JP7655045B2 - Control System - Google Patents

Description

This disclosure relates to a control system.

Conventionally, in inkjet printers that form images on a sheet by reciprocating an inkjet head in the main scanning direction, a technique is known that aims to speed up the printing process by increasing the movement speed of the carriage carrying the inkjet head in non-image areas sandwiched between image areas (see, for example, Patent Document 1).

JP 2005-22115 A

In systems such as inkjet printers, in which a carriage carrying a processing head is moved back and forth to process a sheet that crosses the carriage's movement path, a jam can occur, which is a contact event in which the carriage or processing head comes into contact with the sheet, due to the curvature of the sheet, etc.

One possible method for detecting this jam is to use the deviation between the target speed of the carriage and the actual speed of the carriage measured by a measuring device. When a jam occurs, the carriage's movement is hindered by the sheet it comes into contact with, causing the carriage speed to decrease. Therefore, a jam can be detected by monitoring the deviation.

However, with conventional detection methods based on deviation, the detection accuracy deteriorates when the carriage is accelerating or decelerating. This is because in the acceleration/deceleration section, even if no jam has occurred, the deviation is likely to become large due to a delay in the tracking of the actual speed relative to the target speed.

Therefore, according to one aspect of the present disclosure, it is desirable to provide a technology that can properly detect contact events between a moving body and a sheet in a system that processes a sheet by reciprocating a moving body.

According to one aspect of the present disclosure, a control system is provided. The control system includes a motor, a moving body, a measuring instrument, and a controller. The moving body is configured to be driven by the motor and to reciprocate in a first direction.

The moving body is configured to process a sheet transported in a second direction intersecting the first direction so as to cross a path of movement of the moving body. The measuring device is configured to measure a speed of the moving body. The controller is configured to control the motor based on the speed profile.

According to one aspect of the present disclosure, the controller can be configured to calculate an operation amount for the motor based on the deviation between a target speed of the moving body according to the speed profile and the speed measured by the measuring instrument, and to control the motor so that the moving body reciprocates according to the operation amount by supplying power to the motor according to the operation amount, and to detect the occurrence of an event in which the moving body comes into contact with the sheet, on condition that the operation amount exceeds a preset threshold value.

When the moving body accelerates or decelerates, the deviation tends to become large due to a delay in the actual speed following the target speed. Therefore, when detecting the occurrence of an event in which the moving body comes into contact with a sheet based on a comparison between the deviation and a threshold, the detection accuracy of the event decreases when the moving body accelerates or decelerates. If the threshold is increased to suppress false detections, the detection sensitivity of the event when the moving body is moving at a constant speed decreases.

In contrast, by detecting the occurrence of an event in which a moving object comes into contact with a sheet based on the amount of operation, it is possible to detect the occurrence of the event with high accuracy or sensitivity, suppressing the effects of the tracking delay, particularly when the moving object is accelerating or decelerating, compared to detecting the occurrence of the event based on a comparison between the deviation and a threshold value. Therefore, according to one aspect of the present disclosure, it is possible to provide a system that can appropriately detect the occurrence of a contact event between a moving object and a sheet.

According to another aspect of the present disclosure, the controller may be configured to calculate an operation amount for the motor based on the deviation between a target speed of the moving body according to the speed profile and the speed measured by the measuring instrument, and to control the motor by supplying power according to the operation amount to the motor so that the moving body reciprocates according to the target speed, and to detect the occurrence of an event in which the moving body comes into contact with the sheet, on condition that the deviation exceeds a preset threshold value.

According to another aspect of the present disclosure, when the speed profile defines target speeds in multiple sections in which at least one of the height and the change in the target speed is different, the threshold may be set individually for each of the multiple sections. The controller may detect the occurrence of an event in each of the multiple sections on the condition that the deviation exceeds the threshold set for the corresponding section.

By detecting the occurrence of an event in which a moving object comes into contact with a sheet based on a comparison between a threshold value corresponding to the section and the deviation, it is possible to reduce the effects on detection accuracy and sensitivity caused by the deviation increasing when the moving object accelerates or decelerates, and it is possible to properly detect an event in which the moving object comes into contact with a sheet.

1 is a block diagram showing a configuration of an image forming system 1. FIG. FIG. 2 is an explanatory diagram of a carriage transport mechanism and a paper transport mechanism. 11 is a flowchart showing a printing process executed by a processor. FIG. 2 is a block diagram illustrating a configuration of a CR motor control unit. FIG. 2 is a block diagram showing a configuration of a speed controller. 11 is a flowchart showing a profile setting process executed by a processor. FIG. 13 shows a graph of velocity versus time (top) illustrating the velocity profile and a graph of threshold versus time (bottom) illustrating threshold change. 10 is a flowchart showing a jam detection process executed by a processor. 6 is a flowchart showing a jam-related process executed by a processor. 11 is a flowchart illustrating a jam detection process according to a first modified example. 10 is a flowchart showing a jam detection process according to a second modified example. 13 is a flowchart showing a jam detection process according to a third modified example. FIG. 11 is an explanatory diagram regarding dirt adhering to an encoder scale. 13 is a flowchart showing a jam detection process according to a fourth modified example.

Exemplary embodiments of the present disclosure will now be described with reference to the drawings.
1 is an inkjet printer that forms an image by ejecting ink droplets onto a sheet of paper P to be processed. The image forming system 1 includes a processor 11, a ROM 12, a RAM 13, an EEPROM 15, a user interface 17, a communication interface 19, and an ASIC 20. The ASIC 20 includes a recording control unit 21, a CR (carriage) motor control unit 31, and an LF (line feed) motor control unit 35.

The image forming system 1 further includes a recording head 22 and a drive circuit 23 as components for forming an image on paper P. The image forming system 1 further includes a carriage transport mechanism 40, a CR motor 51, a drive circuit 53, and an encoder 55 as components for moving the recording head 22 in the main scanning direction. The carriage transport mechanism 40 includes a carriage 41 that carries the recording head 22.

The image forming system 1 further includes a paper transport mechanism 60, an LF motor 71, a drive circuit 73, and an encoder 75 as components for transporting the paper P in a sub-scanning direction perpendicular to the main scanning direction.

The processor 11 performs overall control of the image forming system 1 and realizes various functions by executing processes according to computer programs recorded in the ROM 12. The ROM 12 stores various computer programs. The RAM 13 is used as a working memory when the processor 11 executes processes. The EEPROM 15 is a non-volatile memory that allows electrically rewriting data, and stores various setting information.

The user interface 17 includes an operation unit that can be operated by the user and a display unit that can display various information to the user. The communication interface 19 is configured to be capable of communicating with an external device such as a personal computer.

Each time a print command is received from an external device, the processor 11 executes a print process (see FIG. 3), the details of which will be described later. In the print process, the processor 11 causes the recording control unit 21 to control the ejection of ink droplets from the recording head 22, causes the CR motor control unit 31 to control the movement of the carriage 41 by controlling the CR motor 51, and causes the LF motor control unit 35 to control the transport of the paper P by controlling the LF motor 71. As a result, an image is formed on the paper P based on the data to be printed that the processor 11 received from the external device.

The recording head 22 (see FIG. 1) is a processing head for printing the paper P, and is specifically an inkjet head with multiple nozzles arranged for ejecting ink droplets. The recording head 22 is driven by a drive circuit 23, and prints the paper P by ejecting ink droplets onto the opposing paper P along the movement path of the carriage 41.

Based on instructions from the processor 11, the recording control unit 21 inputs a control signal to the drive circuit 23 and controls the ejection of ink droplets by the recording head 22 so that an image based on the data to be printed is formed on the paper P.

As shown in FIG. 2, the carriage transport mechanism 40 includes a carriage 41 that carries the recording head 22, a guide rail 42, and a belt mechanism 43. The carriage transport mechanism 40 is driven by a CR motor 51 to reciprocate the carriage 41 in the main scanning direction.

The guide rail 42 is configured to limit the movement of the carriage 41 in the main scanning direction. The belt mechanism 43 includes a drive pulley 431, a driven pulley 433, and a belt 435 wound between the drive pulley 431 and the driven pulley 433. The carriage 41 is fixed to the belt 435.

In the belt mechanism 43, the drive pulley 431 rotates by receiving power from the CR motor 51, and the belt 435 and driven pulley 433 rotate in accordance with the rotation of the drive pulley 431. This rotation moves the carriage 41 in the main scanning direction along the guide rail 42.

The CR motor 51 is, for example, a DC motor, and is driven by a drive circuit 53. The drive circuit 53 supplies the CR motor 51 with power according to a control signal input from the CR motor control unit 31, and more specifically, applies a voltage according to the control signal to the CR motor 51 to drive the CR motor 51.

The CR motor control unit 31 operates according to instructions from the processor 11, and controls the CR motor 51 so that the carriage 41 moves in the main scanning direction at a speed that follows the speed profile specified by the processor 11. At this time, the CR motor control unit 31 feedback controls the speed of the carriage 41 based on the encoder signal input from the encoder 55.

The encoder 55 is configured as a linear encoder. The encoder 55 includes an encoder scale 55A provided along the guide rail 42 and an optical sensor 55B mounted on the carriage 41.

The encoder 55 outputs a pulse signal corresponding to the displacement of the carriage 41 in the main scanning direction as an encoder signal. The CR motor control unit 31 measures the position and speed of the carriage 41 in the main scanning direction based on this encoder signal, and controls the movement of the carriage 41 in the main scanning direction through control of the CR motor 51.

2, the paper transport mechanism 60 includes a roller 61 having an axis parallel to the main scanning direction, which is driven by the LF motor 71 to rotate in the sub-scanning direction. The paper transport mechanism 60 transports paper P, which is supplied one sheet at a time from a tray, in the sub-scanning direction by the rotation of the roller 61, and supplies the paper P to a position where ink droplets are ejected by the recording head 22. The paper transport mechanism 60 transports the paper P in stages in the sub-scanning direction so as to cross the movement path of the carriage 41 in the main scanning direction.

The LF motor 71 is, for example, a DC motor, and is driven by a drive circuit 73. The drive circuit 73 drives the LF motor 71 according to a control signal input from the LF motor control unit 35.

The LF motor control unit 35 generates a control signal for the drive circuit 73 and controls the LF motor 71 according to instructions from the processor 11. The LF motor control unit 35 controls the transport of the paper P by feedback control based on an output signal from an encoder 75, which is a rotary encoder provided in the LF motor 71, the roller 61, or the transmission system between them.

Next, the details of the print process that the processor 11 executes each time it receives a print command will be described with reference to FIG. 3. When the processor 11 starts the print process, it executes a page print process (S110-S170) for each page.

In S110, the processor 11 executes a paper feed process. In the paper feed process, the processor 11 causes the LF motor control unit 35 to control the LF motor 71 so that a sheet of paper P is separated from a paper feed tray (not shown) and transported in the sub-scanning direction to the position where ink droplets are ejected by the recording head 22. The processor 11 further places the carriage 41, which is located at the home position, in the initial position through the control of the CR motor 51 by the CR motor control unit 31 (S120).

Then, the processor 11 sets a speed profile in the CR motor control unit 31 that defines the target speed Vr from the movement start point of the carriage 41 to the target stopping point (S130). Furthermore, the processor 11 executes main scanning direction printing (S140).

In S140, the processor 11 instructs the CR motor control unit 31 to control the CR motor 51 according to the speed profile set in S130. The processor 11 further inputs image data representing one pass of an image to be formed on the paper P to the recording control unit 21, and instructs the recording control unit 21 to control the ink droplet ejection operation by the recording head 22 based on this image data.

The image for one pass to be formed on the paper P is the image to be formed on the paper P by the ejection of ink droplets as the carriage 41 moves in the main scanning direction from one turning point to another.

By this command, the CR motor control unit 31 controls the CR motor 51 so that the carriage 41 moves from the movement start point to the next turning point corresponding to the target stopping point along a speed trajectory that follows the speed profile set above.

Specifically, the CR motor control unit 31 feedback controls the speed of the carriage 41 based on the speed profile. The CR motor control unit 31 calculates the deviation E = Vr - V between the target speed Vr according to the speed profile and the speed V of the carriage 41 measured based on the encoder signal.

The CR motor control unit 31 calculates the operation amount U for the CR motor 51 based on the deviation E and further based on the time derivative of the target speed Vr, and inputs a corresponding control signal to the drive circuit 53. The operation amount U is a value that represents the drive power to be applied to the CR motor 51, specifically, the drive voltage to be applied to the CR motor 51.

The recording control unit 21 controls the recording head 22 so that the ink droplet ejection operation for forming an image corresponding to the image data is performed by the recording head 22 in accordance with the movement of the carriage 41. By executing main scanning direction printing in S140, an image for one pass based on the image data is formed on the paper P.

When the main scanning direction printing in S140 is completed, the processor 11 determines whether the printing process for one page of the paper P is complete (S150). If it is determined that the printing process is not complete (No in S150), the processor 11 causes the LF motor control unit 35 to control the LF motor 71 so as to transport the paper P in the sub-scanning direction a predetermined distance corresponding to the width of the image for one pass in the sub-scanning direction (S160).

After executing the process of S160, the processor 11 sets the speed profile to be used in the next main scanning direction printing (S130). After setting the speed profile, the processor 11 executes main scanning direction printing (S140) to form an image for one pass on the paper P that was sent a predetermined distance in the sub-scanning direction by the process of S160 just before.

The processor 11 repeatedly executes the processes of S130-S160 until it determines that printing of one page of paper P is complete. In this way, an image for one page is printed on the paper P with the reciprocating movement of the carriage 41, the ejection of ink droplets, and the transport of the paper P. When the processor 11 determines that printing of one page of paper P is complete (Yes in S150), it executes the process of S170.

In S170, the processor 11 executes a paper ejection process for the printed paper P. In the paper ejection process, the LF motor 71 is controlled via the ASIC 20 to eject the printed paper P onto an ejection tray (not shown).

The processor 11 further determines whether the data to be printed contains page image data for the next page (S180), and if it determines that the data contains page image data for the next page (Yes in S180), it executes the page printing process for the next page (S110-S170).

In this way, the processor 11 forms an image based on the data to be printed on the paper P for each page, and when the page printing process for all pages is completed (No in S180), the printing process ends.

Next, the detailed configuration of the CR motor control unit 31 will be described with reference to Figures 4 and 5. As shown in Figure 4, the CR motor control unit 31 includes a signal processing circuit 110, a command generator 120, a speed controller 130, and a jam detector 140.

The signal processing circuit 110 is configured to measure the position X and velocity V of the carriage 41 in the main scanning direction based on the encoder signal from the encoder 55. The command generator 120 is configured to input to the speed controller 130, in accordance with the speed profile set by the processor 11, a speed command value Vr which is the target speed Vr at each time point from the start of control of the movement of the carriage 41 associated with printing in the main scanning direction, an acceleration command value Ar corresponding to the first-order time differential of the speed command value Vr, and a jerk command value Yr corresponding to the second-order time differential of the speed command value Vr.

According to one example, the processor 11 can set to the command generator 120 not only a speed profile, but also an acceleration profile that defines a target acceleration Ar corresponding to the target speed Vr, and a jerk profile that defines a target jerk Yr corresponding to the target speed Vr.

The speed controller 130 calculates a voltage command value representing the drive voltage to be applied to the CR motor 51 as the operation amount U for the CR motor 51 based on the speed command value Vr, acceleration command value Ar, and jerk command value Yr, and the measured speed V input from the signal processing circuit 110, and inputs a corresponding control signal to the drive circuit 53.

The speed controller 130 shown in FIG. 5 includes a subtractor 210, a gain amplifier 220, adders 230, 240, and 250, and a disturbance observer 290. The subtractor 210 outputs the deviation E=Vr-V between the speed command value Vr and the measured speed V of the carriage 41. The deviation E is amplified by the gain Kv in the gain amplifier 220, and then output from the gain amplifier 220.

The output Kv·E of the gain amplifier 220 is converted to a manipulated variable (Kv·E+Ar+Yr) by passing through adders 230 and 240 and adding the acceleration command value Ar and the jerk command value Yr. Furthermore, the manipulated variable (Kv·E+Ar+Yr) is added to the disturbance estimate value d calculated by the disturbance observer 290 in the adder 250. The manipulated variable after the addition (Kv·E+Ar+Yr+d) is output from the speed controller 130 as the manipulated variable U.

The disturbance observer 290 calculates a disturbance estimated value d=U−U* as the difference U−U* between the manipulated variable U ^* corresponding to the measured speed V, which is calculated using an inverse model of the transfer function from the manipulated variable U to the speed V ^, and the manipulated variable U which is the output of the speed controller 130, and inputs the calculated disturbance estimated value d=U−U ^* to the adder 250.

In this way, the speed controller 130 calculates the operation amount U taking into account the deviation E, the acceleration command value Ar, the jerk command value Yr, and the disturbance in order to realize the movement of the carriage 41 according to the speed profile, and drives the CR motor 51 with the corresponding drive voltage via the drive circuit 53.

In addition, the jam detector 140 is configured to detect the occurrence of a paper jam (hereinafter simply referred to as a jam), which is an event in which the recording head 22 comes into contact with the paper P, based on the deviation E and the operation amount U calculated by the speed controller 130.

Next, the details of the profile setting process executed by the processor 11 in S130 will be described with reference to FIG. 6. By executing the profile setting process, the processor 11 sets the speed profile to be used in the next main scanning direction printing, and also sets a threshold value set Th for jam detection.

When the profile setting process starts, the processor 11 determines the ink ejection section of the movement path from the movement start point of the carriage 41 to the target stopping point for the next main scanning direction printing, where the ink droplet ejection operation is performed by the recording head 22 (S210).

The processor 11 further determines whether the distance from the end point of the ink ejection section to the target stopping point is equal to or greater than a predetermined distance required for high-speed movement (S220). If it is determined that it is equal to or greater than the predetermined distance (Yes in S220), the processor 11 generates a speed profile having the shape shown in the upper part of FIG. 7, and sets the generated speed profile in the CR motor control unit 31 (S230). The speed profile generated in S230 (hereinafter also referred to as the first speed profile) is a speed profile with high-speed movement that has the following characteristics:

The acceleration section includes an acceleration section in which the carriage 41 is accelerated from the movement start point to the first velocity Vr1. The end point of the acceleration section is before the start point of the ink ejection section.
The period from when the carriage 41 finishes accelerating to the first velocity Vr1 until when the carriage 41 reaches the end point of the ink ejection period includes a first constant velocity period in which the carriage 41 moves at a constant speed at the first velocity Vr1.
Immediately after the carriage 41 passes the end point of the ink ejection section, a re-acceleration section is included in which the carriage 41 is accelerated to a predetermined second velocity Vr2 that is higher than the first velocity Vr1.
- The period from the end of acceleration of the carriage 41 to the second speed to the time when the carriage 41 reaches the deceleration start point which is the distance before the target stopping point required for deceleration includes a second constant speed section in which the carriage 41 moves at a constant speed of the second speed Vr2.
The deceleration section includes a deceleration section in which the carriage 41 decelerates and stops toward the target stopping point, starting immediately after the carriage 41 reaches the deceleration start point.

In the next step S240, the processor 11 sets a threshold value group Th of the operation amount U for jam detection corresponding to the speed profile set in S230 for the jam detector 140. Specifically, as the threshold value group Th, threshold values are set for each of a plurality of sections in which at least one of the height and the change in the target speed Vr in the speed profile is different.

That is, the processor 11 sets a threshold value Th1 in the acceleration section, a threshold value Th2 in the first constant speed section, a threshold value Th3 in the re-acceleration section, a threshold value Th4 in the second constant speed section, and a threshold value Th5 in the deceleration section.

The equation of motion of the carriage 41 is expressed as follows: In the following equation, dv/dt represents the time derivative of v, v represents the velocity of the carriage 41, m represents the mass, c represents the viscous friction coefficient, and f _c represents Coulomb friction.

キャリッジ４１に作用するＣＲモータ５１の力ｆは、ＣＲモータ５１の駆動電圧に比例する。

The force f of the CR motor 51 acting on the carriage 41 is proportional to the drive voltage of the CR motor 51 .

From this, it can be seen that in the section where the carriage 41 is moved at a constant speed, it is necessary to apply a drive voltage to overcome the viscous friction and Coulomb friction corresponding to the target speed Vr, and in the section where the carriage 41 is accelerated or decelerated, it is further necessary to apply an additional drive voltage to apply the force required for acceleration and deceleration to the carriage 41.

The operation amount U is calculated to increase or decrease by the speed controller 130 according to this principle. If a jam occurs while the carriage 41 is moving in the main scanning direction, the operation amount U changes in an upward direction due to contact between the paper P and the carriage 41 or the recording head 22. In this embodiment, in order to detect a jam based on the increase in the operation amount U caused by this jam, individual thresholds Th1-Th5 are set for each section as described above.

The graph shown in the lower part of Figure 7 is a graph explaining the threshold values Th1-Th5 of each section corresponding to the speed profile shown in the upper part of Figure 7. As can be understood from the above principle, when the speed profile shown in the upper part of Figure 7 is set, as shown in the lower part of Figure 7, the threshold value Th3 of the re-acceleration section is set to the highest of all sections, followed by the threshold value Th1 of the acceleration section, which is set to the next highest. For the first and second constant speed sections in which the carriage 41 moves at a constant speed, the threshold value Th4 of the second constant speed section, in which the target speed Vr is high and viscous friction is high, is set higher than the threshold value Th2 of the first constant speed section.

These thresholds Th1-Th5 are determined in advance, for example, by adding a predetermined amount to the operation amount U of each section when no jam has occurred, and are recorded in ROM 12 or EEPROM 15. Taking into account changes over time, the thresholds Th1-Th5 may be updated based on the operation amount U obtained by moving the carriage 41 according to the above speed profile when the image forming system 1 is started up and it is estimated that no paper P is present.

If it is determined in S220 that the distance from the end point of the ink ejection section to the target stopping point is less than the predetermined distance required for high-speed movement (No in S220), the processor 11 generates a speed profile without high-speed movement and sets the generated speed profile in the CR motor control unit 31 (S250). The speed profile generated in S250 (hereinafter also referred to as the second speed profile) specifically has the following characteristics:

The acceleration section includes an acceleration section in which the carriage 41 is accelerated from the movement start point to the first velocity Vr1. The end point of the acceleration section is before the start point of the ink ejection section.
- The period from the end of acceleration of the carriage 41 to the first speed Vr1 to the time when the carriage 41 reaches the deceleration start point that is the distance before the target stopping point required for deceleration includes a constant speed section in which the carriage 41 moves at a constant speed at the first speed Vr1.
The deceleration section includes a deceleration section in which the carriage 41 decelerates and stops toward the target stopping point, starting immediately after the carriage 41 reaches the deceleration start point.

In the next step S260, the processor 11 sets a set of threshold values Th for the operation amount U for jam detection corresponding to the speed profile set in S250 for the jam detector 140. That is, the processor 11 sets a threshold value Th1 in the acceleration section, a threshold value Th2 in the constant speed section, and a threshold value Th6 in the deceleration section. The threshold values Th1 and Th2 in the acceleration section and the constant speed section may be the same values as the threshold values Th1 and Th2 corresponding to the first speed profile.

In this way, the processor 11 sets the speed profile and the threshold set Th in S130, and performs main scanning direction printing (S140) based on the set speed profile. When the carriage 41 moves during this main scanning direction printing, the jam detector 140 repeatedly executes the jam detection process shown in FIG. 8.

In the jam detection process, the jam detector 140 selects a threshold Thx from the threshold group Th according to the current movement section of the carriage 41 (S310). The movement section is determined based on the elapsed time since the start of control based on the speed profile.

The jam detector 140 sets a threshold value Th1 when the carriage 41 is in the acceleration section, and sets a threshold value Th2 when the carriage 41 is in the first constant speed section. Similarly, the jam detector 140 sets corresponding threshold values Th3, Th4, and Th5 when the carriage 41 is in the re-acceleration section, the second constant speed section, and the deceleration section, respectively.

The jam detector 140 further selects a threshold value corresponding to the current movement section of the carriage 41 as the threshold value Tex for the deviation E (S320, S330, S335). The jam detector 140 determines whether the movement section of the carriage 41 is a constant speed section (S320). When the speed profile is the first speed profile, the constant speed sections are the first constant speed section and the second constant speed section.

When the jam detector 140 determines that the section in which the carriage 41 moves is a constant speed section (Yes in S320), it selects a predetermined first threshold Te1 as the threshold Tex (S330).

When the jam detector 140 determines that the section of movement of the carriage 41 is a non-constant speed section (No in S320), it selects a second threshold Te2, which is greater than a predetermined first threshold Te1, as the threshold Tex (S335).

The first threshold Te1 and the second threshold Te2, which correspond to the constant speed section and the non-constant speed section, respectively, may be determined in advance by a designer and stored in the ROM 12 or the EEPROM 15. The first threshold Te1 and the second threshold Te2 may be updated based on the fluctuation range of the deviation E obtained by moving the carriage 41 when the image forming system 1 is started up and it is estimated that no paper P is present.

After selecting the threshold value Tex, the jam detector 140 determines whether the absolute value of the deviation E calculated by the speed controller 130 is greater than the threshold value Tex (S340). If it is determined that the absolute value of the deviation E is equal to or less than the threshold value Tex (No in S340), the jam detector 140 determines that no jam has occurred and ends the jam detection process.

On the other hand, if it is determined that the absolute value of the deviation E is greater than the threshold value Tex (Yes in S340), the jam detector 140 determines whether the current movement section of the carriage 41 is a non-constant speed section (S350). The non-constant speed section corresponds to the acceleration section, the deceleration section, and the re-acceleration section.

If it is determined that the section of movement of the carriage 41 is a constant speed section and not a non-constant speed section (No in S350), the jam detector 140 detects that a jam has occurred and notifies the processor 11 of the occurrence of the jam (S370).

In addition, if the jam detector 140 determines that the section of movement of the carriage 41 is a non-constant speed section (Yes in S350), it determines whether the operation amount U output from the speed controller 130 is greater than the threshold value Thx (S360). If it determines that the operation amount U is equal to or less than the threshold value Thx (No in S360), the jam detector 140 determines that no jam has occurred and ends the jam detection process.

If it is determined that the operation amount U is greater than the threshold value Thx (Yes in S360), the jam detector 140 detects that a jam has occurred and notifies the processor 11 of the occurrence of the jam (S370). Then, the jam detection process ends.

In this way, in the constant speed section, the jam detector 140 detects a jam based only on the deviation E out of the deviation E and the operation amount U, and in the non-constant speed section, the jam detector 140 detects a jam based on both the deviation E and the operation amount U.

As another example, the jam detector 140 may not execute the process of S350. That is, the process of S360 may be executed not only when the carriage 41 is in a non-constant speed section, but also when it is in a constant speed section. In this case, the jam detector 140 detects a jam based on both the deviation E and the operation amount U in both the constant speed section and the non-constant speed section. In an example in which the process of S350 is executed, the threshold values Th2 and Th4 for the first constant speed section and the second constant speed section are not actually used, and therefore do not need to be set.

Next, the details of the jam-related processing that the processor 11 executes based on a notification of a jam occurrence will be described with reference to FIG. 9. The processor 11 executes the jam-related processing shown in FIG. 9 when it starts controlling the movement of the carriage 41.

When jam-related processing is started, the processor 11 waits until it receives notification that a jam has occurred, and when it receives notification that a jam has occurred (Yes in S410), it commands the CR motor control unit 31 to execute specific control to deal with the jam (S420).

According to a first example, the specific control may be to control the CR motor 51 so as to decelerate the carriage 41. According to a second example, the specific control may be to control to stop the CR motor 51. According to a third example, the specific control may be to control to rotate the CR motor 51 in the reverse direction and to move the carriage 41 backward a predetermined distance from the current position.

After executing the process of S420, the processor 11 displays an error message and outputs an error notification sound via the user interface 17 to notify the user of the occurrence of a jam (S430). Then, the jam-related process ends.

According to the image forming system 1 of this embodiment described above, when the carriage 41 accelerates or decelerates, a jam is detected not only based on a comparison between the deviation E and the threshold value Tex, but also based on a comparison between the operation amount U and the threshold value Thx, so that a jam can be detected appropriately.

When a jam occurs, the deviation E becomes large, but the deviation E also tends to become large when the carriage 41 is accelerating or decelerating due to a delay in the tracking of the actual speed relative to the target speed Vr. In other words, when accelerating or decelerating, if a jam is detected based only on the deviation E, there is a high possibility that a jam will be erroneously detected even in a situation where a jam has not occurred due to a delay in tracking the actual speed.

On the other hand, if the threshold Tex is set too high in order to prevent false positives, a jam may not be detected even though it has occurred, or it may take a long time to detect. In other words, if the threshold Tex is set too high, false positives will be prevented, but the detection sensitivity will deteriorate.

In contrast, in this embodiment, when accelerating or decelerating, the occurrence of a jam is detected if both of the two conditions related to the deviation E and the operation amount U are satisfied, so that jams can be detected with high accuracy and sensitivity.

According to this embodiment, as the carriage 41 moves at high speed, particularly in non-ink ejection sections, the carriage 41 is accelerated and decelerated more frequently in locations where a jam may occur. In an image forming system 1 involving such acceleration and deceleration, by adopting the jam detection method described above, it is possible to configure the image forming system 1 to be able to properly detect paper jams while improving the throughput of the printing process.

[First Modification]
Next, a first modified image forming system 1 will be described. The first modified image forming system 1 is basically the same as the main embodiment described above, except for the jam detection process executed by the jam detector 140. Therefore, in the following, a description other than the jam detection process will be omitted.

According to the first modified example, the jam detector 140 repeatedly executes the jam detection process shown in FIG. 10. When the jam detection process of the first modified example is started, the jam detector 140 selects a threshold value Thx corresponding to the current movement section of the carriage 41 from the set threshold value group Th (S510), similar to the process in S310.

Then, the jam detector 140 judges whether the operation amount U output from the speed controller 130 is greater than the threshold value Thx (S520). If it is judged that the operation amount U is equal to or less than the threshold value Thx (No in S520), the jam detector 140 determines that a jam has not occurred and ends the jam detection process.

If it is determined that the operation amount U is greater than the threshold value Thx (Yes in S520), the jam detector 140 detects that a jam has occurred and notifies the processor 11 of the occurrence of the jam (S530). Then, the jam detection process ends.

In this way, the jam detector 140 of the first modified example detects the occurrence of a jam not based on the deviation E, but based on a comparison between the thresholds Th1-Th6 set for each section and the operation amount U. Therefore, according to the first modified example, it is possible to appropriately detect a jam by suppressing erroneous detection caused by a delay in tracking the actual speed, which occurs when detecting the occurrence of a jam based on the deviation E.

[Second Modification]
Next, a second modified image forming system 1 will be described. The second modified image forming system 1 is basically the same as the main embodiment described above, except for the jam detection process executed by the jam detector 140. Therefore, in the following, a description of the process other than the jam detection process will be omitted.

According to the second modified example, the jam detector 140 repeatedly executes the jam detection process shown in FIG. 11. When the jam detection process of the second modified example is started, the jam detector 140 determines whether the current movement section of the carriage 41 is a constant speed section (S610), similar to the process in S320.

When the jam detector 140 determines that the section in which the carriage 41 moves is a constant speed section (Yes in S610), it selects a predetermined first threshold Te1 as the threshold Tex (S620), similar to the processing in S330.

When the jam detector 140 determines that the section of movement of the carriage 41 is a non-constant speed section (No in S610), it selects a second threshold Te2, which is greater than a first threshold Te1 that has been determined in advance, as the threshold Tex (S625), similar to the processing in S335.

After selecting the threshold value Tex, the jam detector 140 determines whether the absolute value of the deviation E calculated by the speed controller 130 is greater than the threshold value Tex (S630). If it is determined that the absolute value of the deviation E is equal to or less than the threshold value Tex (No in S630), the jam detector 140 determines that no jam has occurred and ends the jam detection process.

On the other hand, if it is determined that the absolute value of the deviation E is greater than the threshold value Tex (Yes in S630), the jam detector 140 detects that a jam has occurred and notifies the processor 11 of the occurrence of the jam (S640). Then, the jam detection process ends.

In this way, the jam detector 140 of the second modified example detects the occurrence of a jam not based on the operation amount U, but based on a comparison of the deviation E with the thresholds Te1 and Te2, which vary for each section. As described above, the deviation E tends to be large, especially in the acceleration/deceleration section, due to a delay in the actual speed following the target speed Vr. This can cause an increase in the rate of false jam detection. However, according to the second modified example, the threshold Tex is set larger in the acceleration/deceleration section than in the constant speed section, so that jams can be detected with higher accuracy and with a lower rate of false detection than with a method of setting a uniform threshold across the entire section.

[Third Modification]
Next, a third modified image forming system 1 will be described. The third modified image forming system 1 is basically the same as the main embodiment described above, except for the jam detection process executed by the jam detector 140. Therefore, in the following, a description other than the jam detection process will be omitted.

According to the third modified example, the jam detector 140 repeatedly executes the jam detection process shown in FIG. 12. When the jam detection process of the third modified example is started, the jam detector 140 executes the processes of S310 to S335, similar to the jam detection process shown in FIG. 8, and sets the threshold values Thx and Tex according to the movement section of the carriage 41.

Then, the jam detector 140 determines whether the absolute value of the deviation E calculated by the speed controller 130 is greater than the threshold value Tex (S740). If it is determined that the absolute value of the deviation E is greater than the threshold value Tex (Yes in S740), the jam detector 140 detects that a jam has occurred and notifies the processor 11 of the occurrence of the jam (S770).

On the other hand, if the jam detector 140 determines that the absolute value of the deviation E is equal to or less than the threshold value Tex (No in S740), it determines whether the manipulated variable U output from the speed controller 130 is greater than the threshold value Thx (S750). If it determines that the manipulated variable U is equal to or less than the threshold value Thx (No in S750), the jam detector 140 determines that no jam has occurred and ends the jam detection process.

On the other hand, if it is determined that the operation amount U is greater than the threshold value Thx (Yes in S750), the jam detector 140 detects that a jam has occurred and notifies the processor 11 of the occurrence of the jam (S770). Then, the jam detection process ends.

In this way, the jam detector 140 of the third modified example detects the occurrence of a jam on the condition that either the operation amount U exceeds the threshold value Thx or the deviation E exceeds the threshold value Tex. According to this example, because jam detection is performed based on the operation amount U, increasing the threshold value Tex for jam detection based on the deviation E does not reduce the detection sensitivity to jams. Therefore, according to the third modified example, it is possible to detect a jam more appropriately than when the occurrence of a jam is detected based only on the deviation E.

[Fourth Modification]
Next, the image forming system 1 of the fourth modified example will be described. The image forming system 1 of the fourth modified example differs from the main embodiment in that it is configured to detect an inhibition area on the encoder 55 and switch the jam detection method based on the inhibition area. The other configurations of the image forming system 1 of the fourth modified example are the same as those of the main embodiment. Therefore, the following mainly describes the inhibition area and the jam detection process, and other descriptions are omitted.

When measuring the position and speed of the carriage 41 using the encoder 55, if dirt 56 is present in a portion of the encoder scale 55A, accurate measurement may not be possible.

In the encoder 55, an optical sensor 55B fixed to the carriage 41 moves in the main scanning direction along the encoder scale 55A in conjunction with the carriage 41. This movement causes the optical sensor 55B to move relative to the encoder scale 55A in the main scanning direction, reads a slit 55C provided in the encoder scale 55A, and outputs a pulse signal corresponding to the movement in the main scanning direction as an encoder signal. The slit 55C can be made of, for example, a transparent member.

If stains 56 such as ink stains are present on the encoder scale 55A, the optical sensor 55B cannot read the slits 55C of the encoder scale 55A. Therefore, if stains 56 are present on the encoder scale 55A, the pulse edge interval of the encoder signal changes, causing a large measurement error in the velocity V of the carriage 41, which is measured based on the pulse edge interval.

The lower part of Figure 13 shows an example of an encoder signal output from optical sensor 55B when optical sensor 55B passes at a constant speed over the dirty encoder scale 55A shown in the upper part of Figure 13. According to this example, the pulse edge interval of the encoder signal, which should be equal under normal circumstances, increases threefold when optical sensor 55B passes over dirt 56.

In this way, the area where the dirt 56 is attached is an area where normal reading of the encoder scale 55A and normal measurement of the speed V are hindered. The above-mentioned "hindered area" refers to the movement range of the carriage 41 where the optical sensor 55B reads the area where the dirt 56 is attached as an obstruction to the encoder scale 55A.

When the carriage 41 passes through the inhibition area, the pulse edge interval changes significantly, and the deviation E calculated based on the speed V, which includes a large measurement error, may exceed the threshold value Tex even when a jam has not occurred. For this reason, in the fourth modified example, the jam detector 140 executes the jam detection process shown in FIG. 14. This jam detection process is executed repeatedly by the jam detector 140.

When the jam detection process starts, the jam detector 140 determines whether the carriage 41 is in the obstruction area (S810). The position of the obstruction area is identified, for example, by a pre-scan that is performed beforehand when the image forming system 1 is started, and is stored in the RAM 13 as position information. In the pre-scan, the carriage 41 is controlled to move at a constant speed from one end of the movable range of the carriage 41 to the other end, and the obstruction area is detected from the output of the encoder signal at that time.

The jam detector 140 can determine whether the carriage 41 is in the obstruction area by comparing the position X of the carriage 41 measured by the signal processing circuit 110 with the position information of the obstruction area.

If it is determined that the carriage 41 is not in the obstruction area (No in S810), the jam detector 140 executes a first detection process (S820) that is the same as the jam detection process shown in FIG. 8. On the other hand, if it is determined that the carriage 41 is in the obstruction area (Yes in S810), the jam detector 140 executes a second detection process (S830) that is the same as the jam detection process shown in FIG. 10.

As a result, when the carriage 41 is in the inhibition area, the jam detector 140 detects a jam based on the operation amount U without using the deviation E. As another example, in S820, the jam detector 140 may execute the jam detection process shown in FIG. 11 or 12 as the first detection process.

According to the fourth modified example, the occurrence of a jam can be detected from the manipulated variable U without being affected by the measurement error of the speed V caused by the dirt 56 on the encoder scale 55A. Therefore, it is possible to suppress erroneous detection of a jam caused by the dirt 56.

Although exemplary embodiments of the present disclosure, including modified examples, have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take various forms. The technology of the present disclosure can be applied not only to the image forming system 1 that forms an image on paper P, but also to various systems in which the movement of a processing head that performs a specified processing on an object is realized by motor control using an encoder.

For example, the technology disclosed herein can be applied not only to inkjet printers, but also to other serial printers and garment printers. The technology disclosed herein can be applied to various systems in which jams may occur due to contact between a moving body and a sheet.

The technology disclosed herein may be applied to a system that controls a motor by controlling the drive current, in addition to a system that controls a motor by controlling the drive voltage. That is, the manipulated variable U may be a current command value instead of a voltage command value. The manipulated variable U may also be a PWM value.

The functions of one component in the above embodiment may be distributed among multiple components. The functions of multiple components may be integrated into one component. For example, the controller does not have to be configured with a processor 11 and an ASIC 20, but may be configured with one or more processors without an ASIC, may be configured with one or more ASICs without a processor, or may be configured with a combination of one or more processors and one or more ASICs. One or more components of the controller including at least one of a processor and an ASIC can cooperate with each other to execute processing related to the controller of the present disclosure.

In addition, some of the configurations of the embodiments may be omitted. Any aspect included in the technical idea specified by the wording of the claims is an embodiment of the present disclosure.

1...Image forming system, 11...Processor, 12...ROM, 13...RAM, 15...EEPROM, 17...User interface, 19...Communication interface, 20...ASIC, 21...Recording control unit, 22...Recording head, 23...Drive circuit, 31...CR motor control unit, 35...LF motor control unit, 40...Carriage transport mechanism, 41...Carriage, 42...Guide rail, 43...Belt mechanism, 51...CR motor, 53...Drive circuit, 55...Encoder, 5 5A...encoder scale, 55B...optical sensor, 55C...slit, 60...paper transport mechanism, 61...roller, 71...LF motor, 73...drive circuit, 75...encoder, 110...signal processing circuit, 120...command generator, 130...speed controller, 140...jam detector, 210...subtractor, 220...gain amplifier, 230, 240, 250...adder, 290...disturbance observer, 431...drive pulley, 433...driven pulley, 435...belt, P...paper.

Claims (13)

A motor;
a movable body configured to be driven by the motor and to reciprocate in a first direction, the movable body configured to process a sheet conveyed in a second direction intersecting the first direction so as to cross a movement path of the movable body;
A measuring device configured to measure the speed of the moving object;
a controller configured to control the motor based on a speed profile;
Equipped with
The controller:
calculating an operation amount for the motor based on a deviation between a target speed of the moving body according to the speed profile and the speed measured by the measuring device, and controlling the motor by supplying power according to the operation amount to the motor so that the moving body reciprocates according to the target speed;
detecting an occurrence of an event in which the movable body comes into contact with the seat, on condition that both of the operation amount exceeding a first threshold value set in advance and the deviation exceeding a second threshold value set in advance are satisfied;
A control system that executes the above. A motor;
a movable body configured to be driven by the motor and to reciprocate in a first direction, the movable body configured to process a sheet conveyed in a second direction intersecting the first direction so as to cross a movement path of the movable body;
A measuring device configured to measure the speed of the moving object;
a controller configured to control the motor based on a speed profile;
Equipped with
The controller:
calculating an operation amount for the motor based on a deviation between a target speed of the moving body according to the speed profile and the speed measured by the measuring device, and controlling the motor by supplying power according to the operation amount to the motor so that the moving body reciprocates according to the target speed;
detecting an occurrence of an event in which the movable body comes into contact with the seat, on a condition that one of the operation amount exceeding a first threshold value set in advance and the deviation exceeding a second threshold value set in advance is satisfied;
A control system that executes the above. A motor;
a movable body configured to be driven by the motor and to reciprocate in a first direction, the movable body configured to process a sheet conveyed in a second direction intersecting the first direction so as to cross a movement path of the movable body;
A measuring device configured to measure the speed of the moving object;
a controller configured to control the motor based on a speed profile;
Equipped with
the speed profile defines target speeds in a plurality of sections including an acceleration section in which the moving body accelerates, a constant speed section in which the moving body moves at a constant speed, and a deceleration section in which the moving body decelerates;
The controller:
calculating an operation amount for the motor based on a deviation between a target speed of the moving body according to the speed profile and the speed measured by the measuring device, and controlling the motor by supplying power according to the operation amount to the motor so that the moving body reciprocates according to the target speed;
detecting an occurrence of an event in which the movable body comes into contact with the sheet on condition that the amount of operation exceeds a preset first threshold in each of the acceleration section and the deceleration section , and detecting the occurrence of the event on condition that the deviation exceeds a preset second threshold in the constant speed section;
A control system that executes the above. 4. The control system according to claim 3, wherein the controller detects the occurrence of the event on the condition that both of the following conditions are satisfied in each of the acceleration section and the deceleration section: the manipulated variable exceeds the first threshold value, and the deviation exceeds the second threshold value. an encoder including an encoder scale and a sensor configured to move relative to the encoder scale in conjunction with the movable body and to output an encoder signal based on reading of the encoder scale;
The measuring instrument measures the speed based on the encoder signal,
The control system according to claim 3 or claim 4, wherein the controller detects the occurrence of the event on the condition that the manipulated variable exceeds the first threshold value, regardless of the deviation, when the moving body passes through an obstruction area, which is the movement area of the moving body read by the sensor, where an obstruction object is attached to a portion of the encoder scale that obstructs normal reading of the encoder scale by the sensor. the speed profile defines the target speed in a plurality of sections in which at least one of a height and a change in the target speed is different;
an individual threshold is set as the first threshold for each of at least two or more sections among the plurality of sections;
3. The control system according to claim 1 , wherein the controller detects the occurrence of the event in each of the two or more sections by using a threshold value set individually for the corresponding section as the first threshold value in each of the two or more sections. the plurality of sections include an acceleration section in which the moving body accelerates, a constant speed section in which the moving body moves at a constant speed, and a deceleration section in which the moving body decelerates,
an individual threshold is set as the first threshold for at least the acceleration section and the deceleration section among the plurality of sections,
The control system according to claim 6 , wherein the controller detects the occurrence of the event in each of the acceleration section and the deceleration section by using a threshold value set individually for the corresponding section as the first threshold value . an individual threshold is set as the first threshold for at least the acceleration section and the deceleration section among the plurality of sections,
The control system according to any one of claims 3 to 5, wherein the controller detects the occurrence of the event in each of the acceleration section and the deceleration section by using a threshold value that is individually set for the corresponding section as the first threshold value . the plurality of sections include an acceleration section in which the moving body transitions from a stopped state to a constant speed state, a deceleration section in which the moving body transitions from a constant speed state to a stopped state, and an intermediate section between the acceleration section and the deceleration section,
the intermediate section includes a first constant speed section in which the moving body moves at a first constant speed, a second constant speed section in which the moving body moves at a second constant speed higher than the first speed, and a non-constant speed section in which the moving body moves at a non-constant speed,
an individual threshold is set as the first threshold for at least the acceleration section, the deceleration section, and the non-constant speed section among the plurality of sections;
The control system according to claim 6, wherein the controller detects the occurrence of the event by using a threshold value set individually for each of the acceleration section, the deceleration section, and the non-constant speed section as the first threshold value in each of the acceleration section, the deceleration section, and the non - constant speed section. the plurality of sections include the acceleration section during which the moving body transitions from a stopped state to a constant speed state, the deceleration section during which the moving body transitions from a constant speed state to a stopped state, and an intermediate section between the acceleration section and the deceleration section,
the intermediate section includes, as the constant speed section, a first constant speed section in which the moving body moves at a first constant speed, and a second constant speed section in which the moving body moves at a second constant speed higher than the first speed , and further includes a non-constant speed section in which the moving body moves at a non-constant speed,
an individual threshold is set as the first threshold for at least the acceleration section, the deceleration section, and the non-constant speed section among the plurality of sections;
The control system according to claim 8, wherein the controller detects the occurrence of the event by using a threshold value set individually for each of the acceleration section, the deceleration section, and the non-constant speed section as the first threshold value in each of the acceleration section, the deceleration section, and the non - constant speed section. The control system according to any one of claims 1 to 10 , wherein the controller controls the motor to stop the motor when the controller detects the occurrence of the event. The control system according to any one of claims 1 to 10 , wherein the controller controls the motor so that the moving body moves backward when the controller detects the occurrence of the event. The control system according to any one of claims 1 to 10 , wherein the controller controls the motor so as to decelerate the moving body when the controller detects the occurrence of the event.

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