JP2022102213A - Printer and management method - Google Patents

Abstract

To provide a technique which can specify a measurement spot where the influence degree to a positional deviation of ink is high among a plurality of measurement spots in a printer.SOLUTION: A control unit 50 of a printer comprises: a detection unit 51; a calculation unit 52; and a specification unit 53. The detection unit 51 detects a positional deviation amount R of ink discharged to a surface of a base material from a plurality of heads on the basis of the photographed image I obtained from a camera 40. The calculation unit 52 acquires measurement values S1, S2, S3... from a plurality of sensors 30 and acquires the positional deviation amount R from the detection unit 51. The calculation unit 52 calculates impact values V1, V2, V3 indicating an influence degree at which the measurement values S1, S2, S3... affect the positional deviation amount for each measurement spot. The specification unit 53 specifies the measurement spot where the influence degree to the positional deviation amount R is high among the plurality of measurement spots on the basis of the plurality of impact values V1, V2, V3.SELECTED DRAWING: Figure 4

Description

The present invention relates to a printing technique for ejecting ink from a plurality of heads to the surface of a substrate while conveying a long strip-shaped substrate in the longitudinal direction along a predetermined transport path.

Conventionally, an inkjet printing device that prints an image on a base material by ejecting ink from a plurality of heads while transporting a long strip-shaped base material in the longitudinal direction is known. The inkjet printing device ejects inks of different colors from a plurality of heads. Then, a multicolor image is printed on the surface of the base material by superimposing the monochromatic images formed by the inks of each color. A conventional printing apparatus is described in, for example, Patent Document 1.

JP-A-2018-16412

In this type of printing apparatus, a slight misalignment (so-called “misregistration”) may occur between the plurality of monochromatic images described above. Misregistration occurs due to various factors such as rotation error of the roller that conveys the base material, torque of the motor, expansion and contraction of the base material, and vertical displacement of the base material. For this reason, it was extremely difficult to identify the location that causes the misregistration.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique capable of identifying a measurement point having a high degree of influence on ink misalignment among a plurality of measurement points in a printing apparatus. ..

In order to solve the above problems, the first invention of the present application is a transport mechanism for transporting a long strip-shaped base material in the longitudinal direction along a predetermined transport path, and ink on the surface of the base material transported by the transport mechanism. A plurality of heads for discharging, a plurality of sensors for measuring the state of a plurality of measurement points in the apparatus, a camera for photographing the surface of the base material on the downstream side of the transport path from the plurality of heads, and the above The control unit includes a plurality of sensors and a control unit communicably connected to the camera, and the control unit includes ink ejected from the plurality of heads to the surface of the base material based on a captured image obtained from the camera. The detection unit that detects the mutual misalignment amount and the plurality of sensors acquire the measured value, and the misaligned amount is acquired from the detection unit, and the degree of influence of the measured value on the misaligned amount is determined. A calculation unit that calculates the indicated impact value for each measurement location, and a specific unit that identifies a measurement location that has a high degree of influence on the displacement amount among the plurality of measurement locations based on the plurality of impact values. , Have.

The second invention of the present invention is the printing apparatus of the first invention, in which the calculation unit calculates the impact value as time-series data for each measurement location, and the specific unit changes the impact value over time. Based on the above, a measurement point having a high degree of influence on the amount of misalignment is specified.

The third invention of the present application is the printing apparatus of the first invention or the second invention, and the calculation unit uses a plurality of the measured values and the misalignment amount as observation variables by a statistical causal search program. The impact value is calculated based on the strength of the causal relationship between the observed variables and the estimation of the causal relationship between the observed variables.

The fourth invention of the present application is the printing apparatus of the third invention, and the statistical causal search program is a LiNGAM program.

The fifth invention of the present application is the printing apparatus of the third invention or the fourth invention, and the calculation unit selects a causal relationship having an intensity equal to or higher than a threshold value among a plurality of causal relationships among a plurality of the observed variables. Then, the impact value is calculated based on the strength of the selected causal relationship.

The sixth invention of the present application is the printing apparatus of any one of the first to fifth inventions, and the control unit further includes an output unit that outputs information of a measurement point specified by the specific unit. Have.

The seventh invention of the present application is the printing apparatus of any one of the first to sixth inventions, and the control unit reduces the amount of misalignment at the measurement point specified by the specific unit. It further has an adjusting unit for adjusting so as to.

The eighth invention of the present application is a management method of a printing apparatus that ejects ink from a plurality of heads to the surface of a substrate while conveying a long strip-shaped substrate in the longitudinal direction along a predetermined transport path. a) a step of measuring the state of a plurality of measurement points in the printing apparatus, b) a step of detecting the amount of mutual misalignment of ink ejected from the plurality of heads onto the surface of the substrate, and c) the above. A step of calculating an impact value indicating the degree of influence of the measured value acquired in the step a) on the amount of misalignment detected in the step b) for each measurement point, and d) a plurality of the impact values. Based on the above, the present invention includes a step of specifying a measurement point having a high degree of influence on the amount of misalignment among the plurality of measurement points.

The ninth invention of the present application is the management method of the eighth invention, in which the impact value is calculated as time-series data for each measurement point in the step c), and the impact value is calculated in the step d). Based on the change over time, a measurement point having a high degree of influence on the amount of misalignment is specified.

The tenth invention of the present application is the management method of the eighth invention or the ninth invention, and in the step c), a plurality of the measured values and the misalignment amount are used as observation variables by a statistical causal search program. , The causal relationship between the observed variables is estimated, and the impact value is calculated based on the strength of the causal relationship between the observed variables.

The eleventh invention of the present application is the management method of the tenth invention, and the statistical causal search program is a LiNGAM program.

The twelfth invention of the present application is the management method of the tenth invention or the eleventh invention, and the step c) is c1) a causal relationship in which the intensity is equal to or higher than the threshold value among a plurality of causal relationships among the plurality of observed variables. It has a step of selecting a relationship and a step of calculating the impact value based on the strength of the causal relationship selected in c2) the step c1).

The thirteenth invention of the present application is a management method of any one of the eighth to twelfth inventions, and further includes a step of outputting information of a measurement point specified by e) the step d).

The 14th invention of the present application is the management method of any one of the 8th to 13th inventions, and f) the measurement point specified by the step d) is set so that the amount of misalignment is small. It also has a step of adjustment.

According to the first to fourteenth inventions of the present application, an impact value indicating the degree of influence of the measured value on the amount of ink misalignment is calculated for each measurement point of the sensor. This makes it possible to identify the measurement points having a high degree of influence on the ink misalignment among the plurality of measurement points in the printing apparatus.

In particular, according to the fifth and twelfth inventions of the present application, the impact value can be calculated while eliminating noise and reducing the calculation load by selecting only the intensity equal to or higher than the threshold value.

In particular, according to the sixth and thirteenth inventions of the present application, the user of the printing apparatus can grasp the measurement points affecting the position shift of the ink by checking the output information.

In particular, according to the seventh invention and the fourteenth invention of the present application, the influence of each measurement point on the position shift of the ink can be suppressed.

It is a figure which showed the structure of a printing apparatus. It is a partial top view of the printing apparatus in the vicinity of a printing part. It is a block diagram which showed the connection between a control part and each part of a printing apparatus. It is a block diagram which conceptually showed the function of a control part. This is an example of a chart showing the causal relationship between the observed variables estimated by the statistical causal search program. This is an example of a chart in which only arrows above the threshold are selected. It is a graph which shows an example of the time-dependent change of an impact value.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1. Printing device configuration>
FIG. 1 is a diagram showing a configuration of a printing apparatus 1 according to an embodiment of the present invention. The printing apparatus 1 prints an image on the surface of the base material 9 by ejecting ink droplets from a plurality of heads 21 to 24 toward the base material 9 while transporting the long strip-shaped base material 9. It is a device to print. The base material 9 may be printing paper or a resin film. Further, the base material 9 may be a metal foil or a base material made of glass. As shown in FIG. 1, the printing device 1 includes a transport mechanism 10, a printing unit 20, a plurality of sensors 30, a camera 40, and a control unit 50.

The transport mechanism 10 is a mechanism for transporting the base material 9 in the transport direction along the longitudinal direction thereof. The transport mechanism 10 of the present embodiment has a winding section 11, a plurality of transport rollers 12, and a winding section 13. The base material 9 is unwound from the unwinding portion 11 and is conveyed along a transfer path composed of a plurality of transfer rollers 12. Each transport roller 12 guides the base material 9 to the downstream side of the transport path by rotating around an axis extending in a direction perpendicular to the transport direction. The base material 9 is hung on a plurality of transfer rollers 12 in a state where tension is applied. As a result, slackening and wrinkling of the base material 9 during transportation are suppressed. The base material 9 after transportation is collected by the winding unit 13.

The printing unit 20 is a processing unit that ejects ink droplets (hereinafter referred to as “ink droplets”) to the base material 9 conveyed by the conveying mechanism 10. The printing unit 20 of the present embodiment has a first head 21, a second head 22, a third head 23, and a fourth head 24. The first head 21, the second head 22, the third head 23, and the fourth head 24 are arranged at intervals along the transport direction of the base material 9. The base material 9 is conveyed below the four heads 21 to 24 with the printed surface facing upward.

FIG. 2 is a partial top view of the printing apparatus 1 in the vicinity of the printing unit 20. As shown by the broken line in FIG. 2, a plurality of nozzles 201 arranged in parallel with the width direction of the base material 9 are provided on the lower surface of each head 21 to 24. Each of the heads 21 to 24 is directed from the plurality of nozzles 201 toward the upper surface of the base material 9, and each color of C (cyan), M (magenta), Y (yellow), and K (black), which are the color components of the multicolor image. Ink droplets are ejected respectively.

That is, the first head 21 ejects C-color ink droplets on the upper surface of the base material 9 at the first printing position P1 on the transport path. The second head 22 ejects M-color ink droplets on the upper surface of the base material 9 at the second printing position P2 on the downstream side of the first printing position P1. The third head 23 ejects Y-color ink droplets on the upper surface of the base material 9 at the third printing position P3 on the downstream side of the second printing position P2. The fourth head 24 ejects K-color ink droplets on the upper surface of the base material 9 at the fourth printing position P4 on the downstream side of the third printing position P3.

A drying processing unit for drying the ink discharged on the printed surface of the base material 9 may be further provided on the downstream side of the heads 21 to 24 in the transport direction. The drying processing unit dries the ink by, for example, spraying a heated gas toward the base material 9 to vaporize the solvent in the ink adhering to the base material 9. However, the drying processing unit may be one that cures or dries the ink by another method such as light irradiation.

The plurality of sensors 30 are measuring instruments that measure the state of the device. The plurality of sensors 30 acquire measured values at a plurality of measurement points in the printing apparatus 1. The measurement items of the sensor 30 include, for example, the rotational speed of the motor that operates the transfer mechanism 10, the torque of the motor, the rotational speed of some of the transfer rollers 12, the tension of the base material 9, and the vertical displacement of the base material 9 (base). The amount of displacement in the direction perpendicular to the material 9), the position in the width direction of the edge of the base material 9, and the like can be included. The sensors 30 for measuring the same item may be arranged at a plurality of positions on the transport path. The plurality of sensors 30 measure the state of each measurement point, and output a signal indicating the obtained measured value to the control unit 50.

The camera 40 is an image pickup device that photographs the upper surface of the base material 9 that has passed through the printing unit 20. The camera 40 is arranged to face the printing surface of the base material 9 at the photographing position P5 on the downstream side of the transport path from the printing unit 20. For the camera 40, for example, a line sensor in which a plurality of image pickup elements such as CCD and CMOS are arranged in the width direction is used. The camera 40 acquires the printed image data of the base material 9 by photographing the printed surface of the base material 9. Then, the camera 40 transmits the obtained image data to the control unit 50.

The control unit 50 is an information processing device for controlling the operation of each unit of the printing device 1. FIG. 3 is a block diagram showing the connection between the control unit 50 and each unit of the printing device 1. As conceptually shown in FIG. 3, the control unit 50 is composed of a computer having a processor 501 such as a CPU, a memory 502 such as RAM, and a storage unit 503 such as a hard disk drive. A computer program 80 for executing a printing process is stored in the storage unit 503.

Further, as shown in FIG. 3, the control unit 50 is communicably connected to the above-mentioned transport mechanism 10, the four heads 21 to 24, the plurality of sensors 30, and the camera 40, respectively. The control unit 50 controls the operation of each of these units according to the computer program 80 and various data. As a result, the printing process for the base material 9 proceeds.

<2. About device status management function>
In this printing apparatus 1, the four heads 21 to 24 print a monochrome image on the upper surface of the base material 9 by ejecting ink droplets. Then, a multicolor image is formed on the upper surface of the base material 9 by superimposing the four monochromatic images. Therefore, if the positions of the ink droplets ejected from the four heads 21 to 24 on the base material 9 are deviated from each other, the image quality of the printed matter is deteriorated.

The control unit 50 has a function for grasping the cause of such misalignment of ink droplets on the base material 9 and managing the state of the printing apparatus 1. FIG. 4 is a block diagram conceptually showing the function of the control unit 50. As shown in FIG. 4, the control unit 50 includes a detection unit 51, a calculation unit 52, a specific unit 53, an output unit 54, and an adjustment unit 55. The functions of the detection unit 51, the calculation unit 52, the specific unit 53, the output unit 54, and the adjustment unit 55 are realized by the processor 501 of the control unit 50 operating according to the computer program 80.

When the printing device 1 is in operation, the plurality of sensors 30 described above constantly measure the state of each measurement point in the device. Further, when the printing apparatus 1 is in operation, the above-mentioned camera 40 always photographs the upper surface of the base material 9 after printing. The control unit 50 acquires the measured values S1, S2, S3, ... From the plurality of sensors 30, and also acquires the captured image I from the camera 40. Then, based on these measured values S1, S2, S3, ... And the captured image I, the detection unit 51, the calculation unit 52, the specific unit 53, the output unit 54, and the adjustment unit 55 are operated.

Based on the captured image I obtained from the camera 40, the detection unit 51 refers to the amount of mutual misalignment of the ink droplets ejected from the four heads 21 to 24 on the upper surface of the base material 9 (hereinafter referred to as “register misalignment amount R”). ) Is detected. The detection unit 51 color-separates the captured image I transmitted from the camera 40 into four monochromatic images C, M, Y, and K. Then, the detection unit 51 detects the mutual positional deviation amount of the four monochromatic images as the above-mentioned misregistration amount R. For example, the detection unit 51 uses the position relative to each of the M color, Y color, and K color ink droplets as the misregistration amount R with respect to the position of the C color ink droplet.

The calculation unit 52 acquires the measured values S1, S2, S3, ... From the plurality of sensors 30, and also acquires the misregistration amount R from the detection unit 51. The calculation unit 52 acquires a plurality of types of measured values S1, S2, S3, ... And a misregistration amount R, respectively, as time-series data that changes with time.

As shown in FIG. 4, the calculation unit 52 has a statistical causal search program 81. The statistical causal search program 81 is stored in the storage unit 503 as a part of the computer program 80 described above. The statistical causal search program 81 is a program for inferring a causal relationship between a plurality of observed variables. The calculation unit 52 uses, for example, a LiNGAM (Linear Non-Gaussian Acyclic Model) program as the statistical causal search program 81. The LiNGAM program is based on a model that assumes that the relationship between multiple observed variables and the unobserved coefficients (error variables) that affect each observed variable is linear, and that the unobserved variables are independent of each other and follow a non-Gaussian continuous distribution. Based on this, it is a program that infers the causal relationship between observed variables.

The calculation unit 52 executes the statistical causal search program 81 with the plurality of measured values S1, S2, S3, ... And the misregistration amount R described above as observation variables. This infers the causal relationship between the observed variables. FIG. 5 is an example of a chart showing the causal relationship between the observed variables estimated by the statistical causal search program 81. In the example of FIG. 5, the rotation speed S1 of the first motor, the torque S2 of the first motor, the tension S3 of the base material 9, the vertical displacement S4 of the base material 9, the rotation speed S5 of the second motor, and the torque of the second motor The causal relationship between the six measured values of S6 and the displacement amount R for a total of seven observed variables is shown.

The arrows in FIG. 5 indicate the causal relationship between the two observed variables. The base end side of the arrow is the observed variable (factor) that affects it. The tip of the arrow is the observed variable (result) affected. Further, as shown in FIG. 5, when the statistical causal search program 81 is operated, the strength of the causal relationship between the observed variables is output as a numerical value for each of these arrows.

The storage unit 503 of the control unit 50 stores in advance a threshold value for the strength of the causal relationship. The calculation unit 52 ignores the arrows whose intensity is less than the threshold value and selects only the arrows whose intensity is equal to or more than the threshold value among the arrows between the observed variables obtained by the statistical causal search program 81. For example, in the chart of FIG. 5, when the threshold value is 0.06, as shown in FIG. 6, a chart focusing only on the arrows having an intensity of 0.06 or more can be obtained.

Since the values of the observed variables S1 to S6 and R change with time, the value of the intensity of each arrow also changes with time. Therefore, the combination of arrows selected in FIG. 6 may change over time.

Subsequently, the calculation unit 52 determines the impact values V1, V2, V3 indicating the degree of influence of each measured value S1, S2, S3, ... On the misregistration amount R based on the strength of the causal relationship of the selected arrow. , ... are calculated. As described above, the calculation process of the impact values V1, V2, V3, ... Is executed only for the arrows whose causal strength is equal to or greater than the threshold value. By ignoring the intensity below the threshold value, the impact values V1, V2, V3, ... Can be calculated while removing noise and reducing the calculation load.

In the example of FIG. 6, among the plurality of measured values S1 to S6, the vertical displacement S4 of the base material 9 and the rotation speed S5 of the second motor are directly connected to the misregistration amount R by an arrow. That is, these measured values S4 and S5 directly affect the misregistration amount R. In this case, the calculation unit 52 sets the strength of the causal relationship between the measured values S4 and S5 with respect to the misregistration amount R as the impact values V4 and V5. That is, the strength of the arrow from the vertical displacement S4 toward the misregistration amount R is defined as the impact value V4 of the vertical displacement S4. Further, the strength of the arrow from the rotation speed S5 of the second motor toward the misregistration amount R is defined as the impact value V5 of the rotation speed S5 of the second motor.

Further, in the example of FIG. 6, among the plurality of measured values S1 to S6, the rotation speed S1 of the first motor, the torque S2 of the first motor, and the tension S3 of the base material 9 cause the vertical displacement S4 of the base material 9. It is indirectly connected to the misregistration amount R via. That is, these measured values S1 to S3 indirectly affect the misregistration amount R. In this case, the calculation unit 52 calculates the impact values V1 to V3 based on the intensities of the plurality of arrows existing between the measured values S1 to S3 and the misregistration amount R.

For example, the integrated value of the strength of the arrow from the rotational speed S1 of the first motor to the vertical displacement S4 and the strength of the arrow from the vertical displacement S4 to the misregistration amount R is the impact value of the rotational speed S1 of the first motor. Let it be V1. Further, the integrated value of the strength of the arrow from the torque S2 of the first motor to the vertical displacement S4 and the strength of the arrow from the vertical displacement S4 to the misregistration amount R is taken as the impact value V2 of the torque S2 of the first motor. do. Further, the integrated value of the strength of the arrow from the tension S3 toward the vertical displacement S4 and the strength of the arrow from the vertical displacement S4 toward the misregistration amount R is taken as the impact value V3 of the tension S3.

Further, in the example of FIG. 6, the torque S6 of the second motor has two routes, a route via the vertical displacement S4 of the base material 9 and a route via the rotation speed S5 of the second motor, and has a misregistration amount R. Indirectly connected. In this case, the calculation unit 52 calculates the impact value V6 based on the intensities of the plurality of arrows in the two routes. For example, the calculation unit 52 sets the sum of the integrated value of the strength of the arrow on one route and the integrated value of the intensity of the arrow on the other route as the impact value V2 of the torque S6 of the second motor.

However, the calculation unit 52 may calculate each impact value V1, V2, V3, ... By a calculation method different from the above, based on the intensity of the arrow output by the statistical causal search program 81.

In this way, the calculation unit 52 calculates the impact values V1, V2, V3, ... For each of the measured values S1, S2, S3, ... That is, the calculation unit 52 calculates the impact values V1, V2, V3, ... For each measurement point of the sensor 30. The impact values V1, V2, V3, ... Are calculated as time-series data that changes with the passage of time. FIG. 7 is a graph showing an example of changes with time of impact values V1, V2, V3, ...

The specifying unit 53 identifies, among the plurality of measurement points, the measurement points having a high degree of influence on the misregistration amount R, based on the changes over time of the impact values V1, V2, V3, ... Calculated by the calculation unit 52. In the example of FIG. 7, the impact value V1 of the rotation speed S1 of the first motor is periodically increased. Therefore, it can be understood that the rotation speed S1 of the motor periodically affects the misregistration amount R. Further, the impact value V6 of the torque S6 of the second motor is momentarily very high at a certain timing. Therefore, it can be understood that the torque S6 of the second motor temporarily has a strong influence on the misregistration amount R.

The specifying unit 53 identifies a measurement point having a high degree of influence on the misregistration amount R by comparing each impact value V1, V2, V3, ... With a preset threshold value. However, the specific unit 53 determines a measurement point having a high degree of influence on the misregistration amount R by comparing the value calculated by substituting each impact value V1, V2, V3, ... It may be specified. For example, the specifying unit 53 may specify a measurement point having a high degree of influence on the misregistration amount R based on the rate of change of each impact value V1, V2, V3, ....

The output unit 54 outputs the information of the measurement point specified by the specific unit 53. For example, the output unit 54 may output the graph of the change with time of the impact values V1, V2, V3, ... As shown in FIG. 7 as it is. Further, the output unit 54 may output information on the measurement location corresponding to the measured value when the impact value of some of the measured values exceeds a preset threshold value. The output unit 54 displays and outputs the information on the display 56 connected to the control unit 50. However, the form of output may be audio output, data transmission to another computer, lighting of a lamp, printing, or the like. By checking the output information, the user of the printing apparatus 1 can grasp the measurement points affecting the misregistration amount R.

The adjusting unit 55 adjusts the measurement point specified by the specific unit 53. For example, if the impact value V1 of the rotation speed S1 of the first motor continues to be high, the adjusting unit 55 adjusts the first motor. At this time, the adjusting unit 55 adjusts the first motor so that the misregistration amount R becomes small. Further, when there are a plurality of measurement points specified by the specific unit 53, the adjustment unit 55 adjusts each of the measurement points. As a result, the influence of each measurement point on the misregistration amount R can be reduced. Therefore, it is possible to suppress the mutual positional deviation of the ink droplets ejected from the four heads 21 to 24 onto the upper surface of the base material 9.

<3. Modification example>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

In the above embodiment, the adjusting unit 55 automatically adjusts the measurement point specified by the specific unit 53. However, it is not essential that the control unit 50 has the adjustment unit 55. The user who has confirmed the information output from the output unit 54 may manually adjust the measurement point specified by the specific unit 53.

Further, in the above embodiment, the calculation unit 52 selects only those having a strength of the causal relationship between the two variables equal to or greater than the threshold value, and calculates the impact values V1, V2, V3, ... However, the calculation unit 52 may calculate the impact values V1, V2, V3, ... Based on the strength of the causal relationship between all the two variables.

Further, in the above embodiment, the LiNGAM program is mentioned as an example of the statistical causal search program 81. However, the statistical causal search program 81 used in the calculation unit 52 may be a program other than the LiNGAM program. The method of statistical causal search is not limited to a semi-parametric approach such as LiNGAM, and may be a parametric approach or a non-parametric approach.

Further, in the above embodiment, as shown in FIG. 2, the nozzles 201 are arranged in a row in the width direction in each of the heads 21 to 24. However, in each of the heads 21 to 24, the nozzles 201 may be arranged in two or more rows.

Further, the printing apparatus 1 of the above embodiment includes four heads 21 to 24. However, the number of heads included in the printing apparatus 1 may be 2, 3, or 5 or more. For example, the printing apparatus 1 may include a head that ejects a special color ink in addition to each of the colors C, M, Y, and K.

Further, the elements appearing in the above-described embodiments and modifications may be appropriately combined as long as there is no contradiction.

1 Printing device 9 Base material 10 Transfer mechanism 20 Printing unit 21 1st head 22 2nd head 23 3rd head 24 4th head 30 Sensor 40 Camera 50 Control unit 51 Detection unit 52 Calculation unit 53 Specific unit 54 Output unit 55 Adjustment unit 56 Display 80 Computer program 81 Statistical causal search program I Captured image R Misregistration amount S1 to S6 Measured value V1 to V6 Impact value

Claims (14)

A transport mechanism that transports a long strip-shaped base material in the longitudinal direction along a predetermined transport path,
A plurality of heads that eject ink onto the surface of the base material transported by the transport mechanism, and
Multiple sensors that measure the status of multiple measurement points in the device, and
A camera that photographs the surface of the base material on the downstream side of the transport path from the plurality of heads.
A control unit communicatively connected to the plurality of sensors and the camera,
Equipped with
The control unit
A detection unit that detects the amount of mutual misalignment of ink ejected from the plurality of heads to the surface of the base material based on the captured image obtained from the camera.
Calculation that acquires the measured value from the plurality of sensors, acquires the misalignment amount from the detection unit, and calculates the impact value indicating the degree of influence of the measured value on the misalignment amount for each measurement location. Department and
A specific unit that identifies a measurement point having a high degree of influence on the amount of misalignment among the plurality of measurement points based on the plurality of impact values.
Has a printing device. The printing apparatus according to claim 1.
The calculation unit calculates the impact value as time-series data for each measurement point.
The specific unit is a printing device that identifies a measurement point having a high degree of influence on the amount of misalignment based on the change over time of the impact value. The printing apparatus according to claim 1 or 2.
The calculation unit estimates the causal relationship between the observed variables by using a statistical causal search program with the plurality of measured values and the amount of misalignment as observed variables, and the strength of the causal relationship between the observed variables. A printing device that calculates the impact value based on. The printing apparatus according to claim 3.
The statistical causal search program is a printing device, which is a LiNGAM program. The printing apparatus according to claim 3 or 4.
The calculation unit selects a causal relationship whose intensity is equal to or higher than a threshold value from a plurality of causal relationships among the plurality of observation variables, and calculates the impact value based on the intensity of the selected causal relationship. Device. The printing apparatus according to any one of claims 1 to 5.
The control unit
A printing apparatus further comprising an output unit that outputs information on a measurement point specified by the specific unit. The printing apparatus according to any one of claims 1 to 6.
The control unit
A printing apparatus further comprising an adjusting unit for adjusting a measurement point specified by the specific unit so that the amount of misalignment is small. It is a management method of a printing device that ejects ink from a plurality of heads to the surface of a substrate while conveying a long strip-shaped substrate in the longitudinal direction along a predetermined transport path.
a) A process of measuring the state of a plurality of measurement points in the printing apparatus, and
b) A step of detecting the amount of mutual misalignment of the ink ejected from the plurality of heads to the surface of the base material, and
c) A step of calculating an impact value indicating the degree of influence of the measured value acquired in the step a) on the amount of misalignment detected in the step b) for each measurement point.
d) A step of identifying a measurement point having a high degree of influence on the amount of misalignment among the plurality of measurement points based on the plurality of impact values.
Management method with. The management method according to claim 8.
In the step c), the impact value is calculated as time-series data for each measurement point.
In the step d), a management method for specifying a measurement point having a high degree of influence on the amount of misalignment based on the change over time of the impact value. The management method according to claim 8 or 9.
In the step c), the causal relationship between the observed variables is estimated by the statistical causal search program using the plurality of measured values and the displacement amount as the observed variables, and the causal relationship between the observed variables is estimated. A management method for calculating the impact value based on the strength. The management method according to claim 10.
The statistical causal search program is a LiNGAM program, a management method. The management method according to claim 10 or 11.
The step c) is
c1) A step of selecting a causal relationship having an intensity equal to or higher than a threshold value among a plurality of causal relationships between the plurality of observed variables.
c2) The step of calculating the impact value based on the strength of the causal relationship selected in the step c1), and
Has a management method. The management method according to any one of claims 8 to 12.
e) A management method further comprising a step of outputting information on a measurement point specified by the step d). The management method according to any one of claims 8 to 13.
f) A management method further comprising a step of adjusting the measurement point specified by the step d) so that the amount of misalignment is small.

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