Inspection Method and Inspection Apparatus for Cylindrical Body Surface

Abstract

To provide an inspection method of a cylindrical body surface and an inspection device of the cylindrical body surface which can detect a minute defect even if the cylindrical body surface is made of a material that is transparent or close to transparent or determine the type of the detected defect.SOLUTION: An inspection method of a cylindrical body surface according to the present invention executes: a first step of irradiating a cylindrical body with light in such a state that the cylindrical body is rotated, receiving reflection light, which is the light emitted and reflected on the surface of the cylindrical body, with one-dimensional imaging means, and stopping the rotation of the cylindrical body when a defect on the surface of the cylindrical body is detected from an image captured by the one-dimensional imaging means; and a second step of irradiating the cylindrical body with light from an angle at which the irradiation angle to the surface of the cylindrical body is different from the irradiation angle of the light emitted to the surface of the cylindrical body in the first step in such a state that the cylindrical body is stopped, receiving reflection light, which is the light emitted and reflected on the surface of the cylindrical body, with two-dimensional imaging means and imaging the position of the defect detected in the first step with the two-dimensional imaging means.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for detecting defects on the surface of a cylindrical body.

Background Art

[0002] In the manufacturing process of a cylindrical body such as a rubber roller, it has been a problem that defects such as scratches and dents occur on its surface. Although the surface properties required vary depending on the use of the cylindrical body, in the case of applications that dislike scratches and dents, such as rollers for film forming, an inspection method and an inspection apparatus for inspecting the surface with high precision are required.

[0003] Conventionally, when inspecting such defects, in addition to visual inspection by human eyes, the inspection has been performed by detecting the surface of the cylindrical body by some method and determining the presence or absence of defects. For example, as in Patent Document 1, there is a technique of measuring the surface of a cylindrical body using a distance sensor, and as in Patent Document 2, there is a technique of detecting light leaking from the gap between the cylindrical body and two cylindrical bodies for measurement to confirm the presence or absence of surface unevenness.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the technologies disclosed in Patent Documents 1 and 2 have the following problems. Since Patent Document 1 uses a distance meter using laser light or the like, when the material of the surface of the cylindrical body is transparent or near-transparent, light is transmitted, and reflected light from information inside the cylindrical body surface, such as internal foreign matter, is detected, making it impossible to accurately measure the distance to the surface and resulting in a large number of false detections. Further, although Patent Document 2 detects light leakage from defective portions, this also causes light to leak from areas other than the defective portions of the cylindrical body surface when the material of the cylindrical body surface is transparent rubber or the like, making it impossible to detect unevenness.

[0006] The present invention solves the problems of the prior art, and provides a cylindrical body surface inspection apparatus and a cylindrical body inspection method capable of detecting minute defects even when the surface of the cylindrical body is made of a transparent or near-transparent material, and discriminating the types of detected defects.

Means for Solving the Problems

[0007] The inspection method for the surface of a cylindrical body of the present invention for solving the above problems is a method for inspecting the surface of a cylindrical body, comprising: In a state where the cylindrical body is rotated, irradiating the cylindrical body with light, receiving, by one-dimensional imaging means, reflected light that is the irradiated light reflected from the surface of the cylindrical body, and stopping the rotation of the cylindrical body when a defect on the surface of the cylindrical body is detected from the image captured by the one-dimensional imaging means (first step); Next, in a state where the cylindrical body is stopped, irradiating the cylindrical body with light from an angle different from the irradiation angle of the light irradiated onto the surface of the cylindrical body in the first step, receiving, by two-dimensional imaging means, reflected light that is the irradiated light reflected from the surface of the cylindrical body, and imaging the position of the defect detected in the first step with the two-dimensional imaging means (second step).

[0008] The inspection apparatus for the surface of a cylindrical body of the present invention for solving the above problems is A support mechanism that rotatably supports a cylindrical body around its axis, a light source that irradiates light onto the cylindrical body supported by the support mechanism, means for moving the light source, irradiation angle changing means capable of changing the irradiation angle of the light irradiated from the light source with respect to the surface of the cylindrical body, one-dimensional imaging means and two-dimensional imaging means, and control means. A first procedure in which the control means irradiates the cylindrical body with light from the light source while the cylindrical body is rotated by the support mechanism, receives, by the one-dimensional imaging means, the reflected light reflected from the surface of the cylindrical body by the irradiated light, and stops the support mechanism and stops the rotation of the cylindrical body when a defect on the surface of the cylindrical body is detected from the image captured by the one-dimensional imaging means. Next, in a state where the rotation of the cylindrical body is stopped, the irradiation angle changing means moves the light source so that the irradiation angle of the light irradiated from the light source with respect to the surface of the cylindrical body becomes an angle different from the irradiation angle in the first procedure, irradiates the cylindrical body with light from the light source, receives, by the two-dimensional imaging means, the reflected light reflected from the surface of the cylindrical body by the irradiated light, and performs a second procedure of imaging the position of the defect detected in the first procedure with the two-dimensional imaging means.

[0009] Another form of the inspection apparatus for the surface of a cylindrical body according to the present invention that solves the above problems is A support mechanism that rotatably supports a cylindrical body around the axis of the cylindrical body, a first light source that irradiates light onto the cylindrical body supported by the support mechanism, a second light source that irradiates light onto the cylindrical body from an angle different from the irradiation angle of the light irradiated from the first light source with respect to the surface of the cylindrical body, one-dimensional imaging means and two-dimensional imaging means, and control means. A first procedure in which the control means irradiates the cylindrical body with light from the first light source while the cylindrical body is rotated by the support mechanism, receives, by the one-dimensional imaging means, the reflected light reflected from the surface of the cylindrical body by the irradiated light, and stops the support mechanism and stops the rotation of the cylindrical body when a defect on the surface of the cylindrical body is detected from the image captured by the one-dimensional imaging means. Next, with the rotation of the above-described cylindrical body stopped, light is irradiated from the above-described second light source onto the cylindrical body, and the reflected light obtained by the irradiated light being reflected by the surface of the cylindrical body is received by the above-described two-dimensional imaging means, and a second procedure is performed to image the position of the defect detected in the above-described first procedure using the above-described two-dimensional imaging means, and control is performed such that this is done.

[0010] Note that since the cylindrical body is an object to be inspected, in the inspection apparatus for the surface of the cylindrical body of the present invention, the cylindrical body itself is not included in the configuration of the inspection apparatus.

[0011] Each term in the present invention is defined as follows. The "cylindrical body" refers to, for example, a roller used in industrial machinery or a cylindrical part before its assembly, and includes those with an axis attached to the cylindrical part. It also includes a solid cylindrical roller and its members.

[0012] The "light source" refers to a device that generates light, and examples include an LED, an organic EL, a fluorescent lamp, a halogen lamp, an HID lamp, and the like.

[0013] The "one-dimensional imaging means" refers to an element in which elements that convert the brightness of light into an electrical signal are arranged in a straight line, and generally refers to what is called a line camera or a line scan camera.

[0014] The "two-dimensional imaging means" refers to an element in which elements that convert the brightness of light into an electrical signal are arranged on a plane, and generally refers to what is called an area camera or an area scan camera, or what is called a microscope.

[0015] The "irradiation angle changing means" refers to a mechanism that supports the light source movably and can move the light source by a driving means such as a motor or an actuator.

[0016] The "control means" refers to means for controlling the operations of a light source, a one-dimensional imaging means, a two-dimensional imaging means, an irradiation angle changing means, and a support mechanism. For example, a programmable logic controller (hereinafter sometimes referred to as a PLC), a personal computer (hereinafter sometimes referred to as a PC), a smartphone, a tablet terminal, and an image processing apparatus including an electric circuit combined with these and having equivalent functions thereto.

[0017] "To stop the rotation of the cylindrical body when a defect on the surface of the cylindrical body is detected" includes not only the procedure of stopping the cylindrical body simultaneously with detecting the defect, but also the procedure of rotating the cylindrical body by a predetermined time or rotation amount after detecting the defect and then stopping it.

Advantages of the Invention

[0018] According to the method for inspecting the surface of a cylindrical body and the apparatus for inspecting the surface of a cylindrical body of the present invention, even if the surface of the cylindrical body is made of a transparent or nearly transparent material, defects can be detected.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0020] Hereinafter, examples of embodiments of the present invention will be described with reference to the drawings.

[0021] [First Embodiment] Refer to FIG. 1. FIG. 1 is a schematic view of a first embodiment of an inspection device for the surface of a cylindrical body as seen from the central axis direction of the cylindrical body. The inspection device 1a of the first embodiment (hereinafter simply referred to as "inspection device 1a") includes a support mechanism (not shown in FIG. 1) that rotatably supports the cylindrical body 2 around its axis, a light source 5 that irradiates light onto the cylindrical body 2, a one-dimensional imaging means 3 that receives the reflected light when the light irradiated by the light source 5 is reflected from the surface of the cylindrical body 2, an irradiation angle changing means (not shown) that changes the position of the light source 5, a two-dimensional imaging means 4 that receives the reflected light when the light irradiated by the changed-position light source 5' is reflected from the surface of the cylindrical body 2, and a control means (not shown) that controls the support mechanism, the light source 5 (5'), the one-dimensional imaging means 3, the two-dimensional imaging means 5, and the irradiation angle changing means.

[0022] The inspection device 1a can be applied to any cylindrical body, but is preferably used for cylindrical bodies with an outer diameter of 100 mm or more and 1000 mm or less, and a surface length of 0.5 m or more and 10 m or less. For example, it includes rollers used in papermaking equipment, plastic film forming equipment, metal rolling equipment, and post-processing equipment such as web coating and vapor deposition, as well as printing and copying equipment. In particular, by using the inspection device 1a, even for large cylindrical bodies, fine surface defects can be detected. Therefore, it can preferably detect minute surface defects of rollers used in applications where fine surface defects on the cylindrical body surface directly lead to product defects, such as in a film forming device that sandwiches and cools a thermoplastic resin between two rollers to obtain a plastic film.

[0023] The control means first controls to perform a first procedure in which, with the cylindrical body 2 rotated by the support mechanism, light is irradiated from the light source 5 onto the cylindrical body 2, the reflected light when the irradiated light is reflected from the surface of the cylindrical body 2 is received by the one-dimensional imaging means 3, and at the same time as detecting the defects on the surface of the cylindrical body 2 from the image captured by the one-dimensional imaging means 3, the support mechanism is stopped to stop the rotation of the cylindrical body 2.

[0024] Refer to FIG. 2. FIG. 2 is a schematic diagram for explaining the support mechanism. The support mechanism 6 rotatably supports and rotates the cylindrical body 2 about the rotation axis of the cylindrical body 2. The support mechanism 6 supports at least two locations of the cylindrical body 2. The method of rotatably supporting two locations is not particularly limited. For example, two units each having a shaft fitted and supported in the inner ring of a bearing are arranged to be rotatably supported, and the cylindrical body 2 is placed and supported on the outer rings of those bearings, or a bearing may be simply fitted to the shaft of the cylindrical body 2 to support the bearing. The method of rotating the cylindrical body 2 is not particularly limited. For example, a general motor such as an AC motor or a DC motor can be used, and a speed change mechanism may be provided as needed. By imaging with the one-dimensional imaging means 3 while rotating the cylindrical body 2 at a constant speed by the support mechanism 6, imaging can be performed at a constant scale with respect to the rotation direction Dr of the cylindrical body 2. Further, it is possible to prevent measurement omission from occurring due to the rotation speed being too fast and exceeding the measurable speed of the one-dimensional imaging means 3.

[0025] Refer to FIG. 1 again. The method of irradiating light by the light source 5 is not particularly limited. However, during imaging by the one-dimensional imaging means 3, it is preferable that the light source 5, the one-dimensional imaging means 3, and the relative positional relationship among the surface of the cylindrical body 2 imaged by the one-dimensional imaging means 3 do not change, so that imaging can be performed in a certain visible manner.

[0026] The relative positional relationship among the light source 5, the one-dimensional imaging means 3, and the surface of the cylindrical body 2 imaged by the one-dimensional imaging means 3 is appropriately adjusted and determined according to the surface material of the cylindrical body 2, the shape of the defect to be detected, the type of the light source, etc. In particular, when inspecting the cylindrical body 2 whose surface is a transparent or nearly transparent material, as shown in FIG. 1, imaging is performed with the one-dimensional imaging means 3 in the central axis direction of the cylindrical body 2, and the angle θ formed between the tangent direction of the surface of the cylindrical body 2 at the portion imaged by the one-dimensional imaging means 3 and the line connecting the surface portion imaged by the one-dimensional imaging means 3 and the position of the light source 5 is arranged to be 0 to 30 degrees, which is preferable because minute defects can be easily detected. Further, the one-dimensional imaging means 3 may be directed in the central axis direction of the cylindrical body 2 or may be tilted by about 0 to 10°.

[0027] The light source 5 can be appropriately selected from generally available light sources such as LEDs, organic ELs, fluorescent lamps, halogen lamps, and HID lamps. LEDs and organic ELs can be preferably used because the shape of the irradiation range and the color of the irradiated light can be changed according to the imaging means, the material of the cylindrical body 2, etc.

[0028] The one-dimensional imaging means 4 is a device in which elements (hereinafter sometimes referred to as imaging elements) that convert the brightness of light into an electrical signal are arranged in a straight line, and generally refers to what is called a line camera or a line scan camera. CCDs, CMOSs, etc. are generally used as imaging elements, and the number of elements is appropriately selected according to the required resolution and field of view. For example, when it is desired to detect a defect with a size of 100 μm or less in a field of view of 10 mm or more, the number of elements is preferably 2000 or more, and more preferably 4000 or more. Also, it is preferable to adjust the magnification and field of view using a lens suitable for the required resolution and field of view.

[0029] Defects can be detected by continuously imaging with the one-dimensional imaging means 3 while rotating the cylindrical body 2 and analyzing the obtained one-dimensional imaging data. Also, two-dimensional image data can be obtained by arranging the obtained one-dimensional imaging data, and defects can also be detected by analyzing the obtained two-dimensional image data. These can be realized, for example, by a commercially available image processing device or a computer program, but the means is not particularly limited.

[0030] Next, in a state where the rotation of the cylindrical body 2 is stopped, the control means moves the light source 5 to the position of the reference numeral 5' with the irradiation angle changing means so that the irradiation angle of the light source 5 with respect to the surface of the cylindrical body 2 irradiated from the light source 5 becomes an angle different from the irradiation angle in the first procedure, irradiates the cylindrical body 2 with light from the light source 5', receives the reflected light reflected from the surface of the cylindrical body 2 by the two-dimensional imaging means 4, and controls so as to perform a second procedure of imaging the position of the defect detected in the first procedure with the two-dimensional imaging means 4.

[0031] Incidentally, the above irradiation angle includes, in addition to the angle θ formed between the tangent direction of the surface of the cylindrical body 2 at the portion imaged by the one-dimensional imaging means 3 shown in FIG. 1 and the line connecting the surface portion imaged by the one-dimensional imaging means 3 and the position of the light source 5, the angle φ formed between the axial direction of the cylindrical body 2 around the normal line at the imaging portion on the surface of the cylindrical body 2 shown in FIG. 2 and the irradiation direction of the light from the light source 5.

[0032] The irradiation angle changing means can move the light source 5 to the position of reference numeral 5' to change the angle at which the defect on the surface of the cylindrical body 2 is irradiated with light. The irradiation angle changing means is not particularly limited, and for example, those that support the light source 5 movably and move it with a linear actuator or a servo motor can be used.

[0033] The two-dimensional imaging means 4 is composed of imaging elements arranged on a plane, and generally refers to an area camera, an area scan camera, or a microscope. As the imaging element, a CCD, a CMOS, etc. are generally used, and the number of elements is appropriately selected according to the required resolution and field of view. For example, when it is desired to detect a defect with a size of 100 μm or less in a field of view of 10 mm or more, the number of elements is preferably 2 million or more, and more preferably 4 million or more. Also, it is preferable to adjust the magnification and the field of view using a lens suitable for the required resolution and field of view.

[0034] Since imaging by the two-dimensional imaging means 4 is performed with the positional relationship between the two-dimensional imaging means 4, the defect, and the light source 5 fixed, the size of the defect can be easily measured from the obtained imaging data.

[0035] By comparing the imaging data obtained in the first procedure and the second procedure, that is, the imaging data with different irradiation angles of light with respect to the defect, it becomes easy to specify the type of defect. For example, in the case of convex defects such as protrusions and attachments and concave defects such as scratches and dents, the way the shadow moves when the irradiation angle of light is changed is different. Also, when the cylindrical body 2 is transparent or translucent, similarly, the appearance of the shadow is different between surface defects and internal defects, so it becomes possible to distinguish between them.

[0036] Also, a step of imaging using the two-dimensional imaging means 4 at the same light irradiation angle as in the first step may be added before the second step, or after the second step, a step of changing the light irradiation angle one or more times and imaging with the two-dimensional imaging means 4 may be added. Comparing the obtained imaging data enables more accurate discrimination of the type of defect, which is preferable.

[0037] The control means controls the operations of the light source 5, the one-dimensional imaging means 3, the two-dimensional imaging means 4, the irradiation angle changing means, and the support mechanism 6. The control means is not particularly limited, and for example, a PLC, a PC, a smartphone, a tablet terminal, an electric circuit combined with these, or an image processing apparatus including functions equivalent to these can be used.

[0038] In the inspection apparatus 1a, the irradiation angle changing means 5 automatically moves the position of the light source 5, but the light source 5 may also be moved manually. However, automatic control is preferable because the irradiation position by the light source 5 becomes more accurate.

[0039] In the inspection apparatus 1a, while detecting a defect in the first step, the support mechanism is stopped to stop the rotation of the cylindrical body 2. In the second step, imaging is performed with the two-dimensional imaging means 4 while irradiating with the light source 5' at a position approximately coinciding with the imaging position where imaging was performed with the one-dimensional imaging means 3. However, this method does not have to be limited. After detecting a defect in the first step, the cylindrical body 2 is rotated by a predetermined time or rotation amount and then the support mechanism is stopped. In the second step, imaging may be performed with the two-dimensional imaging means 4 while irradiating with the light source 5' at a position different from the position where the one-dimensional imaging means 3 detected the defect, that is, the position where the one-dimensional imaging means 3 was imaging.

[0040] [Second Embodiment] Refer to Fig. 3. Fig. 3 is a schematic view of a second embodiment of the inspection device for the surface of a cylindrical body of the present invention as seen from the central axis direction of the cylindrical body. The inspection device 1b of the second embodiment (hereinafter simply referred to as "inspection device 1b") is provided with a first light source 51 and a second light source 52 that irradiates light from an angle different from that of the first light source instead of the light source 5 that the inspection device 1a of the first embodiment had. Also, since the inspection device 1b does not mechanically move the light source, it may not be provided with the irradiation angle changing means that the inspection device 1a had. Therefore, since the inspection device 1b does not require the irradiation angle changing means, there is no need to control the irradiation angle changing means with the control means. The inspection device 1b has the same configuration as the inspection device 1a except for these differences.

[0041] The second light source 52 irradiates light on the cylindrical body 2 from an angle different from the irradiation angle of the light irradiated from the first light source 51 with respect to the surface of the cylindrical body 2.

[0042] The control means first controls to perform a first procedure in which, with the cylindrical body 2 rotated by the support mechanism, light is irradiated from the first light source 51 onto the surface of the cylindrical body 2, the reflected light reflected by the surface of the cylindrical body 2 of the irradiated light is received by the one-dimensional image means 3, a defect is detected from the image captured by the one-dimensional imaging means 3, and then the cylindrical body 2 is rotated by a predetermined time or rotation amount and then the support mechanism is stopped.

[0043] Next, with the rotation of the cylindrical body 2 stopped, the control means controls to perform a second procedure in which the irradiation angle with respect to the cylindrical body 2 is changed by turning off the first light source 51 and turning on the second light source 52, the reflected light reflected by the surface of the cylindrical body 2 of the irradiated light is received by the two-dimensional image means, and the two-dimensional imaging means 4 images the defective portion detected in the first procedure. If there is no problem with imaging by the two-dimensional image means 4, the first light source 51 may remain lit.

[0044] Similar to the inspection by the inspection device 1a, in the inspection by this inspection device 1b as well, by comparing the imaging data obtained in the first procedure and the second procedure, that is, the imaging data with different irradiation angles of light with respect to the defect, it becomes easy to specify the type of defect. A procedure of imaging with the two-dimensional imaging means 4 may be added before turning off the first light source 1, or a plurality of second light sources 52 may be provided, and a procedure of imaging with the two-dimensional imaging means 4 a plurality of times for each irradiation of light from each second light source may be added.

[0045] At least one second light source 52 is sufficient, but a plurality of them may be provided. For example, as shown in FIG. 3, a method of using the second light source 52 as a ring-shaped LED that can be divided and lit, dividing the irradiation part into four parts by 90 degrees each, and changing the irradiation angle by switching it can be preferably used.

[0046] In the inspection device 1b, after detecting a defect in the first procedure, the cylindrical body 2 is rotated by a predetermined time or rotation amount and then the support mechanism is stopped. In the second procedure, the location of the defect detected by the one-dimensional imaging means 3, that is, a position different from the position where the one-dimensional imaging means 3 is imaging, is imaged by the two-dimensional imaging means 4 while irradiating with the second light source 52, but this method does not have to be limited. The support mechanism may be stopped simultaneously with detecting a defect in the first procedure to stop the rotation of the cylindrical body 2, and in the second procedure, the position approximately corresponding to the imaging position where the one-dimensional imaging means 3 was imaging may be imaged by the two-dimensional imaging means 4 while irradiating with the second light source 52.

[0047] Also, in the inspection device 1b, although it is provided with two light sources, the first light source 51 and the second light source 52, the imaging parts of the one-dimensional imaging means 3 and the two-dimensional imaging means 4 may be made to coincide, and this imaging part may be irradiated with one light source that can be divided and lit. In this case, the part to be lit in the first procedure is the first light source 51, and the part to be lit in the second procedure is the second light source 52. Examples of such a light source that can be divided and lit include a ring-shaped LED light that can be divided and lit.

[0048] [Third Embodiment] Refer to FIG. 4. FIG. 4 is a schematic view of a third embodiment of the inspection device for the surface of the cylindrical body of the present invention as seen from the planar direction. The inspection device 1c of the third embodiment (hereinafter simply referred to as "inspection device 1c") is an embodiment in which the configuration of the inspection device 1b of the second embodiment is changed.

[0049] In the inspection device 1c, the imaging portions of the one-dimensional imaging means 3 and the two-dimensional imaging means 4 are made to coincide, and instead of providing two light sources, i.e., the first light source 51 and the second light source 52, the imaging portion is irradiated with one dividable light source 5 that can be divided and lit. By lighting different portions of the light source 5 in the first and second procedures, the first light source 51 is substituted at the portion lit in the first procedure, and the second light source 52 is substituted at the portion lit in the second procedure.

[0050] In the inspection device 1c, since the imaging portions of the one-dimensional imaging means 3 and the two-dimensional imaging means 4 coincide, in the first procedure, while detecting a defect, the support mechanism 6 is stopped to stop the rotation of the cylindrical body 2.

[0051] Further, the inspection device 1c is provided with a moving support mechanism 7, and since the entire inspection device 1c is fixed to the moving support mechanism 7, the entire inspection device 1c can be moved parallel to the central axis of the cylindrical body 2. By moving the inspection device 1c parallel to the rotation axis of the cylindrical body 2 by the moving support mechanism 7 while rotating the cylindrical body 2, the inspection device 1c can scan the surface of the cylindrical body 2 obliquely with respect to the rotation direction Dr of the cylindrical body 2, and it becomes possible to smoothly inspect the entire surface of the cylindrical body 2. Further, since the moving support mechanism 7 is also provided with a mechanism that moves in conjunction with the rotation angle of the cylindrical body 2, by making the imaging mechanism 7 advance by a distance equal to or less than the measurement range in the direction Dp of the rotation axis of the cylindrical body 2 of the one-dimensional imaging means 3 in a direction parallel to the rotation axis of the cylindrical body 2 while the cylindrical body 2 makes one rotation, it is possible to measure the entire surface of the cylindrical body 2 without omission. As the moving support mechanism 7, a commercially available linear guide, linear actuator, combination of linear bearing and shaft, and rack and pinion, ball screw, etc. can be preferably used.

[0052] [Others] In inspection devices 1a, 1b, and 1c, the cylindrical body 2 is rotated automatically by the support mechanism 6. However, both ends of the cylindrical body 2 may be supported by a rotatable support method such as bearings and rotated manually. However, since imaging can be performed at a certain scale by rotating at a constant speed, it is preferable to rotate by a driving means, and the labor required for rotation can also be reduced.

Embodiment

[0053] Using the inspection device 1c shown in FIG. 4, a surface inspection of a roller having an outer diameter of 300 mm, a surface length of 2 m, and a surface material of transparent silicone rubber as the cylindrical body 2 was performed. As the one-dimensional imaging means 3, a line camera (XG-HL04M) manufactured by Keyence was used, and as the two-dimensional imaging means 4, a digital microscope (Dino-Lite Edge AMR) manufactured by ANMO was used. A ring-shaped LED light was used as the light source 5. When the one-dimensional imaging means 3 performs imaging, 1 / 4 of the circumference is lit, and the portion where the one-dimensional imaging means 3 is imaging the surface of the cylindrical body 2 in the tangential direction of the surface of the cylindrical body 2 and the angle θ formed by the line connecting the position of the one-dimensional imaging means 3 and the light source 5 is 10 degrees, and the cylindrical body 2 is arranged so that the angle φ formed by the axial direction of the cylindrical body 2 around the normal line in the imaging portion of the surface of the cylindrical body 2 and the irradiation direction of the light of the light source 5 is 90 degrees. During shooting with the one-dimensional imaging means 3, the rotation speed of the roller was set to 2 rpm, and the moving support mechanism 7 was set to move 15 mm parallel to the axial direction of the cylindrical body 2 while the cylindrical body 2 made one rotation. The measurement results of the one-dimensional imaging means 3 were aligned by a computer program to obtain a planar image, and the portions that were bright regions in the image were determined and detected as defects. Simultaneously with the detection, the rotation of the cylindrical body 2 and the parallel movement by the moving support mechanism 7 were stopped, and the defects were imaged using the two-dimensional imaging means 4. At this time, 1 / 4 of the circumference of the ring-shaped LED was lit and switched, and the angle φ formed by the axial direction of the cylindrical body 2 around the normal line in the imaging portion of the surface of the cylindrical body 2 and the irradiation direction of the light of the light source 5 was changed by 90 degrees each time, and a total of 4 images were taken for one defect.

[0054] Four images were checked for each defect, and those with a shadow extending inside the defect were determined and classified as scratches or dents, those with a shadow extending outside the defect were determined and classified as protrusions or foreign attachments, and those with almost no visible shadow were determined and classified as internal foreign objects. On the other hand, the features of the defects were not clear from the images of the one-dimensional imaging means 3, and the defects could not be determined.

[0055] Next, as a confirmation, each defective part of the silicone rubber roller was cut out and observed with a laser microscope (LEXT OLS4000) manufactured by Olympus, and the types of defects were specified. As a result, correct determination was made for 14 out of the 15 detected defects.

Industrial Applicability

[0056] The present invention is not limited to a cylindrical surface shape measuring device for measuring industrial rollers such as film-forming rollers, but can also be applied to measuring devices for measuring rollers used in consumer devices such as printers, etc., but the scope of its application is not limited to these.

Explanation of Signs

[0057] 1a, 1b, 1c Inspection devices for the surface of the cylindrical body 2 Cylindrical body 3 One-dimensional imaging means 4 Two-dimensional imaging means 5, 5’ Light sources 51 First light source 52 Second light source 6 Support mechanism 7 Moving support mechanism Dr Rotation direction of the cylindrical body Dp Cylindrical body central axis direction θ Angle between the tangent of the cylindrical body and the light irradiation direction φ Angle between the axis of the cylindrical body and the light irradiation direction

Claims

1. A method for inspecting the surface of a cylindrical body, comprising: rotating the cylindrical body; irradiating the cylindrical body with light; receiving, by one-dimensional imaging means, the reflected light reflected from the surface of the cylindrical body by the irradiated light; a first procedure of stopping the rotation of the cylindrical body when a defect on the surface of the cylindrical body is detected from the image captured by the one-dimensional imaging means; then, with the cylindrical body stopped, irradiating the cylindrical body with light from an angle different from the irradiation angle of the light irradiated onto the surface of the cylindrical body in the first procedure; receiving, by two-dimensional imaging means, the reflected light reflected from the surface of the cylindrical body by the irradiated light; a second procedure of imaging, by the two-dimensional imaging means, the position of the defect detected in the first procedure; A method for inspecting the surface of a cylindrical body, which performs the above steps.

2. An apparatus for inspecting the surface of a cylindrical body, comprising: a support mechanism for rotatably supporting the cylindrical body around the axis of the cylindrical body; a light source for irradiating the cylindrical body supported by the support mechanism with light; means for moving the light source, which is irradiation angle changing means capable of changing the irradiation angle of the light irradiated from the light source with respect to the surface of the cylindrical body; one-dimensional imaging means and two-dimensional imaging means; control means, wherein the control means irradiates the cylindrical body with light from the light source while rotating the cylindrical body by the support mechanism, receives, by the one-dimensional imaging means, the reflected light reflected from the surface of the cylindrical body by the irradiated light, and stops the support mechanism to stop the rotation of the cylindrical body when a defect on the surface of the cylindrical body is detected from the image captured by the one-dimensional imaging means (a first procedure); then, with the rotation of the cylindrical body stopped, moves the light source by the irradiation angle changing means so that the irradiation angle of the light irradiated from the light source with respect to the surface of the cylindrical body is different from the irradiation angle in the first procedure, irradiates the cylindrical body with light from the light source, receives, by the two-dimensional imaging means, the reflected light reflected from the surface of the cylindrical body by the irradiated light, and images, by the two-dimensional imaging means, the position of the defect detected in the first procedure (a second procedure); and controls to perform the above steps. An apparatus for inspecting the surface of a cylindrical body.

3. An apparatus for inspecting the surface of a cylindrical body, comprising: a support mechanism for rotatably supporting the cylindrical body around the axis of the cylindrical body; a first light source for irradiating the cylindrical body supported by the support mechanism with light; A second light source that irradiates the cylindrical body with light from an angle different from the irradiation angle of the light irradiated from the first light source with respect to the surface of the cylindrical body, One-dimensional imaging means and two-dimensional imaging means, Control means, and The control means In a state where the cylindrical body is rotated by the support mechanism, irradiate the cylindrical body with light from the first light source, receive the reflected light reflected by the surface of the cylindrical body by the one-dimensional imaging means, and detect a defect on the surface of the cylindrical body from the image captured by the one-dimensional imaging means. A first procedure for stopping the support mechanism and stopping the rotation of the cylindrical body; Next, in a state where the rotation of the cylindrical body is stopped, irradiate the cylindrical body with light from the second light source, receive the reflected light reflected by the surface of the cylindrical body by the two-dimensional imaging means, and image the position of the defect detected in the first procedure with the two-dimensional imaging means. A second procedure; Control to perform An inspection device for the surface of a cylindrical body.

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