that is a predetermined amount before the currently detected position. In the motor control device according to any one of claims 1 to 8,
The operation amount compensation means outputs the operation amount calculated by the operation amount calculation means at the calculation timing immediately before the driven body enters the compensation section as the holding operation amount. apparatus. In the motor control device according to any one of claims 1 to 8,
The manipulated variable compensation means outputs, as the holding manipulated variable, an average value of the manipulated variables calculated by the manipulated variable calculator at a plurality of the calculation timings before the driven body enters the compensation section. A motor control device. The motor control device according to any one of claims 1 to 10,
A recording head that forms an image on a recording medium by ejecting ink; and
A carriage on which the recording head is mounted as the driven body;
An image forming apparatus comprising: