JP2000292369A - Quality inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect precisely existence of a defect on a test surface without being influenced by falling dust or the like in the middle of conveyance of a test object. SOLUTION: In the middle of conveyance, by a conveyance means 1, of a test object, for example, a corrugated cardboard 51, in the state where a printed test surface thereof is faced downward, the test surface is illuminated by illumination light sources 2, 3, and imaged by an imaging camera 7 of an imaging device 6 through a light transmitting plate 13. The imaging camera 7 is housed in an optical box 8 having the light transmitting plate 13 on the front thereof. The light transmitting plate 13 is placed at an angle relative to a horizontal plane, to make adhesion of falling dust or the like difficult. Hereby, even if the dust or the like adheres by any chance, it can be removed simply and surely by spraying air or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting an object to be inspected, such as a corrugated cardboard for a packaging box, which is conveyed in such a manner that the surface to be inspected such as a printed surface on the front side faces downward. Printing errors on the surface, detect the presence or absence of various defects such as dirt, or transparent, etc., light-transmitting long, or fixed-size film, transparent, such as a printed pattern, light-transmitting long, or The present invention relates to a quality inspection device used to detect the presence or absence of various defects such as molding defects, dirt, and printing errors in a fixed-size film.

[0002]

2. Description of the Related Art Conventionally, for example, cardboard has been used as a packaging box for accommodating a plurality of beer bottles. The manufacturing process of such a packaging box will be briefly described. First, as shown in FIG. 4 (a), a corrugated cardboard 51 cut into a rectangular shape of a desired size is sequentially supplied to a letterpress printing machine to form the corrugated cardboard 51. Display contents 52 such as desired figures and characters are printed at the packaging box development position on the front surface. Next, the printed cardboard 51 is supplied to the press section, and the press section supplies the corrugated cardboard 51 shown in FIG.
As shown in (b), the corrugated cardboard 51 is formed with slits 53 and the like so as to have an unfolded shape of the packaging box, and the perforated intermittent cutout (for cutout) is formed along the predetermined cutout outline. The part 54 is formed. Next, the pressed cardboard 51 is supplied to the stripping section, and as shown in FIG. 4C, the packaging box structure 55 is punched along the intermittent section 54 to form a peripheral portion 56 (see FIG. 4B). Remove the debris.
The packaging box members 55 thus formed are sequentially discharged and stacked so that the printing surface on the front side faces downward.

[0003] The packaging box structure 55 as described above is used in a state of being stacked such that the printing surface on the front side faces downward.
That is, a desired number of beer bottles can be placed on the upper surface serving as the inner surface of the stacked uppermost packaging box structure 55, and the packaging box structure 55 can be assembled so as to surround the beer bottle by folding. Then, the beer bottle can be shipped in a state of being packed in a packaging box.

It is necessary to detect various defects such as printing errors and dirt on the surface side of the packaging box as described above. Conventionally,
An inspection apparatus using an imaging camera is known to detect the presence or absence of such a defect. In order to detect the presence or absence of a defect on a printed surface with such an inspection device, as shown in FIG. 4A, after the display content 52 is printed on the cardboard 51, or as shown in FIG. After forming the slit 53 and the like and the intermittent part 54 by press working on the cardboard 51,
Alternatively, as shown in FIG. 4C, an image is taken by an imaging camera while being conveyed in any planar state after being punched out as the packaging box constituting body 55.

In a molding process, for example, a transparent or other light-transmitting long film used for manufacturing a laminate or a packaging bag may be mixed with foreign resin pellets or the like as a foreign matter. Need to detect. When printing, it is necessary to detect defects after printing. Conventionally, to detect such a defect, the film is conveyed and illuminated by an illumination light source from below while the film is being conveyed, and the upper surface of the transmitted and illuminated film is imaged by an imaging camera from above.

[0006]

However, in order to inspect defects after printing the display contents on the cardboard 51 with a printing machine, it is necessary to remodel the printing machine in order to install an inspection device, which is expensive. . On the other hand, in the transport process from the press section of the cardboard 51 to the discharge section of the packaging box structure 55, by using the space below, to inspect the downward printing surface using the inspection device, it is temporarily, It becomes possible.

However, when the imaging camera is turned upward and an image of a downward printing surface is taken, various dusts and the like, such as debris generated when the cardboard 51 is punched, fall on the lens portion of the imaging camera, and the dust or the like causes a defect on the printing surface. May be erroneously determined. In order to prevent this, it is conceivable to blow air to the lens part to remove dust and the like, but this air blowing work must be performed frequently, and a frame is provided around the lens part. Therefore, discharge of dust and the like is prevented by this frame, dust and the like cannot be removed cleanly, and there is a risk of erroneous determination. For this reason, the quality of the inspection object transported with the inspection surface facing downward as described above is not actually performed.

In the inspection of a film, a light source arranged below the film is housed in a box, and light from the light source is passed through a light transmitting plate provided on a front surface (upper surface) of the box to illuminate the film. However, if various kinds of dust or the like fall on the light transmitting plate, the imaging camera may take an image of the dust or the like on the light transmitting plate through the film and erroneously determine the presence or absence of a defect. In order to prevent this, it is conceivable to blow air onto the light transmitting plate to remove dust and the like, as described above. However, this air blowing work must be performed frequently, and Since there is a mounting frame around the transmission plate, the mounting frame prevents the discharge of dust and the like, so that the dust and the like cannot be removed neatly, and there is a risk of erroneous determination.

An object of the present invention is to solve the above-described conventional problems, and to transport an object to be inspected during transportation.
The inspection target surface can be imaged so as not to be affected by falling dust and the like, and erroneous determination can be prevented. Therefore, the detection accuracy of the presence or absence of a defect on the inspection target surface can be improved. It is an object of the present invention to provide a quality inspection device.

[0010]

In order to solve the above-mentioned problems, a quality inspection apparatus according to the present invention includes an illuminating means for illuminating the inspection object while the inspection object is being conveyed, and illumination by the illumination means. An imaging unit configured to image a downwardly-facing inspected surface of the inspected object; an imaging unit having a covering body that covers the imaging unit in an image-capable state of the inspected surface; Determining means for determining the presence or absence of a defect on the surface to be inspected.

[0011] In the above configuration, the imaging unit may be used for imaging, or the imaging unit may be used in combination with an imaging camera and a mirror for reflecting the surface to be inspected by the imaging camera. In addition, a light transmitting cover can be used as the cover, and the light transmitting cover is preferably set to have an angle with respect to a horizontal plane. In addition, an optical system box that houses an imaging unit can be used as a cover, and the surface to be inspected can be imaged by the imaging unit through a light transmission plate of the optical system box. It is preferable to set the angle. Further, the illumination means can be housed in the optical system box.

In order to solve the above-mentioned problems, another quality inspection apparatus according to the present invention includes an illumination light source for transmitting and illuminating the inspection object from below while the optically transparent inspection object is being conveyed. Illuminating means having a cover for covering the surface to be inspected so as to be capable of transmitting illumination, imaging means for imaging an upwardly-facing inspected surface of the inspection object which is illuminated by the illuminating means, and output from the imaging means Determining means for determining the presence or absence of a defect on the surface to be inspected based on the above.

[0013] In the above structure, the coating may have a spherical shape or a cylindrical shape protruding upward above the illumination light source.
Alternatively, it is preferable to select any one of an inclined shape having an angle with respect to a horizontal plane.

According to the quality inspection apparatus of the present invention configured as described above, the downwardly inspected surface of the object to be inspected is imaged by the imaging unit through the covering while the object to be inspected is being conveyed. The covering can easily remove the falling dust and the like, and can image the surface to be inspected so as not to be affected by the dust and the like. Can be.

According to another quality inspection apparatus of the present invention constructed as described above, while the object is being conveyed, the object to be inspected is transmitted and illuminated through the covering from below by the illumination light source, and the object is inspected. By taking an image of the upward inspection surface of the object from above by the imaging means, the covering body can easily remove falling dust and the like, and image the inspection surface so as not to be affected by the dust and the like. Therefore, it is possible to prevent an erroneous determination as to the presence or absence of a defect on the surface to be inspected.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described. 1 and 2 show a quality inspection apparatus according to a first embodiment of the present invention. FIG. 1 is a partially cutaway side view, and FIG. 2 is a rear view.

In this embodiment, the object to be inspected is
As shown in FIG. 4 (b), a corrugated cardboard 51 is used in which a slit 53 or the like and an intermittent portion 54 are formed in a press section, and the corrugated cardboard 51 is pressed so that the printed surface of the display content 52 faces downward. An example in which the present invention is applied to a transport unit that supplies a sheet to a stripping unit will be described.

In FIG. 1 and FIG. 2, reference numeral 1 denotes a conveying means, which is an unnecessary portion 56 (see FIG.
(See (b)), the printed surface of the display contents 52 and the like can be conveyed with the printed surface facing downward. As an example, a belt conveyor is used. Reference numerals 2 and 3 denote illumination light sources that reflect and illuminate the surface to be inspected, which is a downwardly facing component of the cardboard box 51 that is conveyed, and are, for example, fluorescent lamps. It is set so that reflected illumination can be performed almost uniformly over the entire width. Lighting sources 2 and 3 are box 4
The surface to be inspected can be reflected and illuminated through a transparent or milky white light transmitting plate (not shown) which is exchangeably supported in the box 5 and is provided at the front of the boxes 4 and 5 at an angle.

Reference numeral 6 denotes an image pickup means for picking up an image of the downward surface to be inspected of the cardboard 51 from the lower vertical direction. The imaging means 6 in the illustrated example includes a cardboard 51 conveyed as an imaging unit.
One camera 7 (or a plurality of cameras in the width direction of the cardboard 51) such as a CCD line sensor having a telephoto lens 7a is used so that the inspection surface can be sequentially imaged over the entire width. The imaging camera 7 is housed in an openable and closable optical system box 8 which is a cover, and a back plate 9 of the optical system box 8 is screwed into a machine frame 11 through an elongated hole 10.
2 allows the position to be adjusted in the direction of approaching and separating from the cardboard 51. The main body of the optical system box 8 is formed of a metal such as iron or aluminum, and a transparent light transmitting plate 13 made of glass or the like is attached so as to have an angle with respect to a horizontal plane so as to close a front opening. The imaging camera 7 can image the surface to be inspected of the cardboard 51 from between the illumination light sources 2 and 3 through the light transmitting plate 13. In the illustrated example, the light transmitting plate 13 is set to be inclined at about 45 degrees with respect to the horizontal plane.

Reference numeral 14 denotes a determination unit, for example, which compares the density level of the multi-tone image data obtained from the output of the imaging camera 7 with the reference density level to determine whether or not there is a defect on the inspection surface.

The operation of the above configuration will be described below. As described above, the corrugated cardboard 51 on which the slit 53 and the like and the intermittent portion 54 are formed in the press section after the display content 52 is printed is transported so that the printing surface faces downward.
Is transported to the stripping section in the next step. In the course of this conveyance, the downward inspection surface of the cardboard 51 extends from the front end to the rear end, and is sequentially reflected and illuminated by the illumination light sources 2 and 3. The image is sequentially taken by the image taking camera 7 from between 2 and 3.

While the cardboard 51 is being conveyed, the judging means 14 uses the cardboard 5
The presence / absence of a defect on the inspection target surface is determined.
As an example, 25 sequentially output from the imaging camera 7
A multi-tone area image is created from the data of the six-step multi-tone line image, and the density level of each part of the multi-tone area image is set to the density of the corresponding part of the 256-tone multi-tone area image of the reference image. Compared with the level, the presence or absence of a defect is determined based on the allowable value of the density level difference between the corresponding portions of the two images.

In order to sort the non-defective cardboard 51 and the defective cardboard 52, as an example, the judgment result of the judgment means 14 is statistically processed by a personal computer (not shown) and the history is stored. ,
Inspection data in which quality of all the corrugated boards 51 included in the stacked bundle of the corrugated boards 51 for each lot is good or bad is output. Thereby, based on the inspection data, the packaging box structure 55
Defective products can be discharged from the inside (see FIG. 4C). As another example, the cardboard 51 determined to be defective by the determining unit 14 is discharged to the outside of the transporting unit 1 by a discharging unit (not shown) while being transported to the stripping unit in the next step.

As described above, the downward inspection surface of the cardboard 51 is imaged by the imaging camera 7 through the light transmitting plate 13, and the light transmitting plate 13 is inclined so as to have an angle with respect to the horizontal plane. Therefore, dust or the like dropped from the cardboard 51 or the like can be prevented from falling along the inclined surface of the light transmitting plate 13 and accumulating on the light transmitting plate 13. Even if it stops, it can be easily and reliably removed by blowing air or the like. Therefore, when the imaging surface of the inspection target is imaged by the imaging camera 7, it is possible to improve the detection accuracy by preventing the imaging of the dust or the like. In addition, since the imaging camera 7 is housed in the optical system box 8, the detection accuracy can be further improved by further reducing the influence of dust and the like.

Next, a second embodiment of the present invention will be described. FIG. 3 is a partially cutaway side view showing a quality inspection device according to a second embodiment of the present invention.

In the present embodiment, as shown in FIG. 3, the downwardly inspected surface of the cardboard 51 conveyed by the conveying means 1 is sequentially reflected and illuminated over the entire width by the illumination light source 21, and is opposite to the illumination light source 21. The inspection surface is sequentially imaged over the entire width by the imaging means 22 from the side. The imaging unit 22 in the illustrated example includes, as an imaging unit, a reflection mirror 23,
The imaging camera 7 and the reflection mirrors 23 and 24 are housed in an optical system box 25 which is a cover. An opening is formed in the upper part of the optical system box 25 on the side of the illumination light source 21, and a transparent light transmitting plate 26 made of glass or the like is formed so as to close this opening so as to have an angle with respect to a horizontal plane. In the example shown, it is mounted so as to stand substantially perpendicular to the horizontal plane. Then, the imaging camera 7 passes through the light transmitting plate 26,
The inspection surface of the cardboard 51 facing downward is reflected by the reflection mirrors 23 and 2.
4 can be imaged. Other configurations and quality inspection operations are the same as in the first embodiment.

By arranging the light transmitting plate 26 in the vertical direction as in the present embodiment, it is possible to more effectively prevent the adhesion of falling dust and the like, and to further improve the detection accuracy of the surface to be inspected. Can be done.

In each of the above inspection methods, although not shown, an illumination light source may be accommodated in an optical system box accommodating an imaging unit. Although not shown, it is also possible to use only a light transmitting plate, expand it to the side, and use it as a light transmitting cover to eliminate the need for an optical system box. In short, the imaging unit can be covered only with the light transmitting cover so as not to be affected by dust or the like. Further, the light transmitting plate and the light transmitting cover may be provided with a filter on a transparent material. Further, the light transmitting plate 26 in the second embodiment may be formed so as to have an overhanging angle with respect to the horizontal plane, and various shapes to which dust and the like hardly adhere can be selected. . Further, when the space below the transported inspection object is narrow, the imaging camera may be oriented in the horizontal direction, and the inspection surface may be imaged through the light transmitting plate by using a reflection mirror.
In this case, the illumination light source, the imaging unit, and the like can be pulled out to the side and replaced. The illumination light source is a combination of a bright field light source and a dark field light source to make it easier to see the color components of the color ink. The light is scattered almost uniformly over the whole, and the detection accuracy of the uneven portion can be improved. Further, the illumination light source is not limited to a fluorescent lamp, and various lamps such as a halogen lamp can be used. In addition, various design changes can be made without departing from the basic technical concept.

Next, a third embodiment of the present invention will be described. FIG. 5 is a partially cutaway side view showing a quality inspection apparatus according to a third embodiment of the present invention.

In this embodiment, a case where the invention is applied to a long or fixed-size light-transmitting film as an object to be inspected will be described. In FIG. 5, reference numeral 31 denotes a film which is conveyed (runs) by a conveying means (not shown).
Reference numeral 32 denotes an illumination light source disposed below a portion of the film 31 which is conveyed in the horizontal direction, and is constituted by, for example, a fluorescent lamp, and can illuminate the conveyed film 31 substantially uniformly in a continuous manner over the entire width. It is set as follows. The illumination light source 32 is exchangeably supported in an openable and closable box 33 which is a cover, and has a milky white light transmitting plate 34 provided above (in front of) the box 33 and a curved surface (kamaboko shape) upward thereabove. A transparent light transmitting member 35 protruding from the light transmitting member 35 is provided.
Is set to milky white, the light transmitting plate 34 is not required. ).

Numeral 36 denotes an image pickup means for picking up an image of the surface to be inspected facing upward of the film 31 from above in the vertical direction, and is arranged to face the illumination light source 32 with the film 31 interposed therebetween. The imaging means 36 in the illustrated example is provided with a telephoto lens 37a so that the inspection surface of the film 31 conveyed as an imaging unit can be sequentially imaged over the entire width.
One camera 37 (or a plurality of cameras in the width direction of the film 31) such as a CD line sensor is used. The imaging camera 37 is housed in an openable / closable optical system box 38,
The surface to be inspected of the film 31 can be imaged through a transparent light transmitting plate (a transparent material may be provided with a filter) 39 on the front side of the optical system box 38.

Numeral 40 denotes a judging means, for example, which compares the density level of the multi-tone image data obtained from the output of the imaging camera 37 with a reference density level to judge the presence or absence of a defect on the inspection surface.

The operation of the above configuration will be described below. The film 31 is transported by the transport unit such that the surface to be inspected faces upward. During this transport, the film 31 is turned by the illumination light source 32 on the lower side thereof into the light transmitting plate 3.
The light is transmitted and illuminated through the light transmitting member 4 and the light transmitting member 35, and the illuminated portion is sequentially imaged by the imaging camera 37.

During the transport of the film 31, the imaging camera 37
The presence / absence of a defect on the surface to be inspected of the film 31 is determined by the determination means 40 in the same manner as described above based on the imaging data obtained by Based on the result of this determination, it is possible to sort out non-defective products and defective products.

By covering the upper portion of the illumination light source 32 with the curved light transmitting member 35 as described above, the fallen dust and the like fall along the curved surface of the light transmitting member 35, and should be avoided. Even if dust or the like stops on the top, it can be easily and reliably removed by blowing air or the like.
Therefore, when imaging the surface to be inspected by the imaging camera 37, detection accuracy can be improved without being affected by dust or the like. Also, the illumination light source 32 is
By keeping the height within the range, it is possible to further improve the detection accuracy by preventing the influence of dust and the like.

Next, a fourth embodiment of the present invention will be described. FIG. 6 is a partially cutaway side view showing a quality inspection device according to a fourth embodiment of the present invention.

The feature of this embodiment is that the light transmitting member 4 above the illumination light source 32 is distinctive from FIG.
1 is formed in a cylindrical shape using a milky white material, so that falling dust and the like are hardly attached thereto, and can be easily and reliably removed. This is the same as the fourth embodiment.

Next, a fifth embodiment of the present invention will be described. FIG. 7 shows a quality inspection apparatus according to a fifth embodiment of the present invention, and is a partially broken side view.

The feature of this embodiment is that, as is clear from FIG.
2 is inclined using a milky white material so as to have an angle with respect to the horizontal plane, so that falling dust and the like are hardly attached and can be easily and reliably removed. The configuration and operation are the same as in the fourth embodiment.

In the third to fifth embodiments, only the light transmitting plate is used, and the light transmitting plate is expanded so as to extend to the side to cover the illumination light source in a cover shape.
The box can be dispensed with. The illumination light source is a combination of bright field and dark field for easy acquisition of the color components of the color ink, or a light diffusing member is provided in front to allow light from the illumination light source to cover the entire imaging area of the inspection surface. On the other hand, the light can be scattered almost uniformly to improve the detection accuracy of the uneven portion. Further, the illumination light source is not limited to a fluorescent lamp, and various lamps such as a halogen lamp can be used. In addition, various design changes can be made without departing from the basic technical concept.

[0041]

As described above, according to the quality inspection apparatus of the present invention, the downwardly inspected surface of the object to be inspected is imaged by the imaging section through the covering member while the object to be inspected is being conveyed. The covering can easily remove the falling dust and the like, and can image the surface to be inspected so as not to be affected by the dust and the like. Can be. Therefore, it is possible to improve the accuracy of detecting the presence or absence of a defect on the downward inspection surface.

Further, a light transmitting cover is used as the coating,
By making the cover have an angle with respect to the horizontal plane, it is possible to make it difficult for dust and the like to adhere. Even if dust and the like adhere to the cover, it can be easily and reliably removed by blowing air or the like. And the detection accuracy can be further improved.

Further, by placing the image pickup unit in the optical system box, it is possible to further prevent the influence of dust and the like, and to further improve the detection accuracy. Further, by making the light transmitting plate of the optical system box have an angle with respect to the horizontal plane, it is possible to effectively prevent the adhesion of dust and the like as described above.

According to another quality inspection apparatus of the present invention, while the inspection object is being conveyed, the inspection object is transmitted and illuminated from below through the covering by the illumination light source, and the inspection object is directed upward. Is imaged from above by the imaging means, the covering body can easily remove dust and the like falling down, and the surface to be inspected can be imaged without being affected by dust and the like. Erroneous determination as to the presence or absence of a defect can be prevented. Therefore, it is possible to improve the detection accuracy of the presence or absence of a defect in the light-transmissive inspection object.

Further, by projecting the light transmitting member upward in a curved surface, or forming the light transmitting member in a cylindrical shape, or by making an angle with respect to a horizontal plane, dust and the like hardly adhere.
Should it adhere, it can be easily and reliably removed by blowing air or the like.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing a quality inspection apparatus according to a first embodiment of the present invention.

FIG. 2 is a rear view showing the quality inspection apparatus.

FIG. 3 is a partially cutaway side view showing a quality inspection apparatus according to a second embodiment of the present invention.

FIGS. 4 (a) to 4 (c) are explanatory diagrams of a manufacturing order of a packaging box structure made of cardboard.

FIG. 5 is a partially broken side view showing a quality inspection device according to a third embodiment of the present invention.

FIG. 6 is a partially cutaway side view showing a quality inspection device according to a fourth embodiment of the present invention.

FIG. 7 is a partially broken side view showing a quality inspection apparatus according to a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conveying means 2 Illumination light source 3 Illumination light source 6 Imaging means 7 Imaging camera 8 Optical system box 13 Light transmission plate 14 Judgment means 21 Illumination light source 22 Imaging means 23 Reflection mirror 24 Reflection mirror 25 Optical system box 26 Light transmission plate 31 Film 32 Lighting Light source 33 Box 35 Light transmitting member 36 Imaging means 37 Imaging camera 38 Optical system box 40 Judging means 41 Light transmitting member 42 Light transmitting member 51 Cardboard (inspected object)

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshitaka Hikami 1-5 Kagamiba Oyanagi-cho, Minami-ku, Kyoto D-Engineering Co., Ltd. F-term (reference) 2G051 AA32 AA90 AB01 AB02 AB11 AB20 BB20 CA03 CA04 CA06 CB01 CC20 DA06 DA17 EA11 EB01

Claims (10)

[Claims] An illumination unit configured to illuminate the inspection object while the inspection object is being transported; an imaging unit configured to image a downward inspection surface of the inspection object illuminated by the illumination unit; A quality inspection apparatus comprising: imaging means having a cover for covering the inspection surface in an image-capable state; and determination means for determining the presence or absence of a defect on the inspection surface based on an output from the imaging unit. . 2. The quality inspection device according to claim 1, wherein the imaging unit comprises an imaging camera. 3. The quality inspection apparatus according to claim 1, wherein the imaging unit includes an imaging camera, and a mirror that reflects the surface to be inspected on the imaging camera. 4. The quality inspection apparatus according to claim 1, wherein the cover is a light transmitting cover. 5. The quality inspection apparatus according to claim 4, wherein the light transmitting cover is set to have an angle with respect to a horizontal plane. 6. The optical device according to claim 1, wherein the cover is an optical system box for accommodating an image pickup unit, and the surface to be inspected is imaged by the image pickup unit through a light transmitting plate of the optical system box. Quality inspection device described in Crab. 7. The quality inspection apparatus according to claim 6, wherein the light transmission plate is set to have an angle with respect to a horizontal plane. 8. The quality inspection apparatus according to claim 6, wherein the illumination means is housed in an optical system box. 9. An illumination light source for transmitting and illuminating the object to be inspected from below while transporting the light-transmissive object to be inspected, and a cover for covering the illumination light source in a state where the surface to be inspected can be transmitted and illuminated. Illuminating means, imaging means for imaging an upwardly-facing inspected surface of the inspection object transmitted and illuminated by the illuminating means, and judging the presence or absence of a defect on the inspected surface based on an output from the imaging means A quality inspection device comprising a determination unit. 10. The quality inspection apparatus according to claim 9, wherein the coating is selected from a curved surface projecting upward above the illumination light source, a cylindrical shape, or an inclined shape having an angle with respect to a horizontal plane.