JP7549403B2 - Coating state inspection device, coating device, and coating state inspection method - Google Patents

Description

The present invention relates to a coating state inspection device, a coating device, and a coating state inspection method for inspecting the coating state of glue in a coating device that applies glue while transporting an object to be coated.

As a technique for inspecting the state of glue application, for example, Patent Document 1 discloses a gluing inspection device that alternately irradiates the glue-applied surface of an object to be glued, which is being transported in a predetermined direction at a predetermined speed, with reference infrared rays (e.g., wavelength 1300 nm) that are not absorbed by the glue and measurement infrared rays (e.g., wavelength 1450 nm) that are partially absorbed by the glue, and inspects the state of the glue application based on a comparison of the amount of reflected light of the reference infrared ray and the amount of reflected light of the measurement infrared ray.

JP 2018-84550 A

In a glue applicator that continuously applies glue to a workpiece while transporting it using a brush, sponge, roller, or other applicator, high-speed judgment processing is required to determine whether the glue application is good or bad. In addition, it is also necessary to perform judgment over a fairly wide area depending on the type and size of the applicator.

Furthermore, when the object to be coated and the glue are the same color, it is very difficult to see, making it difficult to judge the coating condition based on an image captured under visible light. In particular, when the glue is applied very thinly, it is extremely difficult to accurately detect smears or breaks in the glue as defects.

Regarding the wavelength of light irradiated onto the glue, if a reference infrared ray that is not absorbed by the glue and a measurement infrared ray that is partially absorbed by the glue are used as in Patent Document 1, it is necessary to provide two types of light sources, which makes the device configuration complicated. Also, in Patent Document 1, the infrared spot light is magnified by a magnifying lens and irradiated onto the glue, so it is only possible to cover a total width of the glue of about several mm to several tens of mm (see paragraph 0025 of Cited Document 1).

The present invention has been made in consideration of the above, and aims to provide a coating state inspection device, coating device, and coating state inspection method that can quickly, accurately, and with a simple configuration determine whether the coating state of glue is good or bad when glue is applied to a specified width using an application means such as a brush, sponge, or roller while transporting the object to be coated.

In order to solve the above problems, a coating state determination device according to one aspect of the present invention is a coating state inspection device for inspecting the coating state of a coating object in a coating device provided with a conveying means for conveying an object to be coated in a predetermined direction and a coating means for applying glue to the transported object to be coated in a predetermined width, the coating state inspection device comprising: a light source provided downstream of the coating means in the conveying direction of the object to be coated and irradiating near-infrared rays onto the object to be coated; a camera having sensitivity to near-infrared rays and for sequentially generating image data by capturing a moving image of the object to be coated irradiated with near-infrared rays by the light source; an image processing unit that acquires the image data generated by the camera and generates a plurality of frame images constituting a moving image in which the object to be coated is captured based on the image data, and detects an area where glue is applied in the width direction of the object to be coated, which is a direction perpendicular to the conveying direction, based on each of the plurality of frame images; and a determination unit that determines the coating state of the glue on the object to be coated based on the area detected by the image processing unit.

In the above-mentioned coating state inspection device, the image processing unit has a binarization processing unit that generates a binary image by performing binarization processing on each of the plurality of frame images, and a blob analysis unit that measures the widthwise length of the region by performing blob analysis on the binary image, and the judgment unit may judge the coating state of the glue based on the ratio of the widthwise length of the region to a predetermined glue coating width.

In the above coating condition inspection device, the judgment unit may judge the coating condition to be defective if the ratio is below a predetermined threshold value.

In the above coating condition inspection device, the judgment unit may warn of a defective coating condition when the ratio becomes equal to or less than a second threshold value that is greater than the threshold value.

In the above coating condition inspection device, the light source emits near-infrared light including a wavelength range of 800 nm or more and 950 nm or less, and the camera may be sensitive to the wavelength range of 800 nm or more and 950 nm or less.

In the above coating condition inspection device, the near-infrared light emitted by the light source may have a peak wavelength at least at 850 nm.

In the above coating state inspection device, the light source may be a surface light having a rectangular light-emitting surface.

In the above coating condition inspection device, the camera may operate at at least 60 fps.

In the above coating condition inspection device, the camera may be equipped with a CMOS image sensor.

In the above coating state inspection device, the conveying means may convey the coating object at a speed of at least 2 m/sec.

In the above coating state inspection device, the coating means may be configured to apply the glue to the object to be coated with a thickness of 100 μm or less.

A coating apparatus according to another aspect of the present invention includes the coating state inspection device, the transport means, and the coating means.
In the above coating device, the coating means may be a brush, a sponge, or a roller.

A coating state inspection method, which is yet another aspect of the present invention, is a coating state inspection method for inspecting the coating state of a glue applied to an object to be coated in a coating device provided with a conveying means for conveying an object to be coated in a predetermined direction and a coating means for applying glue to the conveyed object to be coated in a predetermined width, and includes an irradiation step of irradiating the object to be coated with near-infrared rays downstream of the coating means in the conveying direction of the object to be coated; an imaging step of sequentially generating image data by capturing a video of the object to be coated irradiated with near-infrared rays by the light source using a camera sensitive to near-infrared rays; an image processing step of acquiring the image data generated by the camera, generating a plurality of frame images constituting a video image in which the object to be coated is captured based on the image data, and detecting an area where glue is applied in the width direction, which is a direction perpendicular to the conveying direction of the object to be coated, based on each of the plurality of frame images; and a determination step of determining the coating state of the glue on the object to be coated based on the area detected in the image processing step.

According to the present invention, when applying glue to a specified width using an application means such as a brush, sponge or roller while transporting an object to be coated, it is possible to quickly, accurately and simply determine whether the state of the glue application is good or bad.

1 is a schematic diagram showing a schematic configuration of a coating apparatus according to an embodiment of the present invention. 1 is a schematic diagram showing a schematic configuration of a coating apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a schematic configuration of an inspection unit shown in FIG. 1 . 4 is a flowchart showing the operation of the inspection unit shown in FIG. 1 . FIG. 2 is a schematic diagram of a frame image captured using near-infrared light. FIG. 5 is a schematic diagram of a binary image of the frame image shown in FIG. 4 . 11 is a schematic diagram for explaining a method for measuring the coating detection width. FIG. FIG. 13 is a schematic diagram for explaining a method for determining the coating state.

The following describes the coating state inspection device, coating device, and coating state inspection method according to the embodiments of the present invention with reference to the drawings. Note that the present invention is not limited to these embodiments. In addition, in the descriptions of the drawings, the same parts are denoted by the same reference numerals.

The drawings referred to in the following description merely show the shape, size, and positional relationships in a schematic manner to enable the contents of the present invention to be understood. In other words, the present invention is not limited to the shape, size, and positional relationships illustrated in each drawing. Furthermore, there may be parts in which the dimensional relationships and ratios differ between the drawings.

(Embodiment)
1 and 2 are schematic diagrams showing a schematic configuration of a coating device according to an embodiment of the present invention. Of these, FIG. 1 shows a state in which a coating object is viewed from the side, and FIG. 2 shows a state in which a coating object is viewed from the top. As shown in FIGS. 1 and 2, the coating device 1 according to this embodiment includes a conveying section 3 that conveys a coating object 2 in a predetermined direction, a coating section 4 that applies glue to the coating object 2 in a predetermined width, and an inspection unit 5 as a coating state inspection device that inspects the coating state of the glue on the coating object 2. Hereinafter, among the horizontal directions, the conveying direction of the coating object 2 is also referred to as the x direction, and the direction perpendicular to the conveying direction, i.e., the width direction of the coating object 2 is also referred to as the y direction.

The object 2 to be coated is, for example, a long piece of paper, which is coated with glue by the coating unit 4 while being transported by the transport unit 3, and then processed by folding, overlapping, cutting, etc. However, the object 2 to be coated is not limited to a long piece of paper, and may be paper or cardboard that has been cut to a predetermined shape in advance, as well as sheet-like or plate-like members such as woven fabric, nonwoven fabric, and resin sheet.

The conveying unit 3 is a conveying means having a conveying belt 31 and two rotating drums 32. The two rotating drums 32 rotate about their respective rotation axes, thereby driving the conveying belt 31 arranged on the outer circumferential surfaces of these rotating drums 32. This causes the coating object 2 on the conveying belt 31 to be conveyed. However, the configuration of the conveying unit 3 is not limited to that shown in FIG. 1, so long as it is capable of conveying a sheet-like or plate-like member in a predetermined direction at a predetermined speed.

The application unit 4 is an application means including, for example, an application roller and a container for storing glue. The application unit 4 is provided with a moving means for moving the application unit 4 in the vertical direction (up and down direction in FIG. 1), and by moving the application unit 4 in the vertical direction, the application roller can be brought into contact with and removed from the application target 2. The application roller immersed in glue can be brought into contact with the application target 2 being transported, thereby applying glue. However, the configuration of the application unit 4 is not limited to that shown in FIG. 1, as long as it is an application means capable of continuously applying a predetermined width, such as a brush or application sponge.

Here, in this embodiment, "continuously applying" glue means applying glue over an area of a certain length (e.g., several centimeters or more) by contacting the application means with the transported coating object 2 for a predetermined period of time. Therefore, spot application of glue by dripping it onto the coating object is not included in "continuous application." Conversely, when glue is applied intermittently over a predetermined length using an application means such as a brush, sponge, or roller, it can be understood that the glue is applied continuously over the predetermined length.

The conveying unit 3 and the coating unit 4 operate under the control of a control device that comprehensively controls the operation of the coating device 1. In detail, the control device adjusts the conveying speed of the coating object 2, the timing of raising and lowering the coating unit 4, the position in the width direction where the coating unit 4 is installed, etc. based on a preset glue coating pattern and glue thickness. As an example, the conveying unit 3 may convey the coating object 2 at a speed of at least 2 m/sec so that the thickness of the glue applied to the coating object 2 is 100 μm or less.

The inspection unit 5 is a coating state inspection device that inspects the coating state of the glue applied to the coating object 2, and includes a light source 11 that emits near-infrared rays, a camera 12 that captures an image of the coating object 2 irradiated with near-infrared rays, and a computing device 13. Figure 3 is a block diagram showing the general configuration of the inspection unit 5.

The light source 11 is provided downstream of the coating section 4 in the conveying direction of the coating object 2, and irradiates the coating object 2 with near-infrared rays 11a. The near-infrared rays 11a emitted by the light source 11 include a wavelength range of 800 nm or more and 950 nm or less. It is preferable that the peak wavelength of this near-infrared rays 11a is near 850 nm. In addition, it is preferable to use a surface light having a rectangular light-emitting surface as the light source 11. By using a surface light, it is possible to illuminate the coating area 2a with a certain width with uniform illuminance. The irradiation area of the near-infrared rays 11a on the coating object 2 by the light source 11 only needs to cover the width of the predetermined glue coating area 2a. For example, an LED light (model number: LDL-74X27IR2-850, peak emission wavelength: 850 nm) manufactured by CCS Inc. can be used as the light source 11.

The camera 12 has sensitivity to near-infrared light, and sequentially generates image data by capturing video of the coating target 2 irradiated with near-infrared light by the light source 11 at a predetermined frame rate or higher. In detail, a camera equipped with a CMOS image sensor and having sensitivity to a wavelength range of 800 nm to 950 nm can be used as the camera 12. The sensitivity characteristic of the camera 12 to this wavelength range is not required to be very high, and may be, for example, about 30% to 40%.

The frame rate of the camera 12 is at least 60 fps, preferably 84 fps or more, and more preferably 167 fps or more. By using a camera 12 that operates at such a high speed, the coating state can be determined with high accuracy even when the conveying speed of the coating target 2 is fast (e.g., 2 m/sec or more). A specific example of such a camera 12 is a camera manufactured by Omron Sentec Co., Ltd. (model number: STC-MBCMU3V-NIR).

Here, in this embodiment, a camera equipped with an InGaAs image sensor that is commonly used in the near-infrared and infrared wavelength ranges is not used because it is difficult to capture images at a sufficient frame rate with an InGaAs image sensor, and cameras that use rare metals are expensive, which increases the manufacturing cost of the entire inspection unit.

The camera 12 is installed with its field of view 12a directed toward the glue application area 2a (see FIG. 2) irradiated with near-infrared rays 11a. At this time, the distance between the camera 12 and the object 2 to be glued is adjusted so that the field of view 12a of the camera covers the width of the glue application area 2a.

The calculation device 13 is configured by a general-purpose calculation processing device such as a personal computer. As shown in FIG. 3, the calculation device 13 includes an external interface 14, a memory unit 15, and a processor 16.

The external interface 14 is an interface that connects the arithmetic device 13 to an external device and transmits and receives signals between the arithmetic device 13 and the external device. The external devices connected to the arithmetic device 13 include the light source 11, the camera 12, and a control device that controls the operation of each part of the coating device 1 (the conveying part 3, the coating part 4, etc.).

The memory unit 15 is configured using a computer-readable storage medium such as a semiconductor memory such as a ROM or a RAM or a hard disk, and includes a program memory unit 151, an image data memory unit 152, and a threshold memory unit 153.

The program storage unit 151 stores, in addition to the operating system program and the driver program, application programs that execute various functions, various parameters used during the execution of these programs, etc. Specifically, the program storage unit 151 stores a judgment program for judging whether the state of the glue application on the application target 2 is good or bad, based on image data input from the camera 12.

The image data storage unit 152 stores image data input from the camera 12 and subjected to image processing by the image generation unit 164 described later.

The threshold memory unit 153 stores thresholds used to determine the coating state in the determination unit 167 described below. The thresholds are appropriately set according to coating conditions such as the material of the coating object 2, the product after the coating object 2 is processed, the type and concentration of glue, and the transport speed of the coating object 2, and are stored in the threshold memory unit 153 in association with these coating conditions.

The processor 16 is configured using, for example, a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit), and by reading various programs stored in the program storage unit 151, it comprehensively controls each part of the inspection unit 5 and executes various calculation processes for determining the state of glue application on the application target 2. In detail, the functional parts realized by the processor 16 include a light source control unit 161, an imaging control unit 162, an image processing unit 163, and a determination unit 167. Each of these parts may be configured by one or more processors and computer programs, or a combination thereof.

The light source control unit 161 controls the output operation of the near-infrared light in the light source 11 .
The imaging control unit 162 controls the imaging operation in the camera 12. In particular, the imaging control unit 162 causes the camera 12 to capture images at a predetermined frame rate, and controls the timing of the start and end of imaging.

The image processing unit 163 acquires image data generated by the camera 12, and based on the image data, generates multiple frame images that constitute a moving image showing the object to be coated 2, and performs a process of detecting the area where glue has been applied in the width direction of the object to be coated based on each frame image.

In detail, the image processing unit 163 includes an image generation unit 164, a binarization processing unit 165, and a blob analysis unit 166. The image generation unit 164 sequentially generates monochrome frame images based on image data input from the camera 12. The binarization processing unit 165 generates a binary image by performing binarization processing on each frame image generated by the image generation unit 164. The blob analysis unit 166 performs blob analysis on the binary image generated by the binarization processing unit 165.

The judgment unit 167 judges the state of glue application on the object to be applied 2 based on the results of the blob analysis.

In addition, the calculation device 13 may be connected to an operation input unit for inputting commands and information to the calculation device 13, a display device for displaying the judgment result by the judgment unit 167, a speaker for outputting an alarm sound based on the judgment result by the judgment unit 167, etc.

Next, the coating state inspection method according to this embodiment will be described with reference to a flow chart shown in FIG.
First, the image generating unit 164 acquires image data of a moving image sequentially generated by the camera 12 (step S101), and sequentially generates a plurality of frame images constituting the moving image (step S102).

Figure 5 is a schematic diagram of a frame image captured by near-infrared light and generated in step S102. In the frame image M1 shown in Figure 5, the areas m11, m13, and m15 (dark gray areas) where glue is applied and the areas m12 and m14 (light gray areas) where the glue has been scratched and not applied are shown in different gray tones for the predetermined glue application width W0. Note that the x direction shown in Figure 5 corresponds to the transport direction of the object 2 to be applied in the application device 1 (see Figure 2), and the y direction shown in Figure 5 corresponds to the width direction of the object 2 to be applied (same as above).

Next, the binarization processing unit 165 performs binarization processing on the frame image M1 (step S103). Fig. 6 is a schematic diagram of a binary image obtained by performing binarization processing on the frame image M1 shown in Fig. 5. As shown in Fig. 6, the areas m11, m13, and m15 in the frame image M1 where glue is applied are shown as areas m21, m23, and m25 with a brightness value of zero (black) in the binary image M2, and the areas m12 and m14 where glue is not applied are shown as areas m22 and m24 with a maximum brightness value (white) in the binary image M2.

Next, the blob analysis unit 166 performs blob analysis on the binary image M2 (step S104). In detail, the blob analysis unit 166 detects regions m21, m23, and m25 with a brightness value of zero corresponding to the regions where glue is applied from the binary image M2, measures the lengths (hereinafter also referred to as the application detection width) in the width direction (y direction) of the detected regions (hereinafter also referred to as the application detection regions) m21, m23, and m25, and calculates the total value of these application detection widths.

Figure 7 is a schematic diagram for explaining a method for measuring the coating detection width. The blob analysis unit 166 extracts coating detection regions at a predetermined position (e.g., the central position) in the x direction of the binary image M2, and measures the length of both ends of each coating detection region. For example, for the coating detection region m21, the coating detection width w1 (see Figure 7) within the region surrounded by the dashed line shown in Figure 6 is measured.

Next, the determination unit 167 determines the state of application of the glue on the application target 2 based on the application detection width measured by the blob analysis (step S105). FIG. 8 is a schematic diagram for explaining a method for determining the application state. In detail, the determination unit 167 calculates the total value of the measured application detection width, and further calculates the ratio of the total value of the application detection width to the application width of the glue set in advance. For example, in the case of the binary image M2 shown in FIG. 8, the ratio v = (w1 + w2 + w3) / W0 × 100 of the total value of the application detection widths w1, w2, and w3 of each of the application detection areas m21, m23, and 25 to the application width W0 is calculated.

The determination unit 167 then compares the calculated ratio v with the threshold value read from the threshold value storage unit 153, and determines that the coating state is good if the ratio v exceeds the threshold value, and determines that the coating state is poor if the ratio v is equal to or less than the threshold value. Here, the determination unit 167 reads in advance from the threshold value storage unit 153 a threshold value (e.g., 80%) according to the coating conditions.

If the determination unit 167 determines that the coating state is good (step S106: Yes), the process proceeds to step S109. On the other hand, if the determination unit 167 determines that the coating state is poor (step S106: No), the calculation device 13 outputs an error signal (step S107). In response to this, the control device of the coating device 1 receives the error signal from the calculation device 13 and can take measures such as stopping the conveying unit 3 to temporarily suspend the coating process, or identifying and removing the defective part of the coating target 2. In addition, the calculation device 13 may display on a display device that the coating state is poor, or may emit a warning sound.

Next, the image processing unit 163 stores the image data of the frame image for which the coating state is determined to be poor in the image data storage unit 152 (step S108). By storing the image data in this manner, it becomes possible to later investigate and analyze the coating state determined to be poor.

The calculation device 13 determines whether the coating process in the coating device 1 has been completed. If the coating process has not been completed (step S109: No), the process returns to step S101. On the other hand, if the coating process has been completed (step S109: Yes), the operation of the inspection unit 5 is terminated.

As described above, according to this embodiment, the inspection unit 5 can be configured with a simple configuration including a light source 11 that emits near-infrared rays, a camera 12 that is sensitive to near-infrared rays, and a computing device 13. Furthermore, by using near-infrared rays including a wavelength range of 800 nm to 950 nm as illumination light for the coating target 2, it becomes possible to use a camera 12 equipped with a CMOS image sensor, thereby making it possible to reduce the cost of the inspection unit 5.

In addition, according to this embodiment, the application state is determined based on a frame image obtained by capturing an image of the glue application area 2a (see Figure 2) on the glue application object 2 with the camera 12, so that even when the glue is applied to a specified width using an application means such as a brush, sponge or roller, it is possible to determine the application state over the entire glue application width.

In addition, according to this embodiment, the use of the camera 12 equipped with a CMOS image sensor enables imaging at a high frame rate. Therefore, even if the conveying speed of the coating target 2 is fast, frame images with little blur can be generated. Therefore, based on such frame images, it becomes possible to accurately and continuously determine the coating state.

In addition, according to this embodiment, since near-infrared light is used as the illumination light for the object 2 to be coated, even if the object and the glue are the same color, a monochrome frame image can be generated in which the area to which the glue is applied can be clearly identified. Therefore, by performing binarization processing and blob analysis on such a frame image, the area to which the glue is applied can be accurately detected. In other words, according to this embodiment, by using such image processing, even if a camera 12 with a low sensitivity (e.g., 30% to 40%) to the wavelength range of near-infrared light (approximately 800 nm to 950 nm) is used, the area to which the glue is applied can be accurately detected from the frame image. Therefore, according to this embodiment, it is possible to determine the state of the glue application quickly and accurately.

(Modification)
In the above embodiment, the coating state is judged to be good or bad based on one threshold value, but two or more threshold values may be used to judge the coating state in more detail. For example, a first threshold value t1 (e.g., 50%) and a second threshold value t2 (e.g., 60%) larger than the first threshold value t2 are set in advance, and the calculation device 13 is operated to notify the coating state of a defect when the ratio v of the total value of the coating detection width to the preset glue coating width becomes equal to or less than the threshold value t2. In this case, measures such as refilling glue or replacing the coating roller can be taken before the coating state becomes a completely defective state (the ratio is equal to or less than the threshold value t1), so that it is possible to suppress a decrease in the yield of the coating object 2. The notification of the coating state of a defect may be displayed on a display device, or a warning sound may be generated for the notification.

The present invention is not limited to the above-described embodiment and modified examples, and may be embodied in various other forms without departing from the spirit of the present invention. For example, the present invention may be formed by excluding some components from all components shown in the embodiment and modified examples, or may be formed by appropriately combining the components shown in the above embodiment and modified examples.

1...coating device, 2...coating object, 2a...coating area, 3...transport unit, 4...coating unit, 5...inspection unit, 11...light source, 11a...near-infrared light, 12...camera, 12a...field of view, 13...arithmetic unit, 14...external interface, 15...storage unit, 16...processor, 31...conveyor belt, 32...rotating drum, 151...program storage unit, 152...image data storage unit, 153...threshold storage unit, 161...light source control unit, 162...imaging control unit, 163...image processing unit, 164...image generation unit, 165...binarization processing unit, 166...blob analysis unit, 167...determination unit

Claims (10)

A coating state inspection device for inspecting the coating state of the glue applied to the coating object in a coating device provided with a conveying means for conveying an object to be coated in a predetermined direction and a coating means for applying glue to the transported object to be coated in a predetermined width, comprising:
a light source provided downstream of the coating means in a conveying direction of the object to be coated, the light source irradiating the object to be coated with near-infrared light having a wavelength range of 800 nm or more and 950 nm or less ;
A camera that includes a CMOS image sensor, has sensitivity to near-infrared rays including a wavelength range of 800 nm to 950 nm , and sequentially generates image data by capturing a moving image of the coating target irradiated with near-infrared rays by the light source;
an image processing unit that acquires image data generated by the camera, generates a plurality of monochrome frame images constituting a moving image showing the object to be coated based on the image data, and detects an area where glue is applied in a width direction of the object to be coated, which is a direction perpendicular to the transport direction, based on each of the plurality of frame images;
a determination unit that determines a state of glue application on the object based on the area detected by the image processing unit;
Equipped with
The image processing unit includes:
a binarization processing unit that performs a binarization process on each of the plurality of frame images to generate a binary image;
a blob analysis unit that performs blob analysis on the binary image to measure a length of the region in a width direction;
having
The determining unit determines the state of application of glue based on a ratio of a length in a width direction of the region to a preset application width of glue.
Coating condition inspection device. The coating state inspection device according to claim 1 , wherein the determination unit determines that the coating state is defective when the ratio is equal to or smaller than a predetermined threshold value. The coating state inspection device according to claim 2 , wherein the determination unit issues a notice of a defective coating state when the ratio becomes equal to or less than a second threshold value that is greater than the threshold value. 4. The coating state inspection device according to claim 1, wherein the near-infrared light emitted by the light source has a peak wavelength at least at 850 nm. 5. The coating state inspection device according to claim 1 , wherein the light source is a surface illuminator having a rectangular light emitting surface. The coating state inspection device according to any one of claims 1 to 5 , wherein the camera operates at at least 60 fps. 7. The coating state inspection device according to claim 1, wherein the transport means transports the object to be coated at a speed of at least 2 m/sec. 8. The coating state inspection device according to claim 1, wherein the coating means is configured to coat the glue on the coating object with a thickness of 100 μm or less . A coating state inspection device according to any one of claims 1 to 8 ,
The conveying means;
The coating means;
A coating device comprising: A coating state inspection method for inspecting a coating state of glue applied to an object to be coated in a coating device provided with a conveying means for conveying an object to be coated in a predetermined direction and a coating means for applying glue to the conveyed object to be coated in a predetermined width, comprising:
an irradiation step of irradiating the object with near-infrared light having a wavelength range of 800 nm or more and 950 nm or less on a downstream side of the coating means in a conveying direction of the object;
An imaging step of sequentially generating image data by capturing a moving image of the coating object irradiated with near-infrared rays from the light source using a camera having a CMOS image sensor and sensitivity to near-infrared rays including a wavelength range of 800 nm to 950 nm;
an image processing step of acquiring image data generated by the camera, generating a plurality of monochrome frame images constituting a moving image showing the object to be coated based on the image data, and detecting an area to which glue is applied in a width direction of the object to be coated, which is a direction perpendicular to the transport direction, based on each of the plurality of frame images;
a determination step of determining a state of application of glue on the object to be applied based on the area detected in the image processing step;
Including,
The image processing step includes:
generating a binary image by performing a binarization process on each of the plurality of frame images;
measuring a length of the region in a width direction by performing blob analysis on the binary image;
The determining step includes determining a state of application of glue based on a ratio of a length in a width direction of the region to a predetermined application width of glue.
Coating condition inspection method.

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