JP2009115468A - Inspection device and inspection method of leather - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method capable of heightening accuracy of detection of a defect such as a flaw existing on a leather surface. <P>SOLUTION: In an inspection device etc. for leather having a means for exposing an inherent defect so as to become visually recognizable by extending the leather, a leather sheet is extended at a fixed extension rate so that an inspection condition is stabilized, and a prescribed domain surface which is an inspection domain is irradiated at an angle not less than 5 degrees and below 90 degrees by a light source. A bright part hit by a beam and a part hardly hit by the beam are generated on a recessed or projecting part caused by a flaw or the like by light irradiation at the angle, and discovery of the flaw or the like is facilitated by a brightness difference (contrast) generated resultantly. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a leather inspection apparatus and inspection method.

In recent years, animal leather has been widely used as a skin material for sofas and passenger car seats. In particular, since those used for sofas and passenger car seats have large cutting dimensions, cow leather having a large body surface area is often used.
Cow leather has scratches caused by various factors. Such leather scratches include so-called natural marks caused by contact with barbed wire or insect bites during grazing, artificial wounds such as brand marks indicating the owner of livestock, damage during storage after slaughter (rot , Flies larvae).
The leather sheet just before being cut and sewn as a specific product is subjected to buffing, embossing, painting, etc. on the leather surface after tanning, and fine scratches existing on the leather surface are not noticeable. However, at the sewing stage, the leather is sewn while pulling the leather, so there are cases where scratches that have been lost to the heels and embossing that are not usually noticeable become noticeable, or scratches that have been overlooked are newly discovered. In particular, leather used for automobile handles and seats is used in a tightly stretched state, so that scratches that could not be found by prior inspection may be found after commercialization.

Further, as a method for detecting flaws in leather, X-rays, ultraviolet rays, visible rays, infrared rays, etc. are irradiated to detect the reflected waves, and this detection data is processed by an image processing means to automatically detect flaws. A method is known (Patent Document 1).
The method for detecting flaws on leather detects reflected light (reflected waves) on the leather surface by image processing. However, simple detection of reflected light does not reveal unless it is buried in leather folds. Is difficult to find.
JP-A-3-71047

As described above, some scratches on the surface of the leather can be recognized only by stretching the leather. In addition, even if the leather is stretched, there is a problem that the presence of scratches and deposits is not clear and is difficult to detect.
The present invention has been invented in view of the above problems, and provides an inspection apparatus and an inspection method that can reduce oversight of a flaw on the leather surface.

In order to solve the above problems, the present invention has the following means.
In other words, the present invention has a stretching means that stretches the leather sheet at a set elongation rate, and one or more light sources that illuminate a predetermined area on the surface of the leather sheet stretched by the stretching means.
The stretching means is a means for applying tension to the leather sheet to stretch the leather sheet, and reveals inherent defects so that the leather sheet can be visually recognized. Further, the leather sheet is stretched at a constant elongation rate so that the inspection conditions are stabilized. The elongation rate may be unique for each apparatus or may be arbitrarily changed.
The predetermined area illuminated by the light source is an inspection area to be inspected. Examples of the light source include a light bulb that emits visible light, a fluorescent light as a rod-shaped light source, and a plurality of LEDs arranged. The number of light sources does not necessarily mean the number of light bulbs or fluorescent lamps to be used. If a plurality of light sources are used to irradiate light from substantially the same direction, the number of light sources is counted as one light source. Is.
Further, the invention of the present application is characterized in that an irradiation angle of light for irradiating a predetermined area as an inspection area is set to an angle of 5 degrees or more and less than 90 degrees with respect to a surface of the predetermined area. This does not irradiate light perpendicularly to the surface of the inspection area, but irradiates light from an oblique direction to produce bright portions where light rays hit the dents and convexities caused by scratches and portions where light rays are difficult to hit. This is because a contrast difference is produced.
In addition, when the light irradiation angle is further set to be in the range of 5 to 45 degrees, the inspection apparatus can easily produce a difference in brightness and obtain a stable inspection result.

Moreover, in order to solve the said subject, the other means which concerns on this invention has the following structures. That is, it has a stretching means for stretching the leather sheet at a set elongation rate, and two rod-like light sources that illuminate a predetermined area on the surface of the leather sheet stretched by the stretching means. The two light sources are set such that the light irradiation angle with respect to the surface of the predetermined region is in the range of 5 degrees to 45 degrees, respectively, and the main irradiation directions of both light sources are 90 degrees to 45 degrees. They are arranged at different angles within the range.
The reason why the two light sources are arranged in different directions is that the shape of the defect is not uniform, and even if it is a defect that is not conspicuous from one direction, the defect is caused by irradiating light from different directions. It is intended to facilitate the discovery of

  The inspection apparatus using the two light sources can selectively light one of the two light sources according to the color of the leather to be inspected. The reflectance of light varies depending on the color. When strong light is applied to leather with a high reflectance color, the contrast due to the defect is difficult to distinguish, and even when weak light is applied to leather with a low reflectance color, it depends on the defect. Contrast is difficult to distinguish. Considering this point, in order to reduce the amount of light for white or beige leather with a high reflectance, use one light source, and for leather with a low reflectance such as black to increase the amount of light. There are two light sources.

Moreover, in order to solve the said subject, the inspection method which concerns on this invention has the following structures. That is,
The leather sheet is stretched at a set elongation rate, and a predetermined area on the surface of the stretched leather sheet is illuminated by a light source so that an irradiation angle is 5 degrees or more and less than 90 degrees with respect to the surface of the predetermined area, and exists in the predetermined area The present invention is characterized in that defects such as scratches and adhesion of deposits are found by a difference in brightness between a bright portion illuminated by the light source and a dark portion caused by the defect.

Furthermore, in order to solve the said subject, the inspection method which concerns on this invention has the following structures. That is,
The leather sheet is stretched at a set elongation rate, and both or one of two rod-shaped light sources arranged so that a predetermined area on the surface of the stretched leather sheet is 90 degrees to 45 degrees as a main irradiation direction. Is selectively used to illuminate the surface of the predetermined area with an irradiation angle of 5 degrees or more and less than 90 degrees, and defects such as flaws and deposits on the predetermined area are removed from the light source. It is characterized in that it is found by a difference in brightness between a bright part illuminated by the dark part and a dark part caused by the defect. The light source can be selected according to the color of the leather to be inspected.

The leather inspection device and method according to the present invention stretches the leather itself and inspects for the presence or absence of defects, so that it is easy to detect defects that do not appear on the surface that are difficult to detect at no load. .
In addition, since the light from the light source is irradiated from an oblique direction with respect to the inspection surface, the unevenness of the defect causes bright and dark parts of the light, and the difference in brightness makes it easy to find the defect. It has the effect that it can be done.
Furthermore, by using two light sources having different irradiation directions simultaneously or selectively, it is possible to easily find a defect even if the defect is difficult to detect with only one light source.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an appearance of an inspection apparatus 1 according to the present embodiment. 2A and 2B show the appearance of the inspection apparatus 1. FIG. 2A is a front view, FIG. 2B is a left side view, and FIG. 2C is a plan view (top view). In addition, the description about the direction and arrangement of front / rear (back), left / right, up / down, etc. in the specification is based on the front view shown in FIG. 2 (a) unless otherwise specified. Is.

  This will be described in detail below. The said inspection apparatus 1 is an apparatus which detects the fault which becomes the factor of product quality fall, such as a crack | wound and garbage which exist in the leather sheet | seat surface, by human vision. The inspection apparatus 1 is configured by mounting each means for performing leather inspection on a steel frame frame 2 having an outer shape of about 1500 mm in width, about 500 mm in depth, and about 2000 mm in height. The main means mounted on the gantry frame 2 are fixing means (first clamp 3 and second clamp 4) for fixing the sheet-like leather, stretching means 5 for generating a predetermined tension on the fixed leather, Illuminating means (first illumination 6, second illumination 7) as a light source for illuminating the leather surface. In addition, the gantry frame 2 is provided with pneumatic control equipment, piping, wiring for lighting means, switches and the like for driving the cylinder, but the description thereof is omitted.

The first clamp 3 as the fixing means includes a highly rigid metal clamp bar 8 having a narrow pressing surface formed in a length over almost the entire width of the inspection apparatus 1, and the pressing surface of the clamping bar 8. Is formed by a highly rigid pressure-receiving member 9 having a narrow pressure-receiving surface disposed so as to oppose. Contact pads 12 and 13 formed of a foaming synthetic resin material having a softness that does not damage leather are adhered to the pressing surface 10 of the clamp bar 8 and the pressure receiving surface 11 of the pressure receiving member 9. .
The pressure receiving member 9 is firmly fixed to the gantry frame 2. Further, guide poles 14, 14 projecting upward are provided at both ends of the pressure receiving member 9, and the guide cylinders 15, 15 are fixed to the both ends of the clamp bar 8. The clamp bar 8 moves in parallel with the pressure receiving member 9 by being inserted. The left and right ends of the clamp bar 8 are connected to the piston tips of air cylinders 16 and 16 fixed to the side surface of the gantry frame 2, and the clamp bar 8 moves up and down by driving the cylinders 16 and 16.

  The first clamp 3 is provided on the back side above the gantry frame 2, and after the leather sheet to be inspected is inserted between the clamp bar 8 and the pressure receiving member 9 from the gantry frame 2 back side, The leather sheet is sandwiched by driving the cylinders 16 and 16. At this time, the contact pad 12 and the contact pad 13 provided on the clamp bar 8 and the pressure-receiving member 9 are in close contact with the leather over the entire longitudinal direction of the clamp bar 8, so that the leather is prevented from moving and clamped. The occurrence of scratches is prevented.

Further, the second clamp 4 as the fixing means includes a highly rigid metal clamp bar 20 having a narrow pressing surface 21 formed to have a length almost covering the entire width of the inspection apparatus 1, and the clamp bar 20. It is comprised by the pressure receiving surface 22 arrange | positioned so that the pressing surface 21 may be opposed. The pressure receiving surface 22 is arranged in the vicinity of the middle stage on the front side of the gantry frame 2.
It is provided on the horizontal frame which comprises some.
Contact pads 23 and 24 formed of a foaming synthetic resin material having a softness that does not damage leather are adhered to the pressing surface 21 of the clamp bar 20 and the pressure receiving surface 22 on the frame. .
Guide poles 25, 25 projecting toward the front side are provided at both ends of the pressure receiving surface 22, and the clamp bars 20 are guided by the guide poles 25, 25 so as to translate in the front-rear direction. Yes.
Both ends of the clamp bar 20 are connected to piston tips of air cylinders 26 and 26 fixed to the side surface of the gantry frame 2, and the clamp bar 20 moves back and forth by driving the cylinders 26 and 26.

  As described above, the second clamp 4 is disposed in the vicinity of the middle stage on the front side of the gantry frame 2, and the leather sheet to be inspected is inserted between the clamp bar 20 and the pressure receiving surface 22, and the air cylinder 26, By driving 26, the leather sheet is sandwiched. Since the abutting pad 23 and the abutting pad 24 are provided on the clamp bar 20 and the pressure receiving surface 22, respectively, the leather is in close contact with the leather over the entire longitudinal direction of the clamp bar 20 when the leather is sandwiched. Is prevented, and the occurrence of scratches due to clamping is prevented.

A protective bar 27 having an arcuate surface shape is attached to the upper surface side of the horizontal frame provided with the pressure receiving surface 22 over almost the entire width of the gantry frame 2. The protective bar 27 has a function of protecting the leather from being damaged by a guide for facilitating the guidance of the leather sheet with respect to the second clamp 4 and a corner of the horizontal frame which is a steel frame provided with the pressure receiving surface 22. It is a member.
The clamp bar 20 is provided with a cover 28 that covers a portion other than the pressing surface 21 of the clamp bar 20 in a cylindrical shape. Since the clamp bar 20 is provided on the front surface portion of the gantry frame 2, there are many opportunities to contact the operator. Further, the cylinder 28 is moved back and forth by driving the cylinders 26, and the operator may be pushed by the operation of the clamp bar 20, so the cover 28 is provided to protect the operator.
The first clamp 3 and the second clamp 4 described above are arranged so that their longitudinal directions (left and right directions) are parallel to each other, and hold a certain region of the leather seat in parallel at the front and rear. It is like that.

A push-up member 30 serving as a leather sheet extending means 5 is provided at a substantially intermediate position between the first clamp 3 and the second clamp 4 arranged in parallel. The push-up member 30 has a curved surface 31 curved in the front-rear direction on the upper surface, and the substantially center of the leather sheet held in parallel by the first clamp 3 and the second clamp 4 by the curved surface 31 from the back surface. The leather is stretched when pushed up.
The push-up member 30 has an arcuate bulge on the front side and a cross-sectional shape provided with an inclined surface that gently descends toward the back side with the apex of the bulge being the highest position. The bottom surface is flat, and has two pivot points 32 supported by the gantry frame 2 at two locations on the back side of the bottom surface. As the push-up member 30 rotates around the rotation fulcrum 32, the front side (the arcuate bulging portion) moves up and down.

The piston tip of the air cylinder 33 attached to the gantry frame 2 is attached to two locations on the front side of the bottom surface of the push-up member 30, and the push-up member 30 is rotated by driving the air cylinder 33. . The leather sheet fixed to the first clamp 3 and the second clamp 4 is pushed upward from the back side by the rotation of the push-up member 30, and tension is applied to the leather surface to stretch it. Further, the push-up member 30 has rigidity capable of withstanding the push-up, and the curved surface 31 in contact with the leather is configured as a smooth surface so that the leather sheet is easy to slide.
As will be described in detail later, an area extending from the bulging portion of the push-up member 30 to the second clamp 4 is mainly an inspection target area (hereinafter referred to as “inspection area”).

On the uppermost part of the gantry frame 2, an illumination holding frame 40 is provided for attaching illumination means that serves as a light source. In the present embodiment, a first illumination 6 that is one of the light sources and a second illumination 7 that is another light source are fixed to the illumination holding frame 40. Both the first illumination 6 and the second illumination 7 are light sources in which directivity is given to the light emitted from the two fluorescent tubes by the reflector (hood).
The first illumination 6 is disposed at a position that illuminates the examination area in the irradiation direction along the leather extending direction in a state where the first illumination 6 is attached to the illumination holding frame 40, and the illuminance on the surface of the examination area is about 1500 to 2000 lux. It has been adjusted to be. If the illuminance is too bright, a dim filter made of white paper or the like can be attached to the surface to reduce the illuminance.
In the present embodiment, the light irradiation direction when a fluorescent tube is used means a direction orthogonal to the longitudinal direction of the fluorescent tube in a broad sense, and in a narrow sense, directivity is given by a hood. It refers to the direction of the applied light beam.

The second illumination 7 is also a light source having the same specifications as the first illumination 6. The second illumination 7 is also fixed to the illumination holding frame 40, but the direction of light irradiation to the inspection area is different from that of the first illumination 6.
Specifically, the light illumination direction of the first illumination 6 is the same as the leather extension direction, whereas the light illumination direction of the second illumination 7 is about 90 degrees with respect to the leather extension direction. It is tilted within an angle range of about 45 degrees. Describing in terms of the direction of the fluorescent lamp, the fluorescent lamp used for the first illumination 6 is arranged at an angle (λ1) orthogonal to the leather extension direction, whereas the fluorescent lamp used for the second illumination 7 is used. Are arranged inclining at an angle (λ2) in the range of about 45 degrees parallel to or parallel to the direction of leather extension (see FIG. 4).
In the case of the present embodiment, the second illumination 7 is provided with an inclination of about 10 degrees in the depth direction so as not to collide with the first illumination 6, and further, the direction of the hood so that the light efficiently illuminates the inspection area. Is adjusted so that the irradiation direction faces the inspection region.

  The lighting and extinguishing of the first illumination 6 and the second illumination 7 can be independently controlled by two switches (not shown) provided correspondingly. That is, both the first illumination 6 and the second illumination 7 are turned on, the first illumination 6 is lit and the second illumination 7 is turned off, the first illumination 6 is turned off and the second illumination 7 is turned on. The combination of can be made different.

A four-wavelength fluorescent lamp with an average color rendering index of Ra94 and a color temperature of 5500K is used as the fluorescent tube of the light source.
Ra evaluates the light of the fluorescent tube when sunlight is set to 100. The closer to 100, the closer to sunlight. In addition, light having a color temperature of 5000K to 6000K is sunlight called daytime white in clear weather, and is a light that allows human vision to feel the object as a natural hue. By using the fluorescent tube, the object can be seen in a color closer to natural color in an environment closer to sunlight, and the burden on the user's eyes can be reduced.
As equivalent to the above four-wavelength fluorescent lamp, color temperature 6700K, average color rendering index Ra84 3
A wavelength fluorescent lamp may be substituted.
Light with a color temperature of 6000K to 7000K is pale sunlight near noon, and is a light in which the color difference of the object appears strongly. The fluorescent tube is slightly inferior in natural light compared to the fluorescent tube, but it is easy to distinguish the difference in color and brightness between the scratches and other parts.

As described above, the leather sheet to be inspected is passed through the first clamp 3 from the back side of the gantry frame 2, passed over the push-up member 30, passed through the second clamp 4, and fixed. Yes. When the inspection of the inspection area is completed, the leather sheet is fed by about 20 cm in the direction from the first clamp 3 to the second clamp 4 and the work of sequentially inspecting the replaced inspection area is repeated.
The leather portion before being inserted through the first clamp 3 hangs down from the portion of the first clamp 3 at the back surface portion of the gantry frame 2. The suspended portion is guided by a guide frame 50 provided on the back surface of the gantry frame 2, guided to the guide plate 51 inside the gantry frame 2, and further, a portion that cannot be ridden on the guide plate 51 is located in front of the gantry frame 2. It hangs downward from the opening 52.

Each of the drawings shown in FIGS. 3A to 3C is a cross-sectional view of the vicinity of the left and right center of the inspection apparatus 1 as viewed from the left side. The leather inspection method by the inspection device 1 will be described with reference to FIG. FIG. 3A shows a state in which the first clamp 3 and the second clamp 4 are opened and the leading end portion of the leather sheet K is inserted through the first clamp 3 and the second clamp 4. The remaining portion of the leather sheet K is guided to a guide plate 51 in the inspection apparatus 1 by a guide frame 50 provided on the back surface of the inspection apparatus 1. The portion that cannot be fully covered with the guide frame 50 hangs downward from the front surface of the inspection apparatus 1.
The inspection area is a range of about 20 to 30 cm from the top of the push-up member 30 to the second clamp 4, and after the leather sheet K is disposed at an appropriate position, the first clamp 3 and the second clamp 4 are closed. FIG. 3B shows a state in which the first clamp 3 and the second clamp 4 are closed and the leather sheet K is sandwiched. The first clamp 3 and the second clamp 4 are operated by an air cylinder driven by air pressure, and are operated by operation of a manual switch (not shown) linked with a control valve.

  Next, the push-up member 30 is pushed up while the first clamp 3 and the second clamp 4 are closed. The push-up member 30 is a means for pushing up and stretching the leather sheet clamped at both ends. In this embodiment, the push-up member 30 is set so that the elongation rate is 0.2% (the length of 10 cm is stretched to 10.2 cm). ing. FIG. 3C shows a state in which the vicinity of the center of the region sandwiched between the first clamp 3 and the second clamp 4 is pushed up by the push-up member 30 and the leather sheet K is stretched. The push-up member 30 is also operated by an air cylinder driven by air pressure, and is operated by operation of a foot switch (not shown) linked with the control valve.

In the state in which the leather sheet K shown in FIG. 3C is stretched, both or one of the first illumination 6 and the second illumination 7 is turned on to illuminate the inspection area of the leather sheet K, and the inspection area is visually observed. Observe by. Irradiation light from the first illumination 6 and the second illumination 7 is incident at an angle that is transverse to the surface (inspection surface) of the inspection region.
The inventor makes the illuminance (lux) variable (1400, 1500, 1700, 1900), respectively, in the case where the irradiation angle of the light source with respect to the inspection surface is 35 degrees, 40 degrees, 60 degrees, and 90 degrees, so that the defect can be easily seen. An experiment was conducted to confirm the above. As a result, it was found that defects are easily detected when the irradiation angle with respect to the inspection surface is approximately 35 to 40 degrees. Therefore, it can be said that the light irradiation angle with respect to the inspection surface is ideally 35 degrees to 40 degrees if it is possible in the structure of the apparatus. In addition, the fact that the incident angle is larger than the above-mentioned angle means that the shadows caused by the irregularities of the defects are reduced, so that the irradiation angle with respect to the inspection surface is desirably 40 degrees or less. Furthermore, if the incident angle is close to 0 degrees, the amount of light reflected from the inspection surface toward the normal line is reduced, and it becomes difficult to confirm the defect, so an incident angle of at least 5 degrees or more is required.

Next, the positional relationship between the first illumination 6 and the second illumination 7 with respect to the inspection region S of the leather sheet K will be described with reference to FIG. FIG. 4A shows a state in which the inspection region S, which is one region of the leather sheet K, is viewed from the normal direction as a front view. The visual inspection is performed by viewing the inspection region S from the normal direction. T represents the direction of tension acting on the leather sheet K. The first illumination 6 and the second illumination 7 are simply represented as a single rod-shaped light source, and a direction (arrow direction) perpendicular to the longitudinal direction of each light source is represented as a light irradiation direction.
As shown in FIG. 4A, the first illumination 6 is arranged at an angle λ1 substantially orthogonal to the tension direction T of the leather sheet K, and the second illumination 7 is arranged at an angle λ2 ( 40 degrees). The angle λ2 is set to an optimum angle in the range of 0 degrees to 45 degrees.

  FIG. 4B is a left side view when FIG. 4A is a front view, and shows a state in which light from the first illumination 6 is incident on the surface of the inspection region S obliquely. . The position of the 1st illumination 6 which can provide a suitable light ray as a test | inspection light source is the range shown by h1-h2. That is, the position of the first illumination 6 is h1 to h2 so that the smallest angle α1 formed between the inspection region S and the light beam is 5 degrees or more, and the largest angle α2 formed between the inspection region S and the light beam is 45 degrees or less. It is set within the range of. The position of the first illumination 6 may be movable so that it can be moved to an optimal position as appropriate. In addition, as described above, the angle at which defects are easily found is approximately 35 degrees to 40 degrees. However, in the present embodiment, the angle α2 is set to 45 degrees so that the defects cannot be found immediately after exceeding 40 degrees. The reason is that defects can be effectively detected up to about half of the most inappropriate angle of 90 degrees.

  FIG. 4C is a side view of FIG. 4A viewed from the longitudinal direction side of the second illumination 7, and the light of the second illumination 7 is incident on the surface of the inspection region S obliquely. It represents the state of being. The position of the 2nd illumination 7 which can provide a suitable light ray as a test | inspection light source is the range shown by h3-h4. That is, the position of the second illumination 7 is h3 to h4 so that the smallest angle α3 formed between the inspection region S and the light beam is 5 degrees or more, and the largest angle α4 formed between the inspection region S and the light beam is 45 degrees or less. Is set within the range. The position of the second illumination 7 may be movable so that it can be moved to an optimal position as appropriate. The reason why the upper limit of the angle α4 is set to 45 degrees is due to the same reason as that of the first illumination 6.

  When the 1st illumination 6 and the 2nd illumination 7 are arrange | positioned as mentioned above, the fluorescent lamps which are light sources may collide with each other (interfere). In that case, mutual interference is avoided by inclining both or one of the first illumination 6 and the second illumination 7 while maintaining the irradiation direction of the light beam shown in FIG. At this time, it is desirable that each part in the longitudinal direction of the first illumination 6 is located in the range indicated by h1 to h2 described above, and each part in the longitudinal direction on the second illumination 7 is h3 to h4 described above. It is desirable to be located within the range indicated by. By maintaining the conditions, the irradiation angle of each light source with respect to the inspection region S can be maintained at an appropriate angle.

Next, the types of defects existing on the leather surface and typical examples of defect detection will be described. The shortcomings of leather include the so-called natural marks that occur during the survival of cattle such as barakis, open scratches, grabs, pinholes, silver floats, tiger wrinkles, blood lines, ticks, brands (baked seals), and so on. There are artificial scratches that occur in the leather sheet collection and processing stages.
“Barakizu” refers to a completely healed scar that has been clearly discriminated even when it becomes leather among the completely healed scars caused by rubbing against the barbed wire or standing trees around the ranch. “Open scratch” means: barbed wire, trauma caused by rubbing the body against a standing tree, and an open wound that is indented without completely healing, or is dragged when the ground is dragged after slaughter An open wound. “Grubb” refers to a hole that penetrates from the subcutaneous to the surface caused by the infestation of cattle fly larvae (maggots). Cattle fly larvae parasitize mainly on the back of cattle, but can also infest during raw hide storage. “Grubb” refers to a hole that penetrates from the subcutaneous to the surface caused by the infestation of cattle fly larvae (maggots). Cattle fly larvae parasitize mainly on the back of cattle. A “pinhole” is a mark that has been stabbed by an insect during ecology, and remains that has been stabbed by a needle. “Silver float” refers to large wrinkles on the surface caused by imbalance (delamination) between two different layers of leather fibers (papillary layer (silver surface) and mesh layer (floor surface)). Most often occurs in leather duck. “Toshi wrinkle” is a wrinkle made by expansion and contraction of a movable part of a cow, and occurs mainly at the neck. “Blood muscle” means that the blood vessels of the cow remain. “Tick” refers to the part to which a tick has attracted. The silver surface is severely damaged and the appearance of the leather is significantly reduced. The “brand” is a brand mark that is attached to a part of the body of the livestock (such as a bat) in order to indicate the possession of the livestock. This burn extends deep into the dermis and significantly reduces its value as a leather. “Aigaki” is a mark of the flesh of the skin being scuffed by damaging the dermis with a knife when peeling. “Wearing off” is the mark that the blade has passed from the flesh surface to the fluff surface with a knife during the peeling, and the mark that remains when the leather is scooped with a band machine. “Garbage” is paint residue or leather back hair that was attached during the finish of leather.

The leather sheet provided as a leather material just before cutting and sewing is colored in a predetermined color after the tanning process, after the natural mark on the surface is polished and removed and embossed with a leather pattern Is done. Therefore, at the stage where the coloring process is completed, the scratches and other defects present on the leather surface are generally inconspicuous. However, as described above, when the leather is stretched, scratches and the like that were not visible become apparent.
5 (a) and 5 (b) are enlarged cross-sectional views showing an enlarged cross section of the leather sheet K attached to the inspection apparatus 1, and FIG. 5 (c) is a part of FIG. 5 (b). It is the enlarged view which expanded and represented. On the surface of the leather sheet K shown in FIG. 5A, there are scratches 60 that cannot be seen unless the leather is pulled. However, when the leather sheet K is pulled by being attached to the inspection apparatus 1, the surface portion of the scratch 60 that cannot be seen in the normal state opens as shown in FIG.

  FIG. 5C is an enlarged view of the scratch 60 described in FIG. When the first illumination 6 is turned on from the irradiation angle α, the surface of the inspection region S is illuminated with light rays. However, at this time, since the light beam of the first illumination 6 is applied to the scratch 60 from an oblique direction, the entire interior of the scratch 60 cannot be illuminated, and a shadow 61 is formed on the inner surface of the scratch 60. Then, a difference in contrast (contrast) is generated by the surface of the inspection region S that has become brighter when irradiated with light and the inner surface of the scratch 60 that is difficult to receive light and is dark. This light / dark difference can be recognized also by human vision viewed from the normal direction with respect to the surface of the inspection area S, and the defect of the inspection area S is discovered by finding the light / dark difference. ing.

When dust such as hair adheres in the painting process, a raised portion is formed on the surface. The raised portion on the surface is strongly illuminated on the light source side, and a shadow is produced on the opposite side of the light source. The defect of the inspection area S can be found by the difference in brightness between the irradiated portion and the shadowed portion.
In the above description, the case where only the first illumination 6 is used has been described. However, depending on the type, shape, and orientation of the scratch 60, it may be more appropriate to use the second illumination 7 with different irradiation directions. is there. In this case, the second illumination 7 is used instead of the first illumination 6.

  In addition, when the inspection conditions (the relationship between the inspection site and the light source position, the illuminance, the position of the inspector's eyes, etc.) are the same, the difference between the brightness and darkness that is perceived visually differs depending on the leather color to be inspected. . Therefore, depending on the color of the leather, the following measures are taken. As an example, when the leather color is black, the first illumination 6 and the second illumination 7 are used simultaneously. This is because black absorbs a lot of light and has a low light reflectivity, and it is difficult to obtain a light quantity that can discriminate a light / dark difference by using only the first illumination 6 or the second illumination 7. In the case of a bright color such as beige, only the second illumination 7 is used. This is because when the leather color is bright, it is difficult to discriminate between light and dark if the amount of light reflection is large and the illuminance is too high.

6A to 6E are photographs showing examples of defects determined using the inspection apparatus 1, and each photograph shown in the left column is a photograph of the leather surface before tension is applied, and the right column. Each photograph shown in Fig. 4 is a photograph after applying tension to each leather shown in the left column. The right column of FIG. 6A is an example of “rose scratch”, and the scratch shown in the circle was confirmed by pulling the leather. The right column of FIG. 6B is an example of “pinhole”, and a plurality of small holes are confirmed by pulling the leather as shown in the circle. Each of the right columns of FIG. 6C and FIG. 6D is an example of “open flaw”, and the flaw shown in the circle is confirmed by pulling the leather. The right column of FIG. 6 (e) is an example of “rough skin” and “pinhole”, and a small hole shown in a circle or a rough skin state is confirmed by pulling the leather. The inspection apparatus 1 according to the present embodiment can make the defects of the leather sheet appear in the state shown in the photograph of FIG. 6, and can detect the defects.

The above-described inspection apparatus and inspection method are based on the premise that the inspection apparatus and the inspection method are performed by human vision, but an image that automatically detects a difference in light and darkness that occurs in a defective portion by processing an image obtained by photographing an inspection surface. It may be performed by a processing technique. Needless to say, when an inspection is performed by image processing, a light source having a wavelength suitable for the image processing is used.
Moreover, the optimal selection of the light source according to the color of leather, etc. can be patterned as inspection conditions. Therefore, by configuring a control circuit relating to the switching of the light source, the light source selection may be performed automatically by calling the settings patterned by the leather color selection.
Even in the case of human visual inspection, the accuracy of defect detection can be improved by inspecting the inspection surface through a polarizing lens. In other words, the presence of defects can be clarified by reducing dazzling due to diffuse reflection of light, and the burden on the inspector can be reduced. If a polarizing lens is used, the amount of light decreases due to the transmission of the lens, so that adjustments such as making the illuminance of the light source higher than that during inspection with the naked eye are performed.
In the above-described embodiment, a fluorescent lamp is used as a rod-shaped light source in order to ensure a substantially uniform light amount in the longitudinal direction. However, the rod-shaped light source is not limited to fluorescent lamps, and LEDs may be linearly arranged. In addition, in order to approximate natural light or to apply to specific image processing, LEDs having RGB emission colors may be mixed or LEDs that emit light of a specific wavelength may be used.
In addition, light from a point light source such as a light bulb is shaped into a light beam having a predetermined width by passing through a slit or a lens, so that it can be used like a rod-shaped light source. The rod-shaped light source which is the configuration of the present invention includes a light source formed so as to be able to irradiate light like a rod-shaped light source by utilizing diffraction and refraction of light in this way.

  INDUSTRIAL APPLICABILITY The present invention can be used for an inspection apparatus and an inspection method for inspecting a surface of a leather.

It is an external appearance perspective view of the inspection apparatus which concerns on this Embodiment. It is an external view of the inspection apparatus which concerns on this Embodiment, (a) is a front view, (b) is a left view, (c) represents a top view. It is explanatory drawing of the test | inspection method using the test | inspection apparatus which concerns on this Embodiment. It is explanatory drawing showing the positional relationship of the leather which is a test object, and a light source. It is explanatory drawing of the defect expression which concerns on this Embodiment. It is the photograph showing an example of the fault recognized by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inspection apparatus 2 Base frame 3 1st clamp (fixing means)
4 Second clamp (fixing means)
5 Extension means 6 First illumination (illumination means)
7 Second illumination (illumination means)
DESCRIPTION OF SYMBOLS 8 Clamp bar 9 Pressure receiving member 10 Pressing surface 11 Pressure receiving surface 12, 13 Contact pad 14 Guide pole 15 Guide cylinder 16 Cylinder 20 Clamp bar 21 Press surface 22 Pressure receiving surface 23, 24 Contact pad 25 Guide pole 26 Air cylinder 27 Protection bar 28 Cover 30 Push-up member 31 Curved surface 32 Rotating fulcrum 33 Air cylinder 40 Illumination holding frame 50 Guide frame 51 Guide plate 52 Opening S Inspection area K Leather sheet

Claims (7)

A stretching means for stretching the leather sheet at a set elongation rate;
Having one or more light sources that illuminate a predetermined region of the leather sheet surface stretched by the stretching means;
A leather sheet inspection apparatus, wherein an irradiation angle of light for illuminating the predetermined area is set to an angle of 5 degrees or more and less than 90 degrees with respect to a surface of the predetermined area.   The inspection apparatus according to claim 1, wherein the light irradiation angle is set to be in a range of 5 degrees to 45 degrees. A stretching means for stretching the leather sheet at a set elongation rate;
Two rod-shaped light sources that illuminate a predetermined area of the leather sheet surface stretched by the stretching means;
The two light sources are set such that the light irradiation angle with respect to the surface of the predetermined region is in a range of 5 degrees to 45 degrees, and the light irradiation directions of both light sources are in a range of 90 degrees to 45 degrees. An inspection apparatus characterized by being arranged at different angles inside.   4. The inspection apparatus according to claim 3, wherein one of the two light sources can be selectively lit according to the color of the leather to be inspected. By illuminating a predetermined area of the stretched leather sheet surface with a light source so that the irradiation angle is 5 degrees or more and less than 90 degrees after stretching the leather sheet with the set elongation rate,
A defect such as a flaw or an adhering matter existing in the predetermined region is caused to have a bright part illuminated by the light source and a dark part difficult to be exposed to light, and the defect is discovered by using a difference in brightness produced by the light. Leather inspection method. The leather seat is stretched at the set elongation,
A first rod-shaped light source that illuminates a predetermined region of the surface of the stretched leather sheet so as to have an irradiation angle of 5 degrees or more and less than 90 degrees; and an irradiation angle similar to that of the first rod-shaped light source and the irradiation direction is By illuminating with one or both of the second rod-shaped light sources that are different within a range of 90 to 45 degrees with respect to one rod-shaped light source,
The defect such as scratches or deposits existing in the predetermined region is caused to have a bright part illuminated by the rod-shaped light source and a dark part that is not easily hit by light, and the defect is discovered using the difference in brightness produced by the light. Characteristic leather inspection method.   7. The inspection method according to claim 6, wherein the light source to be used is selected according to the color of the leather to be inspected.