Printing equipment and printing method

Abstract

The present invention provides a printing device and printing method that can accurately and immediately determine whether or not characters are properly printed on the surface of a steel material, even when the size and position of the characters printed on the surface of the steel material vary. [Solution] The control device for the printing equipment performs the following actions while the printing device and the imaging device are moving relative to the steel material: control the printing device to print characters on the surface of the steel material; control the imaging device to capture an image of the area on the surface of the steel material that includes the characters and generate an image; and process the capture image to determine the quality of the characters based on the image, using an artificial intelligence model that has learned the relationship between the characters and quality in the image.

Description

Technical Field

[0001] The present invention relates to printing equipment and a printing method.

Background Art

[0002] In the technical field of steel materials, in order to manage steel materials, characters such as management numbers may be printed on the surface of the steel materials. If the characters are not properly printed on the surface of the steel materials, steel materials that are difficult to manage may flow out as products. Therefore, it is required to prevent the outflow of steel materials with characters not properly printed on their surfaces. Also, it is desired to perform an inspection on whether the characters are properly printed on the surface of the steel materials by means of a full inspection rather than a sampling inspection. Furthermore, it is desired that the inspection be carried out immediately after the printing of the characters.

[0003] Here, for the inspection of whether the characters are properly printed on the surface of the steel materials, it is conceivable to use a pattern matching technique for collating the characters printed on the surface of the steel materials with a predetermined pattern, an OCR (Optical Character Recognition) technique for reading the characters printed on the surface of the steel materials, and the like. However, for example, when printing characters on the surface of the steel materials while conveying the steel materials, the size and position of the characters printed on the surface of the steel materials may vary due to the displacement of the position of the printing device with respect to the steel materials or the fluctuation of the conveying speed. Therefore, it is desired to accurately determine whether the characters are properly printed on the surface of the steel materials even when the size and position of the characters printed on the surface of the steel materials vary.

[0004] Patent Document 1 discloses an identification device for identifying characters displayed on the surface of a steel plate, comprising: an image capturing means for capturing an image including characters on the surface of the steel plate; and a character recognition means for recognizing characters from the captured image, wherein the character recognition means includes: an image processing unit for absolutely or relatively binarizing the image at a predetermined threshold; a character extraction unit for determining the region in which characters are written from the image binarized by the image processing unit and extracting the character image portion; a match ratio acquisition unit for obtaining a match ratio by comparing the extracted character image portion with registered characters stored in advance; and a character identification unit for determining one of the registered characters whose match ratio with the character image portion is equal to or greater than a predetermined value as the recognition character represented by the character image portion.

[0005] Furthermore, Patent Document 2 discloses an identification device for identifying articles, comprising: an image acquisition unit that acquires one or more captured images of a region containing first information which is information displayed on an article; a recognition unit that recognizes at least one piece of first information based on the captured images acquired by the image acquisition unit; a comparison unit that compares at least a portion of the first recognition information which is the first information recognized by the recognition unit with first stored information which is the first information pre-stored in a storage medium as one of the stored information; and a specification unit that identifies at least one candidate article based on the result of the comparison by the comparison unit, wherein the comparison unit can compare recognition information which is partially different from the first recognition information with stored information which is pre-stored in the storage medium as information corresponding to the recognition information.

[0006] Furthermore, Patent Document 3 describes a method for determining the quality of white characters printed on the outer surface of a steel pipe in a steel pipe manufacturing line, and the area S (mm²) of the white area when predetermined characters are completely printed as a printing area for quality determination. 2The following steps are taken: ) are determined in advance; a pass / fail judgment mark is printed on each individual steel pipe; the steel pipe with the pass / fail judgment mark is placed on a specific pass line with the pass / fail judgment mark facing upwards; a fixed camera positioned at a predetermined distance above the pass line and shooting downwards is used to photograph a predetermined area including the pass / fail judgment mark; and for each individual steel pipe, the projected area S of the white portion when the predetermined characters are completely printed is determined. p (mm 2 In addition to calculating the area S0 (mm²) of the white area photographed for the actual printed pass / fail judgment section, the area of ​​the white part of the printed section was also calculated. 2 ) is measured, and the projected area S of the white area when fully printed is measured. P The judgment index D(%) = 100 × S0 / S is expressed as the ratio of the area S0 of the captured white area to the total area. P A method for determining the quality of printing on the outer surface of a steel pipe is disclosed, characterized by calculating a judgment index D and then comparing the calculated judgment index D with a pre-set threshold to determine the quality of the printing.

[0007] Furthermore, Patent Document 4 discloses a character recognition device that recognizes characters displayed on the surface of an object, comprising: an imaging unit that captures images of the surface of an object and generates an image under conditions where the positional relationship with the object is not constant; and an arithmetic processing unit that recognizes characters displayed on the surface of the object based on the image. The arithmetic processing unit comprises: a first character recognition unit that performs character recognition based on the image; a line acquisition unit that acquires a line corresponding to the horizontal direction of the characters displayed on the surface of the object and a line corresponding to the vertical direction of the characters displayed on the surface of the object based on rectangular information recognized by the character recognition by the first character recognition unit; a frontal orientation transformation unit that generates a transformed image by transforming the image so that the characters displayed on the surface of the object are viewed from the front, based on the horizontal and vertical lines acquired by the line acquisition unit; and a second character recognition unit that performs character recognition based on the transformed image, and outputs the characters recognized by the second character recognition unit. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2024-46908 [Patent Document 2] International Publication No. 2022 / 092147 Brochure [Patent Document 3] Japanese Patent Publication No. 2009-245337 [Patent Document 4] Japanese Patent Publication No. 2023-143387 [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention aims to provide printing equipment and a printing method that can accurately and immediately determine whether or not characters are properly printed on the surface of a steel material, even when the size and position of the characters printed on the surface of the steel material vary. [Means for solving the problem]

[0010] A first aspect of the present invention comprises a printing device for printing characters on the surface of a steel material, an imaging device for imaging the surface of the steel material, a moving device for moving the printing device and the imaging device relative to the steel material, and a control device for controlling the printing device, the imaging device, and the moving device, wherein the control device includes a moving control unit that controls the moving device to move the printing device and the imaging device relative to the steel material, and while the printing device and the imaging device are moving relative to the steel material, the control device controls the printing device to move the surface of the steel material The printing equipment comprises: a printing control unit that controls the printing of the aforementioned characters; an imaging control unit that controls the imaging unit to capture an image of the region on the surface of the steel material that includes the aforementioned characters while the printing unit and the imaging unit are moving relative to the steel material, thereby generating an image; and a determination processing unit that, while the printing unit and the imaging unit are moving relative to the steel material, uses an artificial intelligence model that has learned the relationship between the characters and quality in the image to determine the quality of the characters based on the image.

[0011] A second aspect of the present invention is a printing apparatus according to the first aspect, wherein the artificial intelligence model acquires rectangular information indicating at least one of the size and position of a rectangle corresponding to the character captured in the image, and outputs a result of determining the quality of the character based on the rectangular information.

[0012] A third aspect of the present invention is a printing apparatus according to the second aspect, wherein the printing control unit controls the printing device to print a plurality of characters on the surface of the steel material, and the artificial intelligence model outputs a result of determining the quality of the plurality of characters according to the relative positional relationship of rectangles corresponding to the plurality of characters.

[0013] A fourth aspect of the present invention is a printing method using a printing apparatus comprising: a printing device for printing characters on the surface of a steel material; an imaging device for imaging the surface of the steel material; a moving device for moving the printing device and the imaging device relative to the steel material; and a control device for controlling the printing device, the imaging device, and the moving device, wherein the printing apparatus comprises: a moving step in which the moving device moves the printing device and the imaging device relative to the steel material; a printing step in which the printing device prints the characters on the surface of the steel material while the printing device and the imaging device are moving relative to the steel material; an imaging step in which the imaging device images a region of the surface of the steel material including the characters while the printing device and the imaging device are moving relative to the steel material to generate an image; and a determination step in which the control device determines the quality of the characters based on the image, using an artificial intelligence model that has learned the relationship between the characters and quality in the image, while the printing device and the imaging device are moving relative to the steel material. [Effects of the Invention]

[0014] According to the present invention, a printing apparatus and printing method are provided that can accurately and immediately determine whether or not characters are properly printed on the surface of a steel material, even when the size and position of the characters printed on the surface of the steel material vary.

Brief Description of the Drawings

[0015] [Figure 1] It is a plan view schematically showing an example of printing equipment according to the first embodiment of the present invention. [Figure 2] It is a block diagram showing an example of the functional configuration of a control device according to the first embodiment of the present invention. [Figure 3] It is a diagram showing a first example of a captured image. [Figure 4] It is a diagram showing a second example of a captured image. [Figure 5] It is a diagram showing a third example of a captured image. [Figure 6] It is a diagram showing a fourth example of a captured image. [Figure 7] It is a diagram showing a fifth example of a captured image. [Figure 8] It is a block diagram showing an example of the hardware configuration of a control device. [Figure 9] It is a flowchart showing an example of the flow of a printing method according to the first embodiment of the present invention. [Figure 10] It is a plan view schematically showing an example of printing equipment according to the second embodiment of the present invention. [Figure 11] It is a block diagram showing an example of the functional configuration of a control device according to the second embodiment of the present invention.

Modes for Carrying Out the Invention

[0016] [First Embodiment] First, the printing equipment 10 according to the first embodiment of the present invention will be described.

[0017] Figure 1 shows an example of a printing apparatus 10 according to the first embodiment of the present invention. In addition to the function of printing characters on the surface of a steel material 12, the printing apparatus 10 has a function of determining whether the printed characters are properly printed. The indicator for determining whether the printed characters are properly printed is set in advance, for example, according to the specifications required for the steel material 12 as a regular product. The steel material 12 to be printed by the printing apparatus 10 may be any of the following, such as a steel plate, steel pipe, structural steel, and steel bar. The following explanation will use the case where the steel material 12 is a steel pipe as an example.

[0018] The printing equipment 10 comprises a printing device 14, an imaging device 16, a transport device 18, and a control device 20. The printing device 14 is a device that prints characters, for example, a management number, on the surface of the steel material 12. For example, a stencil machine can be used as the printing device 14. The printing device 14 can simultaneously print characters on multiple steel materials 12 placed on the transport mechanism 22, which will be described later. The printing device 14 prints multiple characters on each steel material 12 along the transport direction of the steel material 12. Hereinafter, the direction in which the printing device 14 prints multiple characters will be referred to as the "printing direction". The imaging device 16 is a device that images the surface of the steel material 12. For example, a digital camera or a CCD (Charge Coupled Device) camera can be used as the imaging device 16. The imaging device 16 is located downstream of the printing device 14 in the transport direction.

[0019] The conveying device 18 is a device that conveys the steel materials 12 in the conveying direction. The conveying device 18 is an example of a "moving device" in the present invention. The conveying device 18 comprises a conveying mechanism 22 and a drive mechanism (not shown). The conveying mechanism 22 has a size and structure that allows it to hold a plurality of steel materials 12. The conveying mechanism 22 is, for example, a belt conveyor. The drive mechanism is, for example, a motor drive mechanism, which operates the conveying mechanism 22 to convey the plurality of steel materials 12 in the conveying direction. Each steel material 12 is elongated and is arranged on the conveying mechanism 22 along the conveying direction. The plurality of steel materials 12 are arranged in a line perpendicular to the conveying direction in a plan view. The control device 20 is a device that controls the printing device 14, the imaging device 16, and the conveying device 18, and is connected to the printing device 14, the imaging device 16, and the conveying device 18 by wire or wireless.

[0020] Figure 2 shows an example of the functional configuration of the control device 20. The control device 20 comprises a transport control unit 30, a printing control unit 32, an imaging control unit 34, a determination processing unit 36, and a storage unit 38. The control device 20 is a device that performs various controls and calculations related to the printing equipment 10, and is composed of a computer with a hardware configuration described later.

[0021] The transport control unit 30 controls the transport device 18 to transport multiple steel materials 12 in the transport direction. The transport control unit 30 is an example of a "movement control unit" in the present invention. The transport control unit 30 starts transporting when it receives a command to start transport from an external source. The printing control unit 32 controls the printing device 14 to print multiple characters on the surface of each steel material 12 along the transport direction while the multiple steel materials 12 are being transported. The printing control unit 32 controls the printing device 14 to print multiple characters in an area located at a predetermined distance from the end 12A of the steel material 12. The end 12A of the steel material 12 is detected, for example, by a sensor (not shown) provided on the printing device 14. The position at a predetermined distance from the end 12A of the steel material 12 is derived, for example, based on the elapsed time since the end 12A of the steel material 12 was detected and the transport speed of the steel material 12.

[0022] The imaging control unit 34 controls the imaging device 16 to image an area on the surface of each steel material 12 that includes at least several characters, while the multiple steel materials 12 are being transported, in order to generate an image 60 (see, for example, Figures 3 to 7). The imaging control unit 34 may generate multiple image 60 by having the imaging device 16 take continuous images, or it may generate a single image 60 by having the imaging device 16 take images with the end 12A of the steel material 12 to the multiple characters included in its field of view. The control device 20 receives the image 60 from the imaging device 16. If the control device 20 receives multiple image 60 from the imaging device 16, it may combine the multiple image 60 to generate a single image 60.

[0023] The judgment processing unit 36 ​​performs a process to determine the quality of each character based on the captured image 60, using an artificial intelligence model 52 stored in the memory unit 38, while multiple steel materials 12 are being transported. The artificial intelligence model 52 uses, for example, a neural network (specifically, a convolutional neural network such as YOLO). The artificial intelligence model 52 uses, for example, a bounding box method to obtain rectangular information from the captured image 60 that indicates the size and position of the rectangle corresponding to the character captured in the captured image 60 for each of the multiple characters on each steel material 12. The artificial intelligence model 52 then outputs the result of determining the quality of the multiple characters for each steel material 12 based on the rectangular information. If the transport control unit 30 receives a good judgment result from the judgment processing unit 36, it continues transporting; if it receives a bad judgment result, it stops transporting.

[0024] The artificial intelligence model 52 may output the results of determining the quality of each character for each steel material 12, or it may output the results of determining the quality of the entire set of characters for each steel material 12. The determination results may be displayed on a display (not shown) or stored in the memory unit 38. The size of the rectangle corresponding to the character is derived, for example, based on the number of pixels within the rectangle. The position of the character in the captured image 60 is derived, for example, based on the position of the rectangle (for example, the center or corner of the rectangle) relative to a predetermined reference position (for example, the center or corner of the captured image 60) for the captured image 60. The rectangle information may include both the size and position of the rectangle, or it may indicate only one of the size or position of the rectangle. The following explanation will use the case where the rectangle information includes both the size and position of the rectangle as an example.

[0025] The artificial intelligence model 52 is a computer program model that has learned the relationship between characters and quality in captured images 60. The artificial intelligence model 52 is constructed using training data, such as deep learning, with captured images 60 of multiple steel materials 12 used for training as input data and the quality of the characters printed in the input captured images 60 as output data. The training data includes training data obtained while the steel materials 12 are being transported normally, training data obtained when the position of the printing device 14 is misaligned with respect to the steel materials 12, and training data obtained when the transport speed of the steel materials 12 is fluctuating. While the steel materials 12 are being transported normally, characters are printed normally on the surface of the steel materials 12. However, when the position of the printing device 14 is misaligned with respect to the steel materials 12 or when the transport speed of the steel materials 12 is fluctuating, the size and position of the characters printed on the surface of the steel materials 12 are misaligned.

[0026] Figures 3 to 7 show examples of captured images 60. Below, the process of determining whether an image is good or bad by the artificial intelligence model 52 will be explained in more detail, using the example of a case where the letters "ABCDEFG" are printed as multiple characters on the surface of the steel material 12. The artificial intelligence model 52 obtains rectangular information for each of the "ABCDEFG" characters from the captured images 60, and based on the rectangular information, obtains the height value, width value, position in the printing direction, and position in the direction perpendicular to the printing direction (hereinafter referred to as the "vertical direction") for each of the "ABCDEFG" characters.

[0027] In the example of the captured image 60 shown in Figure 3, the artificial intelligence model 52 obtains the height value of each character of "ABCDEFG" based on the rectangular information, and outputs a result of determining the quality of multiple characters based on the height values ​​of each character of "ABCDEFG" and a preset character height threshold. In the example shown in Figure 3, the height value of the character "F" is smaller than the threshold because the position of the printing device 14 and the steel material 12 is closer than the normal position. If the height value of the character "F" is smaller than the threshold, the artificial intelligence model 52 outputs a result indicating that it is defective. The artificial intelligence model 52 may output a result indicating that only the characters in "ABCDEFG" whose character height value is smaller than the threshold are defective, or it may output a result indicating that all of the characters in "ABCDEFG" are defective. Furthermore, the artificial intelligence model 52 may include the fact that the character height value is smaller than the threshold as a defect item in the result indicating that it is defective. The preset character height threshold may be the same for each character or may be different for each character. Furthermore, the artificial intelligence model 52 may output a result indicating a defect if the character height value is greater than a threshold.

[0028] Furthermore, in the example of the captured image 60 shown in Figure 4, the artificial intelligence model 52 obtains the width value of each character of "ABCDEFG" based on the rectangular information, and outputs a result of determining the quality of multiple characters based on the width values ​​of each character of "ABCDEFG" and a preset character width threshold. In the example shown in Figure 4, the width value of the character "E" is greater than the threshold because the position of the printing device 14 and the steel material 12 is farther than the normal position, or the transport speed is higher than the normal speed. If the width value of the character "E" is greater than the threshold, the artificial intelligence model 52 outputs a result indicating that it is defective. Note that the artificial intelligence model 52 may output a result indicating that only the characters in "ABCDEFG" whose width value is greater than the threshold are defective, or it may output a result indicating that all of the characters in "ABCDEFG" are defective. In addition, the artificial intelligence model 52 may include the fact that the width value of the characters is greater than the threshold as a defect item in the result indicating that it is defective. The pre-set threshold for the width of each character may be the same or different for each character. Furthermore, the artificial intelligence model 52 may output a result indicating a defect if the width of a character is smaller than the threshold.

[0029] Furthermore, in the example of the captured image 60 shown in Figure 5, the artificial intelligence model 52 obtains the printing direction position of each character of "ABCDEFG" based on the rectangle information, and outputs a result of determining the quality of multiple characters based on the position of each character of "ABCDEFG". In other words, the artificial intelligence model 52 outputs a result of determining the quality of multiple characters according to the relative positional relationship of the rectangles corresponding to each character of "ABCDEFG". In the example shown in Figure 5, some of the adjacent characters of "ABCDEFG" overlap because the transport speed is lower than the normal speed. When some of the adjacent characters of "ABCDEFG" overlap, the artificial intelligence model 52 outputs a result indicating that it is defective. Note that the artificial intelligence model 52 may output a result indicating that it is defective if at least some of the adjacent characters of "ABCDEFG" overlap. Alternatively, the artificial intelligence model 52 may output a result indicating that only the characters of "ABCDEFG" that overlap are defective, or it may output a result indicating that the entire "ABCDEFG" is defective. Furthermore, the artificial intelligence model 52 may include, as a defect item, that at least a portion of any adjacent characters overlap. Also, the artificial intelligence model 52 may output a defect result if the distance between adjacent characters is greater than a predetermined threshold.

[0030] Furthermore, in the example of the captured image 60 shown in Figure 6, the artificial intelligence model 52 obtains the vertical position of each character of "ABCDEFG" based on the rectangular information, and outputs a result of determining the quality of multiple characters based on the position of each character of "ABCDEFG". In other words, the artificial intelligence model 52 outputs a result of determining the quality of multiple characters according to the relative positional relationship of the rectangles corresponding to each character of "ABCDEFG". In the example shown in Figure 6, the characters of "ABCDEFG" are meandering because the transported steel material 12 is swaying in a direction perpendicular to the transport direction. If the characters of "ABCDEFG" are meandering, that is, if the vertical displacement value of adjacent characters of "ABCDEFG" is greater than a preset threshold, and the displacement value continuously increases or decreases in the printing direction, the artificial intelligence model 52 outputs a result indicating that it is defective. In this case, the artificial intelligence model 52 may also include the fact that the characters of "ABCDEFG" are meandering. Furthermore, the artificial intelligence model 52 may output a result indicating a defect if the vertical displacement of at least one adjacent character in the letters "ABCDEFG" is greater than a threshold. Alternatively, the artificial intelligence model 52 may output a result indicating a defect only for the characters in "ABCDEFG" that are vertically shifted, or it may output a result indicating that the entire set of characters "ABCDEFG" is defective. In addition, the artificial intelligence model 52 may include the fact that at least one character is vertically shifted as a defect item in the result indicating a defect.

[0031] Furthermore, in the example of the captured image 60 shown in Figure 7, the artificial intelligence model 52 obtains the vertical position of each character of "ABCDEFG" based on the rectangular information, and outputs a result of determining the quality of multiple characters based on the position of each character of "ABCDEFG". In other words, the artificial intelligence model 52 outputs a result of determining the quality of multiple characters according to the relative positional relationship of the rectangles corresponding to each character of "ABCDEFG". In the example shown in Figure 7, the characters of "ABCDEFG" are bent because the transported steel material 12 is moving in a direction perpendicular to the transport direction, or the steel material 12 is bent relative to the transport direction. If the characters of "ABCDEFG" are bent, that is, if the vertical displacement value of adjacent characters of "ABCDEFG" is greater than a preset threshold, and the displacement in the same direction is continuous in the printing direction, the artificial intelligence model 52 outputs a result indicating that it is defective. In this case, the artificial intelligence model 52 may also include the fact that the characters of "ABCDEFG" are bent.

[0032] Figure 8 shows an example of the hardware configuration of the control device 20. The control device 20 is composed of a computer. The control device 20 includes a CPU (Central Processing Unit) 90, memory 92, storage device 94, input device 96, output device 98, storage medium reader 100, and communication I / F (Interface) 102. Each component is connected to the others via a bus 104 so as to be able to communicate with each other.

[0033] The storage device 94 stores a program for performing surface condition inspection. The CPU 90 is a central processing unit that executes various programs and controls each component. Specifically, the CPU 90 reads the program from the storage device 94 and executes the program using memory 92 as a workspace. The CPU 90 controls each component and performs various calculations according to the program stored in the storage device 94.

[0034] Memory 92 is composed of RAM (Random Access Memory) and temporarily stores programs and data as a working area. Storage device 94 is composed of ROM (Read Only Memory), HDD (Hard Disk Drive), or SSD (Solid State Drive), etc., and stores various programs and data, including the operating system.

[0035] The input device 96 is a device for performing various types of input, such as a keyboard or mouse. The output device 98 is a device for outputting various types of information, such as a display or printer. A touch panel display may be used as the output device 98 and function as the input device 96.

[0036] The storage medium reader 100 reads data stored on various storage media such as CD (Compact Disc)-ROM, DVD (Digital Versatile Disc)-ROM, Blu-ray disc, or USB (Universal Serial Bus) memory, and writes data to the storage media. The communication I / F 102 is an interface for communicating with other devices. For example, the communication I / F 102 uses an interface that conforms to standards such as Ethernet (registered trademark), FDDI, or Wi-Fi (registered trademark).

[0037] Figure 9 shows an example of the flow of the printing method according to the first embodiment of the present invention. The printing method according to the first embodiment of the present invention is performed using the printing equipment 10 described above.

[0038] First, in step S1, the conveying device 18 starts a conveying step in which it conveys the steel material 12 in the conveying direction. The conveying step is an example of a "movement step" in the present invention.

[0039] Next, in step S2, while the steel material 12 is being transported in the transport direction, the printing device 14 performs a printing step in which it prints characters on the surface of the steel material 12.

[0040] Next, in step S3, while the steel material 12 is being transported in the transport direction, the imaging device 16 performs an imaging step in which it images the region of the surface of the steel material 12 that includes the characters to generate an image 60.

[0041] Next, in step S4, while the steel material 12 is being transported in the transport direction, the control device 20 uses the artificial intelligence model 52 to perform a determination step to determine the quality of the characters based on the captured image 60.

[0042] Next, in step S5, the control device 20 determines whether or not to terminate the transport. If the determination in step S4 is good, the control device 20 determines to continue the transport (step S5: NO) and executes the processes from step S2 to step S4 for the next steel material 12. On the other hand, if the determination in step S4 is bad, the control device 20 stops the transport (step S5: YES) and terminates the printing method.

[0043] As detailed above, in the first embodiment of the present invention, while the steel material 12 is being transported in the transport direction, the control device 20 uses the artificial intelligence model 52 to determine the quality of the characters based on the captured image 60. Therefore, compared to, for example, the case where pattern matching technology or OCR (Optical Character Recognition) technology is used, it is possible to accurately determine whether the characters are properly printed on the surface of the steel material 12, even if there are variations in the size and position of the characters printed on the surface of the steel material 12. In other words, by including in the training data used to train the artificial intelligence model 52 training data not only the training data obtained while the steel material 12 is being transported normally, but also training data obtained when the position of the printing device 14 is shifted relative to the steel material 12, and training data obtained when the transport speed of the steel material 12 is fluctuating, it is possible to accurately determine whether the characters are properly printed on the surface of the steel material 12, even if there are variations in the size and position of the characters printed on the surface of the steel material 12.

[0044] Furthermore, the control device 20 determines the quality of the characters while the steel material 12 is being transported in the transport direction, and performs the quality determination of the characters after the characters have been printed on the surface of the steel material 12. Therefore, it is possible to immediately determine whether or not the characters have been properly printed on the surface of the steel material 12.

[0045] Furthermore, the control device 20 is equipped with an artificial intelligence model 52, which acquires rectangular information indicating the size and position of the rectangle corresponding to the characters captured in the image 60, and outputs a result of determining the quality of the characters based on the rectangular information. Therefore, the detection accuracy of the size and position of characters printed on the surface of the steel material 12 can be improved.

[0046] Furthermore, the printing device 14 prints multiple characters, and the artificial intelligence model 52 outputs the result of determining the quality of the multiple characters based on the relative positional relationship of the rectangles corresponding to the multiple characters. This makes it possible to determine overlapping, meandering, and bending of multiple characters.

[0047] In the first embodiment, the printing control unit 32 controls the printing device 14 to print multiple characters on the surface of each steel material 12, but it may also control the device to print only one character on the surface of each steel material 12.

[0048] [Second Embodiment] Next, a printing apparatus 10 according to a second embodiment of the present invention will be described.

[0049] Figure 10 shows an example of a printing apparatus 210 according to a second embodiment of the present invention. The printing apparatus 210 has the following configuration changes compared to the printing apparatus 10 according to the first embodiment described above. The following describes the configuration of the printing apparatus 210, which differs from the printing apparatus 10 according to the first embodiment described above.

[0050] The printing equipment 10 comprises a first imaging device 16A and a second imaging device 16B. The first imaging device 16A and the second imaging device 16B are examples of "imaging devices" in the present invention. The first imaging device 16A is positioned on one side of the printing direction relative to the printing device 14, and the second imaging device 16B is positioned on the other side of the printing direction relative to the printing device 14. The first imaging device 16A and the second imaging device 16B are fixed to the printing device 14.

[0051] The printing device 14 has a drive device 24. The drive device 24 is an example of a "moving device" in the present invention. The drive device 24 is, for example, a motor drive device that moves the printing device 14 to one side and the other side in the printing direction. When the printing device 14 moves, the first imaging device 16A and the second imaging device 16B move together with the printing device 14. The transport direction of the steel material 12 is set to a direction perpendicular to the printing direction. In the second embodiment, the steel material 12 is transported one by one in the transport direction by the transport device 18.

[0052] Figure 11 shows an example of the functional configuration of the control device 20. The control device 20 includes, as a functional configuration, a transport control unit 30, a drive control unit 40, a printing control unit 32, an imaging control unit 34, a determination processing unit 36, and a storage unit 38.

[0053] The transport control unit 30 controls the transport device 18 to transport the steel material 12 in the transport direction. The drive control unit 40 controls the drive device 24 to move the printing device 14 to one side and the other side in the printing direction. By controlling the drive device 24, the drive control unit 40 causes the drive device 24 to perform a movement step that moves the printing device 14, the first imaging device 16A, and the second imaging device 16B in the printing direction. While the transport of the steel material 12 is stopped, the printing control unit 32 controls the printing device 14 to print characters on the surface of the steel material 12 while the printing device 14 is moving. For the first steel material 12, the printing control unit 32 controls the printing device 14 to move from one side to the other side in the printing direction on the steel material 12, and for the second steel material 12, it controls the printing device 14 to move from the other side to the one side in the printing direction. From this point onward, the printing control unit 32 switches between controlling the printing device 14 to move to one side of the printing direction and controlling it to move to the other side each time the steel material 12 on which the characters are printed is replaced.

[0054] The imaging control unit 34 controls the first imaging device 16A to capture an area containing multiple characters and generate an image 60 while the printing device 14 is moving from one side to the other in the printing direction on the steel material 12. The imaging control unit 34 also controls the second imaging device 16B to capture an area containing multiple characters and generate an image 60 while the printing device 14 is moving from the other side to the one side in the printing direction on the steel material 12. The judgment processing unit 36 ​​uses the artificial intelligence model 52 to determine the quality of the characters based on the image 60 generated by the first imaging device 16A while the printing device 14 is moving from one side to the other in the printing direction on the steel material 12. The judgment processing unit 36 ​​also uses the artificial intelligence model 52 to determine the quality of the characters based on the image 60 generated by the second imaging device 16B while the printing device 14 is moving from the other side to the one side in the printing direction on the steel material 12.

[0055] In the second embodiment described above, as in the first embodiment, even if the size and position of the characters printed on the surface of the steel material 12 vary, it is possible to accurately and immediately determine whether or not the characters are properly printed on the surface of the steel material 12.

[0056] Although the first and second embodiments of the present invention have been described above, the present invention is not limited to those described above, and it is of course possible to implement it in various modified forms without departing from the spirit of the invention. [Explanation of Symbols]

[0057] 10 Printing equipment 12 Steel materials 12A End of steel material 14 Printing device 16 Imaging device 16A First Imaging Device 16B Second Imaging Device 18 Conveying device 20 Control device 22 Conveying mechanism 24 Drive unit 30 Transport Control Unit 32 Printing Control Unit 34 Imaging Control Unit 36. Determination Processing Unit 38 Memory section 40 Drive control unit 52 Artificial Intelligence Models 60 captured images 90 CPU 92 memory 94 Storage device 96 Input device 98 Output device 100 Storage medium reader 102 Communication I / F 104 Bus 210 Printing equipment

Claims

1. A printing device for printing characters onto the surface of steel, An imaging device for imaging the surface of the steel material, A moving device for moving the printing device and the imaging device relative to the steel material, A control device for controlling the printing device, the imaging device, and the moving device, Equipped with, The control device is The moving device includes a movement control unit that controls the relative movement of the printing device and the imaging device with respect to the steel material, A printing control unit controls the printing device to print the characters on the surface of the steel material while the printing device and the imaging device are moving relative to the steel material, While the printing device and the imaging device are moving relative to the steel material, the imaging control unit controls the imaging device to image the region of the surface of the steel material that includes the characters and generate an image; While the printing device and the imaging device are moving relative to the steel material, a determination processing unit performs a process to determine the quality of the characters based on the captured image, using an artificial intelligence model that has learned the relationship between the characters and quality in the captured image. Printing equipment equipped with the following features.

2. The artificial intelligence model, Rectangular information is obtained that indicates at least one of the size and position of the rectangle corresponding to the character captured in the image. Based on the aforementioned rectangular information, the system outputs the result of determining whether the character is good or bad. The printing equipment according to claim 1.

3. The printing control unit controls the printing device to print a plurality of the characters on the surface of the steel material. The artificial intelligence model outputs a result of determining whether a plurality of characters are good or bad, based on the relative positional relationship of the rectangles corresponding to the plurality of characters. The printing apparatus according to claim 2.

4. A printing device for printing characters onto the surface of steel, An imaging device for imaging the surface of the steel material, A moving device for moving the printing device and the imaging device relative to the steel material, A control device for controlling the printing device, the imaging device, and the moving device, Using printing equipment equipped with, The moving device includes a moving step of moving the printing device and the imaging device relative to the steel material, The printing step involves printing the characters on the surface of the steel material while the printing device and the imaging device are moving relative to the steel material, The imaging step involves the imaging device capturing an image of the region on the surface of the steel material that includes the characters while the printing device and the imaging device are moving relative to the steel material, thereby generating an image. The control device, while the printing device and the imaging device are moving relative to the steel material, performs a determination step of determining the quality of the characters based on the captured image using an artificial intelligence model that has learned the relationship between the characters and quality in the captured image. A printing method comprising the following features.

Images