Defect Detection Device for Topping Rubber Sheet with Rubber

Abstract

To accurately detect the occurrence of even small rubber adhesion failure without missing it to stably detect the occurrence of rubber adhesion failure.SOLUTION: A device for detecting rubber adhesion failure on a topping rubber sheet comprises: image data acquisition means that acquires image data by photographing a surface of a topping rubber sheet obtained by covering a textile sheet with topping rubber; and detection means that performs image processing on the image data acquired by the image data acquisition means to detect the occurrence of rubber adhesion failure on the topping rubber sheet. The image data acquisition means includes an irradiation device that continuously irradiates the surface of the topping rubber sheet with light, and a line sensor camera that receives the light with which the irradiation device irradiates the surface of the topping rubber sheet and reflected on the surface to acquire the image data. The irradiation device and the line sensor camera are arranged such that regularly reflected light, of the reflected light, is incident on the line sensor camera, and the light with which the surface is irradiated is infrared light.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a defective rubber coating detection device for a topping rubber sheet that inspects the coating state of the topping rubber on a topping rubber sheet in which a textile sheet is coated (topped) with the topping rubber, and detects the occurrence of defective rubber coating on the topping rubber sheet.

Background Art

[0002] In the manufacture of pneumatic tires (hereinafter, also simply referred to as "tires"), a topping rubber sheet in which both sides of a textile sheet formed by weaving cord materials are coated with rubber (topping rubber) is used as a tire member such as a carcass, a belt, and a breaker.

[0003] At this time, if a state where the rubber coating on the textile sheet is insufficient (defective rubber coating) occurs, there is a risk of causing poor tire quality. Therefore, it is necessary to sufficiently inspect the coating state of the topping rubber and detect the occurrence of defective rubber coating. The inspection has been performed by visual observation of workers.

[0004] Specifically, when the rubber coating is insufficient, a part of the textile sheet is exposed from the topping rubber sheet. Therefore, the inspection has been performed by visual observation to see whether the textile sheet can be seen from above the topping rubber sheet.

[0005] However, visual observation by workers was not sufficient. Therefore, a defective rubber coating detection device for a topping rubber sheet equipped with a line sensor camera (hereinafter, also simply referred to as a "detection device") is used to irradiate light on the surface of the topping rubber sheet, take an image of the reflected light, and then process the captured image data. Various techniques have been proposed to inspect the coating state of the topping rubber from the color difference and detect the occurrence of defective rubber coating (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the above-described conventional technology, since there is almost no difference in the intensity of the reflected light from the textile sheet and the intensity of the reflected light from the surface of the topping rubber and they are equivalent, it is difficult to accurately detect a defective product with rubber of about 2 cm square or less, and there is a risk of inspection omission and inability to perform stable detection.

[0008] Therefore, an object of the present invention is to provide a rubber attachment defect detection device for a topping rubber sheet that can accurately detect the occurrence of a rubber attachment defect of about 2 cm square or less without overlooking it and can stably detect the occurrence of a rubber attachment defect.

Means for Solving the Problems

[0009] The inventor of the present invention has intensively studied to solve the above problems, and has found that the above problems can be solved by the invention described below, and has completed the present invention.

[0010] The invention according to claim 1 is a rubber attachment defect detection device for a topping rubber sheet that detects the occurrence of a rubber attachment defect in a topping rubber sheet in which a topping rubber is coated on a textile sheet, image data acquisition means for photographing the surface of the topping rubber sheet to acquire image data, detection means for performing image processing on the image data acquired by the image data acquisition means to detect the occurrence of a rubber attachment defect in the topping rubber sheet, and the image data acquisition means is An irradiation device that continuously irradiates light onto the surface of the topping rubber sheet, and a line sensor camera that receives the reflected light irradiated from the irradiation device and reflected on the surface of the topping rubber sheet to acquire image data, wherein the irradiation device and the line sensor camera are arranged such that specularly reflected light among the reflected light enters the line sensor camera, and further, the light to be irradiated is near-infrared light and detect the occurrence of defective rubber in the topping rubber sheet based on the reflection from the textile sheet and the reflection from the topping rubber characterized in that it is a defective detection device with rubber for a topping rubber sheet.

[0012] Claim 2 The invention according to claim is characterized in that the near-infrared light is near-infrared light having a wavelength of 780 to 1500 nm, according to claim 1 which is a defective detection device with rubber for a topping rubber sheet.

[0013] Claim 3 The invention according to claim is characterized in that an infrared LED is used as the irradiation source of the infrared light, according to claim 1 or Claim to 2 which is a defective detection device with rubber for a topping rubber sheet.

[0014] Claim 4 The invention according to claim is characterized in that the irradiation device is arranged such that the infrared light is irradiated at an incident angle of 5 to 45° with respect to the surface of the topping rubber sheet, according to any one of claims 1 to claim 3 which is a defective detection device with rubber for a topping rubber sheet.

[0015] Claim 5 The invention according to claim is characterized in that the irradiation device and the line sensor camera in the image data acquisition means are arranged at positions 20 to 400 mm apart in the vertical direction from the surface of the topping rubber sheet, according to any one of claims 1 to claim4 It is a rubber-attached defect detection device for a topping rubber sheet according to any one of the following claims.

[0016] Claim 6 The invention described in The image data acquisition means includes an encoder for measuring the conveyance position of the topping rubber sheet, The imaging data by the line sensor camera is acquired in synchronization with the position information by the encoder, and the rubber-attached defect detection device for a topping rubber sheet according to any one of claims 1 to 5 is characterized by this.

[0017] Claim 7 The invention described in The image processing is image processing in a shading probe mode, The detection means detects a white portion as a textile sheet portion from the obtained image processing data, and the rubber-attached defect detection device for a topping rubber sheet according to any one of claims 1 to 6 is characterized by this.

[0018] Claim 8 The invention described in Furthermore, when the area of the portion of the textile sheet detected by the detection means is equal to or greater than a predetermined threshold value, it is determined that the occurrence of a rubber-attached defect has been detected, and a warning output means for outputting a warning signal is provided, and the rubber-attached defect detection device for a topping rubber sheet according to any one of claims 1 to 7 is characterized by this.

Effect of the Invention

[0019] According to the present invention, it is possible to provide a rubber-attached defect detection device for a topping rubber sheet that can accurately detect the occurrence of a rubber-attached defect with high accuracy without missing the occurrence of a small rubber-attached defect of about 2 cm square or less, and can stably detect the occurrence of a rubber-attached defect.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0021] 1. Features of the rubber-coated defect detection device for the topping rubber sheet according to the present invention First, the features of the rubber-coated defect detection device for the topping rubber sheet according to the present invention will be described.

[0022] As described above, since the topping rubber and the textile sheet reflect the irradiated light to the same extent and there is almost no difference in the intensity of the reflected light and they are equivalent, even if an image by the reflected light is processed, it is difficult to accurately distinguish the topping rubber and the textile sheet and confirm the coating state of the topping rubber on the textile sheet.

[0023] In order to solve the above problems, the inventor came up with the idea of changing the type of light. That is, light is a kind of electromagnetic wave, and as shown in FIG. 1, it can be divided into many types of light according to the wavelength length. Conventionally, instead of the white light used for detecting the rubber-coated defect of the topping rubber, visible light of various wavelengths is used to obtain image data from the specular reflection light where the strongest reflected light is obtained, and the coating state of the topping rubber is observed. However, no matter what wavelength of visible light it is, it was not possible to sufficiently distinguish the topping rubber and the textile sheet.

[0024] Therefore, experiments were similarly conducted on infrared light with a longer wavelength. Surprisingly, when infrared light was used, the reflection from the textile sheet did not change much, while the reflection from the topping rubber became very small, indicating that the textile sheet and the topping rubber could be clearly distinguished.

[0025] Next, the inventor further conducted experiments by changing the wavelength of the infrared light and examined the infrared light with a wavelength at which the topping rubber and the textile sheet could be most clearly distinguished among infrared lights.

[0026] That is, as shown in FIG. 1, the wavelength of infrared light increases in the order of near-infrared light, mid-infrared light, and far-infrared light. As a result of the experiment, near-infrared light with a wavelength of 780 nm to 3 μm is preferable, and among them, it was found that near-infrared light with a wavelength of 780 to 1500 nm can most clearly distinguish the topping rubber and the textile sheet.

[0027] The present invention is based on the above findings. The rubber coating defect detection device for a topping rubber sheet according to the present invention is a rubber coating defect detection device for a topping rubber sheet that detects the occurrence of a rubber coating defect in a topping rubber sheet in which a textile sheet is coated with a topping rubber. The device includes an image data acquisition unit that captures an image of the surface of the topping rubber sheet to acquire image data, and a detection unit that performs image processing on the image data acquired by the image data acquisition unit to detect the occurrence of a rubber coating defect in the topping rubber sheet.

[0028] The image data acquisition unit includes an irradiation device that continuously irradiates light on the surface of the topping rubber sheet, and a line sensor camera that receives the reflected light irradiated from the irradiation device and reflected by the surface of the topping rubber sheet to acquire image data. The irradiation device and the line sensor camera are arranged so that the specularly reflected light enters the line sensor camera among the reflected lights.

[0029] And the most important thing in the present invention is that the light to be irradiated is infrared light.

[0030] By using such a defective detection device for the topping rubber sheet with rubber, as described above, while the reflection from the textile sheet does not change much, the reflection from the topping rubber can be made very small. Therefore, even a small defective part with rubber of about 2 cm square or less can be detected with high accuracy without being overlooked, and the occurrence of defective parts with rubber can be stably detected.

[0031] 2. Specific Embodiments Next, specific embodiments of the present invention will be described.

[0032] (1) Overall Configuration of the Device FIG. 2 is a schematic diagram showing an outline of the configuration of a defective detection device 1 for a topping rubber sheet with rubber (hereinafter, also simply referred to as a "detection device") according to the present embodiment. The detection device 1 includes an image data acquisition means having a line sensor camera 11 and an irradiation device 12, and a detection means (not shown). And, S is a topping rubber sheet that is conveyed from right to left on the paper surface as shown by the leftward arrow. Note that 13 is an encoder that measures the conveyance position of the topping rubber sheet S and is connected to the line sensor camera 11. Also, R1 is irradiation light, and R2 is regular reflection light.

[0033] The detection device 1 according to the present embodiment is basically the same as the conventional device in that it includes an image data acquisition means for acquiring image data of the conveyed topping rubber sheet S, and a detection means for performing image processing on the acquired image data to measure the coating state of the topping rubber and detect the occurrence of defective parts with rubber. However, as described above, it is different from the conventional device in that an infrared light LED is used as the irradiation source in the irradiation device 12 that constitutes the image data acquisition means.

[0034] (2) Image Data Acquisition Means As described above, the image data acquisition means includes the irradiation device 12 and the line sensor camera 11.

[0035] Since the line sensor camera 11 can perform continuous shooting, it can continuously acquire image data without being affected by the line speed.

[0036] And in the present embodiment, as shown in FIG. 2, an encoder 13 for measuring the position of the measurement region A for acquiring image data is provided in the image data acquisition means.

[0037] By acquiring the shooting data by the line sensor camera 11 in synchronization with the position information by the encoder 13, it is possible to eliminate the omission of image data and stably detect the occurrence of defective products with rubber.

[0038] Then, when infrared light is irradiated from obliquely above toward the measurement region A on the surface of the topping rubber sheet S from the irradiation device 12 at a predetermined incident angle θ1, the irradiated irradiation light R1 is reflected at a reflection angle θ2 of the same angle as the incident angle θ1 in the measurement region A and becomes regular reflection light R2. Note that the incident angle θ1 and the reflection angle θ2 are angles with respect to the perpendicular line from the surface of the topping rubber sheet S.

[0039] And in the present embodiment, the line sensor camera 11 is arranged on the extension of the regular reflection light R2 so that image data can be acquired. Therefore, it is possible to receive the reflected light at the highest intensity and create image data.

[0040] And as described above, infrared light, preferably near-infrared light, is used as the light to be irradiated. Specifically, infrared light (preferably near-infrared light) is irradiated onto the surface of the topping rubber sheet S from an infrared LED as an irradiation source provided in the irradiation device 12.

[0041] Thereby, as described above, since the reflection from the topping rubber can be sufficiently suppressed, when image processing is performed, the textile sheet and the topping rubber can be accurately distinguished, and the occurrence of defective products with rubber can be stably detected.

[0042] Next, if the incident angle of the irradiation light irradiated onto the surface of the topping rubber sheet is too large, there is a risk of contact with the topping rubber sheet unless the irradiation device is placed far away. On the other hand, if it is too small, the distance between the irradiation device and the line sensor camera cannot be ensured sufficiently, and there is a risk of contact with each other. Therefore, in the present embodiment, the incident angle of the irradiation light is preferably 5 to 45°, more preferably 10 to 40°, and even more preferably 15 to 35°.

[0043] In addition, infrared light also has the characteristic of being less affected by dirt on the surfaces of the irradiation device and the line sensor camera.

[0044] And the image data acquisition means (line sensor camera and irradiation device) is preferably arranged at an appropriate distance in the vertical direction from the surface of the topping rubber sheet, specifically, at a position 20 to 400 mm away. If it is too close, there is a risk of contact with the conveyed topping rubber sheet. On the other hand, if it is too far, it becomes difficult to obtain sufficient reflected light. More preferably, it is 25 to 300 mm, and even more preferably, it is 30 to 100 mm.

[0045] (3) Detection means The detection means detects the occurrence of rubber attachment defects by performing image processing on the image data acquired by the above-described image data acquisition means using an image processing device.

[0046] Specifically, for example, from the image processing data obtained by performing image processing in the light and shade probe mode, the white part is detected as the textile sheet part, and its area is obtained. Then, the area of the obtained textile sheet part is compared with a determination criterion (threshold value) incorporated in the control device in advance.

[0047] As a result of the comparison, if it is equal to or greater than the threshold value, it is determined that a rubber attachment defect has occurred, and a warning signal is issued to the operator using warning output means such as sound or light. Thus, in the present embodiment, since the occurrence of rubber attachment defects can be automatically detected accurately and stably, the burden on the operator is also reduced.

[0048] In the above description, the case where the detection device is arranged above the conveyance line has been described as an example. However, as shown in FIG. 3, the topping rubber sheet S is conveyed so as to straddle the two conveyance lines 14, 14, and between the conveyance lines 14, 14, detection devices may be arranged above and below the topping rubber sheet S to detect the occurrence of rubber attachment defects from both sides of the topping rubber sheet S. Thereby, the occurrence of rubber attachment defects can be detected more efficiently.

[0049] As described above, according to the present embodiment, even for a thick material such as a topping rubber sheet, the textile sheet and the topping rubber can be accurately distinguished, and by knowing the coating state of the topping rubber on the textile sheet, the occurrence of rubber attachment defects can be stably detected.

[0050] And, conventionally, the occurrence of rubber attachment defects, which was difficult to discover until the next process, can be discovered at the stage of manufacturing the topping rubber sheet and appropriately dealt with, so that it is possible to greatly contribute to the reduction of the occurrence of defective losses and the improvement of quality.

Example

[0051] Next, the present invention will be described more specifically based on examples.

[0052] 1. Experimental method (1) Equipment Line sensor camera: XG-HL04M manufactured by Keyence Corporation (16x speed 4000 pixel line sensor camera) Lens: CA-LHW12 manufactured by Keyence Corporation (12 mm lens for line sensor camera) Image processing device: XG-X2800 manufactured by Keyence Corporation Irradiation light source: HLND-1800SW2-RRBC manufactured by CCS, Inc.

[0053] (2) Shooting and image processing conditions The line sensor camera and the irradiation device were arranged at a position 50 mm above (in the vertical direction) the conveying line, and the line sensor camera was installed so that the specularly reflected light from the surface of the topping rubber sheet entered. Then, near-infrared light with a wavelength of 860 nm was irradiated onto the surface of the topping rubber sheet from the irradiation device at an incident angle of 30°, the specularly reflected light was received by the line sensor camera, and the captured image was sent to the image processing device. Thereafter, image processing was performed in the image processing device in the light and shade probe mode (Example).

[0054] On the other hand, for comparison, visible light was irradiated using a white LED, and in the same manner as in the example, the captured image received by the line sensor camera was sent to the image processing device and image processing was performed (Comparative Example).

[0055] 2. Experimental Results The image data obtained in the example and the comparative example are shown in FIG. 4. In FIG. 4, (a) is the comparative example and (b) is the example.

[0056] As shown in FIG. 4, in the comparative example, the reflection in the area of the upper textile sheet is also seen in the area of the topping rubber to an extent that does not vary significantly, indicating that the area of the topping rubber and the area of the textile sheet cannot be clearly distinguished.

[0057] In contrast, in the example, while the area of the textile sheet shows a clear white, the area of the topping rubber shows a clear black throughout, indicating that the two can be clearly distinguished.

[0058] As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above embodiments. Various changes can be made to the above embodiments within the same and equivalent scope as the present invention.

Explanation of Reference Numerals

[0059] 1 Detection Device 11 Line Sensor Camera 12 Irradiation Device 13 Encoder 14 Conveyor line A Measurement area S Topping rubber sheet R1 Irradiating light R2 Regular reflection light θ1 Incident angle θ2 Reflection angle

Claims

1. A rubber-coated defect detection device for a topping rubber sheet that detects the occurrence of defects with rubber in a topping rubber sheet in which a topping rubber is coated on a textile sheet, comprising: image data acquisition means for photographing the surface of the topping rubber sheet to acquire image data; detection means for performing image processing on the image data acquired by the image data acquisition means to detect the occurrence of defects with rubber in the topping rubber sheet; The image data acquisition means includes: an irradiation device that continuously irradiates light on the surface of the topping rubber sheet; a line sensor camera that receives the reflected light irradiated from the irradiation device and reflected by the surface of the topping rubber sheet to acquire image data; the irradiation device and the line sensor camera are arranged so that specularly reflected light among the reflected light enters the line sensor camera; furthermore, the light to be irradiated is near-infrared light; A rubber-coated defect detection device for a topping rubber sheet, characterized in that the occurrence of defects with rubber in the topping rubber sheet is detected based on the reflection from the textile sheet and the reflection from the topping rubber.

2. The rubber-coated defect detection device for a topping rubber sheet according to claim 1, wherein the near-infrared light is near-infrared light having a wavelength of 780 to 1500 nm.

3. The rubber-coated defect detection device for a topping rubber sheet according to claim 1 or claim 2, characterized in that an infrared LED is used as the irradiation source of the infrared light.

4. The rubber-coated defect detection device for a topping rubber sheet according to any one of claims 1 to 3, characterized in that the irradiation device is arranged so that the infrared light is irradiated on the surface of the topping rubber sheet at an incident angle of 5 to 45°.

5. The rubber-coated defect detection device for a topping rubber sheet according to any one of claims 1 to 4, characterized in that the irradiation device and the line sensor camera in the image data acquisition means are arranged at positions 20 to 400 mm apart in the vertical direction from the surface of the topping rubber sheet.

6. The image data acquisition means includes an encoder for measuring the conveyance position of the topping rubber sheet. The rubber-coated defect detection device for a topping rubber sheet according to any one of claims 1 to 5, characterized in that it is configured to acquire the imaging data by the line sensor camera in synchronization with the position information by the encoder.

7. The image processing is image processing in a density probe mode, The rubber-coated defect detection device for a topping rubber sheet according to any one of claims 1 to 6, characterized in that the detection means detects a white portion as a textile sheet portion from the obtained image processing data.

8. Furthermore, when the area of the portion of the textile sheet detected by the detection means is equal to or greater than a predetermined threshold value, it is determined that the occurrence of a rubber-coated defect has been detected, and a warning output means for outputting a warning signal is provided. The rubber-coated defect detection device for a topping rubber sheet according to any one of claims 1 to 7, characterized in that.

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