Packaging film and food

Abstract

For this packaging film for packaging food, there are used at least two types of ink that reflect visible light and transmit light of a specific wavelength from infrared light or ultraviolet light; each of the inks has a different transmittance for transmitting light of the specific wavelength.

Description

Packaging films and food

[0001] The present invention relates to a packaging film for packaging food products and to food products packaged in the packaging film.

[0002] For example, rod-shaped foods such as pasta are bound with cable ties and wrapped in packaging film with information about the food printed on it, but during packaging, unnecessary cable ties can get mixed in or missing cable ties can cause the noodles to fall apart. Therefore, after packaging, workers inspect the food and cable ties by feeling them through the packaging film to check for defects in the cable ties.

[0003] Patent Document 1 also describes an inspection device that irradiates packaged food with near-infrared rays, captures a near-infrared transmission image of the irradiated packaged food using a line sensor, and inspects the presence or absence of foreign matter attached to the food inside the packaging material based on the image signal of the captured near-infrared transmission image.

[0004] JP 2009-162685 A

[0005] However, since inspection by hand as described above places a heavy burden on workers, there is a need for automation in the detection of abnormalities in packaged food, such as whether or not there are faulty cable ties, in order to reduce costs by reducing the number of workers required.

[0006] Furthermore, the inspection device described in Patent Document 1 only captures images of the cable ties and the pasta bound with the cable ties, and is unable to obtain image information that does not capture information about the pasta, etc., printed with various inks on the packaging film. As a result, it is difficult to detect whether or not the cable ties are defective after the pasta has been packaged in packaging material.

[0007] The object of the present invention is to provide a packaging film and food packaged in the packaging film that can be effectively inspected for abnormalities in food using an inspection device even when abnormalities in the food packaged in the packaging film cannot be visually confirmed.

[0008] The packaging film of the present invention is a packaging film for packaging food, and is printed with at least two types of ink that reflect visible light and transmit light of a specific wavelength from infrared light or ultraviolet light, and is characterized in that one of the inks and the other ink have different transmittances for transmitting light of the specific wavelength.

[0009] The packaging film of the present invention is also characterized in that the transmittance is 50% or more. The packaging film of the present invention is also characterized in that the specific wavelength is a wavelength in the near-infrared region. The packaging film of the present invention is also characterized in that the specific wavelength is 1200 nm or more and 1600 nm or less. The packaging film of the present invention is also characterized in that the food is noodles bound with a binding band, and the light of the specific wavelength is reflected by the binding band and the noodles.

[0010] The food of the present invention is characterized by being packaged with the packaging film of the present invention.

[0011] According to the present invention, it is possible to provide a packaging film and food packaged in the packaging film that can be effectively inspected for abnormalities in food inside the packaging film using an inspection device even when abnormalities in the food packaged in the packaging film cannot be visually confirmed.

[0012] FIG. 1 is a diagram for explaining poor binding of a cable tie used to bind noodles (pasta) according to an embodiment. FIG. 2 is a diagram showing a schematic configuration of an inspection device according to an embodiment. FIG. 3 is a block diagram showing a system configuration of an inspection device according to an embodiment. FIG. 4 is a diagram showing an example of a first image and a second image generated by a generation unit according to an embodiment. FIG. 5 is a diagram showing an example of a first composite image and a second composite image generated by a generation unit according to an embodiment. FIG. 6 is a diagram for explaining an inspection area according to an embodiment. FIG. 7 is a diagram for explaining detection of poor binding of a cable tie by a detection unit according to an embodiment. FIG. 8 is a flowchart for explaining an inspection method for inspecting for poor binding of a cable tie using an inspection device according to an embodiment.

[0013] The following describes a packaging film and food packaged with the packaging film according to an embodiment of the present invention. The packaging film according to this embodiment is a packaging material for packaging food, and is a packaging material on which at least information about the food is printed using ink that reflects visible light. Furthermore, the packaging film according to this embodiment enables inspection of food packaged in the packaging film while it is still wrapped in the packaging film (a state in which any abnormalities in the food inside the packaging film cannot be visually detected). This embodiment will describe an example in which the food is dried pasta (noodles) bound with cable ties, and the food abnormality is detected as a defective binding of the cable ties binding the dried pasta. Examples of defective binding of the cable ties include loosening of the dried pasta P due to the second-lowest cable tie B shown in FIG. 1B, the inclusion of an unnecessary cable tie B shown in FIG. 1C, and loosening of the dried pasta P due to a missing cable tie B shown in FIG. 1D, compared to a non-defective product shown in FIG. 1A.

[0014] FIG. 2 shows an example of the configuration of an inspection device for inspecting food packaged in a packaging film according to this embodiment for abnormalities. As shown in FIG. 2, the inspection device 2 includes an irradiation unit 8, a sensor 10, an imaging unit 12, and an exclusion unit 14. The inspection target 16, which is the object of inspection by the inspection device 2, is a food product packaged in the packaging film according to this embodiment, consisting of multiple bundles (six in this embodiment) of a predetermined amount of rod-shaped dried pasta P bound with cable ties B (see FIG. 1). The packaging film for packaging the dried pasta P has information about the dried pasta P printed on it using at least two types of ink that reflect visible light and transmit at least one of a first specific wavelength and a second specific wavelength of infrared light. Specifically, the surface of the packaging film is entirely or partially filled with the ink, and the information about the dried pasta P is printed in a different ink (an ink that transmits at least one of the first specific wavelength and the second specific wavelength) from the ink used for filling in the information. The ink used for filling in is one or more types, and the ink used for printing the information is also one or more types.

[0015] The first specific wavelength and the second specific wavelength are wavelengths in the near-infrared region, and in this embodiment, the first specific wavelength is 1200 nm and the second specific wavelength is 1600 nm. Each of the inks used to print the packaging film has a predetermined transmittance for light of the first specific wavelength and the second specific wavelength, and the predetermined transmittance is 50% or more. The transmittance of each ink for light of the first specific wavelength may be the same as or different from the transmittance for light of the second specific wavelength, and the transmittance of one ink for light of the first specific wavelength (second specific wavelength) may be the same as or different from the transmittance of another ink for light of the first specific wavelength (second specific wavelength).

[0016] The irradiation unit 8 includes, for example, a halogen lamp and is disposed above the conveyor 4. The irradiation unit 8 extends in the width direction of the conveyor 4 (a direction perpendicular to the plane of the paper in FIG. 1 ) and irradiates an area including the entire width of the conveyor 4 with white light. That is, the irradiation unit 8 irradiates light in a wavelength range including the visible light to infrared light range onto the inspection object 16 (dried pasta P bound with cable ties B and wrapped in packaging film) that is transported by the conveyor 4 from upstream of the inspection device 2 to below the irradiation unit 8 and the imaging unit 12. The sensor 10 is a sensor for detecting the inspection object 16 transported by the conveyor 4 and is disposed upstream of the imaging unit 12.

[0017] The imaging unit 12 includes, for example, a line sensor camera and is disposed near the irradiation unit 8 and the sensor 10 and above the conveyor 4. The imaging unit 12 captures reflected light of a first specific wavelength and reflected light of a second specific wavelength out of near-infrared light that passes through ink printed on the packaging film and is reflected by the dried pasta P and the cable ties B wrapped in the packaging film. Specifically, the imaging unit 12 receives, at the first line sensor 30 (see FIG. 3 ), the light of the first specific wavelength, i.e., light with a wavelength of 1200 nm in the near-infrared range, that has reached the first line sensor 30 via a lens (not shown) that focuses the light reflected by the target inspection object 16, a spectral prism (not shown) that splits the light into a first wavelength range including at least the first specific wavelength and a second wavelength range including the second specific wavelength, and a bandpass filter that transmits or reflects only the light of the first specific wavelength. Similarly, the imaging unit 12 receives light of the second specific wavelength, i.e., light with a wavelength of 1600 nm in the near-infrared range, that reaches the second line sensor 32 (see Figure 3) via a lens, a spectroscopic prism, and a bandpass filter that transmits or reflects only light of the second specific wavelength, at the second line sensor 32.

[0018] In this embodiment, the first specific wavelength is set to 1200 nm, which is suitable for imaging the dried pasta P, which is the object of inspection 16, and the second specific wavelength is set to 1600 nm, which is suitable for imaging the cable tie B, which is the object of inspection 16. However, the first specific wavelength and the second specific wavelength are set appropriately within the range of 1200 nm or more and 1600 nm or less based on the suitability of the object of inspection for imaging near-infrared light.

[0019] The rejection unit 14 rejects an inspection object 16 that is detected as abnormal by the inspection device 2, i.e., a defective binding of the cable tie B, as a defective product without transferring it from the conveyor 4 to the conveyor 6. The rejection unit 14 is located between the conveyors 4 and 6. An upper portion of the rejection unit 14 has a rejection opening that is substantially flush with the conveying path surfaces of the conveyors 4 and 6, and an openable / closable gate 14a is provided at the rejection opening. The gate 14a is opened and closed using, for example, a cylinder (not shown) connected to the gate 14a. If the inspection object 16 is defective, the rejection unit 14 opens the gate 14a and ejects the inspection object 16 downward to reject it (the inspection object 16 is shown by the dashed line in FIG. 2 ). On the other hand, if the inspection object 16 is non-defective, the rejection unit 14 closes the gate 14a and transfers the inspection object 16 to the conveyor 6. The conveyor 6 transports the inspection object 16 that has been determined to be non-defective after inspection by the inspection device 2 out of the inspection device 2.

[0020] Fig. 3 is a block diagram showing the system configuration of the inspection device 2 according to this embodiment. As shown in Fig. 3, the inspection device 2 includes a control unit 20 that performs overall control of each unit of the inspection device 2. The control unit 20 is connected to an irradiation unit 8, a sensor 10, an imaging unit 12, an exclusion unit 14, and a display unit 22. The control unit 20 also includes a generation unit 24 and a detection unit 26.

[0021] The generation unit 24 generates a first image based on reflected light of a first specific wavelength captured by the imaging unit 12, and a second image based on reflected light of a second specific wavelength captured by the imaging unit 12. Dried pasta P has a characteristic of absorbing more light of the second specific wavelength than light of the first specific wavelength due to the moisture content of the dried pasta P. FIG. 4A shows an example of a first image generated by the generation unit 24. As shown in FIG. 4A, the first image is captured using light of a wavelength of 1200 nm, which is suitable for capturing the dried pasta P and cable ties B, which are the inspection objects 16, as the first specific wavelength. The first image allows the dried pasta P and cable ties B to be visually recognized within the packaging film. Next, FIG. 4B shows an example of a second image generated by the generation unit 24. As shown in FIG. 4B, the second image is captured using light of a wavelength of 1600 nm, which is suitable for capturing the dried pasta P and cable ties B, which are the inspection objects 16, as the second specific wavelength. The second image allows the dried pasta P and cable ties B to be visually recognized within the packaging film. Because the dry pasta P absorbs more light of the second specific wavelength than light of the first specific wavelength, the dry pasta P in the second image is not as clear as the dry pasta P in the first image.

[0022] The generation unit 24 also generates a composite image by combining the first image and the second image to a predetermined degree. Specifically, in order to emphasize the cable tie B, the generation unit 24 generates the first composite image by algebraically calculating the luminance of the first image and the luminance of the second image from a predetermined ratio. FIG. 5A shows an example of the first composite image generated by the generation unit 24. Similarly, in order to emphasize the dried pasta P, the generation unit 24 generates a second composite image different from the first composite image by algebraically calculating the luminance of the first image and the luminance of the second image from a predetermined ratio. FIG. 5B shows an example of the second composite image generated by the generation unit 24.

[0023] The detection unit 26 detects abnormalities in the food, i.e., defective cable ties, based on the first and second composite images generated by the generation unit 24. In this embodiment, the detection unit 26 detects missing cable ties B and the presence of unnecessary cable ties B in the first composite image shown in FIG. 5A (a composite image in which the cable ties B are emphasized). The detection unit 26 determines whether or not the cable ties B of each bundle are defective based on the brightness of inspection regions R1 to R6 set within the first composite image, as shown in FIG. 6. For example, when the brightness in the longitudinal direction of the inspection region R1 is as shown in FIG. 7A (horizontal axis: longitudinal position of the inspection region R1, vertical axis: brightness), the detection unit 26 determines that the position, height, and width of the brightness peak representing the cable tie B are within a predetermined range and that the number of brightness peaks is one. Therefore, the detection unit 26 determines that the cable ties B binding the dried pasta P in the inspection region R1 are not missing and that unnecessary cable ties B are not present within the inspection region R1. On the other hand, if there is no brightness peak in the longitudinal direction of the inspection area R1, if the position, height, and width of the brightness peak are not within predetermined ranges, and if it is determined from the second composite image described below that the cable tie B is loose, the detection unit 26 determines that the cable tie B binding the dried pasta P in the inspection area R1 is missing. Furthermore, if the position of the brightness peak in the longitudinal direction of the inspection area R1 is outside the predetermined range, the detection unit 26 determines that an unnecessary cable tie B has been mixed in the inspection area R1.

[0024] In addition, missing cable ties B that bind the dried pasta P in the inspection areas R2 to R5 and the presence of unnecessary cable ties B in the inspection areas R2 to R5 can also be detected from the brightness of the inspection areas R2 to R5, in the same way as the inspection area R1.

[0025] Furthermore, the detection unit 26 detects looseness of the cable ties B from the second composite image shown in FIG. 5B (a composite image in which the dried pasta P is emphasized). The detection unit 26 determines whether or not the cable ties B of each cable tie are defective based on the brightness of the cross section of the cable tie in the width direction. For example, when the brightness of the cross section of the cable tie in the width direction (average brightness from the cross section at the first predetermined position to the cross section at the second predetermined position in the longitudinal direction of the cable tie) is in the state shown in FIG. 7B (horizontal axis: position in the width direction of the cable tie, vertical axis: brightness), the detection unit 26 determines that there is no looseness in the six cable ties B binding the dried pasta P because the positions, heights, and widths of the brightness peaks indicating the gaps between adjacent cable ties are within predetermined ranges and there are five brightness peaks. The first predetermined position is a position a predetermined distance from one end of the binding body in the longitudinal direction (for example, 10 mm from the one end), and the second predetermined position is a position a predetermined distance from the other end of the binding body in the longitudinal direction (for example, 10 mm from the other end).

[0026] On the other hand, if the number of brightness peaks in the width direction of the bundle is four or less, the detection unit 26 determines that there are no gaps between adjacent bundles, i.e., the dried pasta P is spread out and not bound, and therefore determines that there is a missing or loose cable tie B. Furthermore, if the height and width of the brightness peaks in the width direction of the bundle are not within a predetermined range, the detection unit 26 determines that there are small gaps between adjacent bundles, i.e., the dried pasta P is loosely bound and the cable tie P is loose.

[0027] The display unit 22 includes a liquid crystal panel or the like, and displays the first image, the second image, the first composite image, and the second composite image generated by the generation unit 24, as well as the detection results detected by the detection unit 26, and the like.

[0028] Next, an inspection method for inspecting the inspection object 16 (dried pasta P packaged in the packaging film according to this embodiment) for abnormalities using the inspection device 2 according to this embodiment will be described. Figure 8 is a flowchart for explaining the processing executed to inspect the inspection object 16 for binding defects.

[0029] First, the control unit 20 outputs a control signal to the irradiation unit 8, causing the irradiation unit 8 to start irradiation, thereby irradiating the inspection object 16, which is being transported by the conveyor 4 from upstream of the inspection device 2 to below the irradiation unit 8 and the imaging unit 12, with light in a wavelength range including the infrared range (step S10).

[0030] Next, the control unit 20 acquires a signal output from the sensor 10 and determines, based on the signal from the sensor 10, whether the inspection object 16 has reached below the imaging unit 12 (step S11). If it is determined in step S11 that the inspection object 16 has reached below the imaging unit 12 (step S11: Yes), the control unit 20 outputs a control signal to the imaging unit 12 to start imaging by the imaging unit 12 (step S12). Specifically, the control unit 20 causes the imaging unit 12 to capture reflected light of a first specific wavelength and reflected light of a second specific wavelength out of near-infrared light that has passed through the ink used to print the packaging film and is reflected by the dried pasta P and the cable tie B.

[0031] On the other hand, if it is determined in step S11 that the object to be inspected 16 has not reached below the imaging unit 12 (step S11: No), the control unit 20 repeats the processing of step S11 until it is determined in step S11 that the object to be inspected 16 has reached below the imaging unit 12.

[0032] Next, the control unit 20 acquires the signal output from the sensor 10 and determines whether or not the inspection object 16 has passed below the imaging unit 12 based on the signal from the sensor 10 (step S13). If it is determined in step S13 that the inspection object 16 has passed below the imaging unit 12 (step S13: No), the control unit 20 outputs a control signal to the imaging unit 12 and stops imaging by the imaging unit 12 (step S14).

[0033] On the other hand, if it is determined in step S13 that the object to be inspected 16 has not passed below the imaging unit 12 (step S13: Yes), the control unit 20 repeats the processing of step S13 until it is determined in step S13 that the object to be inspected 16 has passed below the imaging unit 12.

[0034] Next, the generation unit 24 of the control unit 20 generates a first image based on the reflected light of the first specific wavelength captured by the imaging unit 12, and generates a second image based on the reflected light of the second specific wavelength captured by the imaging unit 12. Furthermore, the generation unit 24 generates a composite image by combining the first image and the second image to a predetermined degree (step S15).

[0035] Specifically, the generation unit 24 algebraically calculates the luminance of the first image and the luminance of the second image from a predetermined ratio to generate a first composite image (the image shown in FIG. 5A) in which the cable tie B is emphasized. Similarly, the generation unit 24 algebraically calculates the luminance of the first image and the luminance of the second image from a predetermined ratio to generate a second composite image (the image shown in FIG. 5B) in which the dried pasta P is emphasized.

[0036] Next, the detection unit 26 of the control unit 20 detects whether or not there are any defective bindings of the dried pasta P based on the first and second composite images generated in step S15 (step S16). Specifically, the detection unit 26 detects missing or unwanted binding ties B from the brightness of the first composite image in which the binding ties B are emphasized. The detection unit 26 determines whether or not the binding ties B binding the dried pasta P in the inspection regions R1 to R6 are missing or whether or not unwanted binding ties B are mixed in the inspection regions R1 to R6, for example, based on whether or not the position, height, and width of the brightness peaks representing the binding ties B in the longitudinal direction of the inspection regions R1 to R6 (see FIG. 6 ) are within predetermined ranges, and the number of brightness peaks.

[0037] The detection unit 26 also detects looseness of the cable tie B from the brightness of the second composite image in which the dried pasta P is emphasized. The detection unit 26 determines whether the cable tie B binding the dried pasta P is loose based on, for example, whether the position, height, and width of the peaks (peaks of brightness indicating gaps between adjacent bundles) of the brightness of the cross section in the width direction of the bundle (average brightness from the cross section at the first predetermined position to the cross section at the second predetermined position in the longitudinal direction of the bundle) are within a predetermined range, and the number of brightness peaks.

[0038] Next, the control unit 20 displays the first image, the second image, and the composite image generated in step S15, as well as the detection results detected in step S16, on the display unit 22 (step S17).

[0039] Next, if the control unit 20 determines from the detection results in step S16 that the dried pasta P is poorly bound, i.e., if there is no brightness peak indicating a cable tie B in the longitudinal direction of any of the inspection areas R1 to R6, if the position, height, and width of the brightness peak in the longitudinal direction of any of the inspection areas R1 to R6 are not within a predetermined range, if the number of brightness peaks indicating gaps between adjacent bundles in the width direction of the bundle is four or less, or if the height and width of the brightness peak in the width direction of the bundle are not within a predetermined range (step S18: Yes), the control unit 20 proceeds to step S19. Specifically, the control unit 20 outputs a control signal to the rejection unit 14 to open the gate 14a provided at the rejection port of the rejection unit 14 and eject the inspection object 16 downward through the rejection port. That is, the control unit 20 rejects the inspection object 16 determined to be defective in step S18 without transferring it to the conveyor 6. Furthermore, after rejecting the defective inspection objects 16, the control unit 20 closes the rejection gate 14a.

[0040] On the other hand, if the control unit 20 determines from the detection results in step S16 that there is no poor binding of the dried pasta P, i.e., if there is a brightness peak indicating the cable tie B in the longitudinal direction of the inspection areas R1 to R6, if the position, height, and width of the brightness peak in the longitudinal direction of the inspection areas R1 to R6 are within a predetermined range, if the number of brightness peaks indicating the gap between adjacent bundles in the width direction of the bundle is five, and if the height and width of the brightness peak in the width direction of the bundle are within a predetermined range (step S18: No), it will hand over the inspection object 16 to the conveyor 6 as a good product.

[0041] With the packaging film and dried pasta P (food product) packaged in this packaging film according to this embodiment, the dried pasta P packaged in an opaque packaging film can be effectively inspected for binding defects in the dried pasta P while it is still packaged in the packaging film using the inspection device 2. That is, even if the dried pasta P is packaged in a packaging film that is filled in with ink and has information about the dried pasta P printed on it, because the packaging film is printed with at least two types of ink that reflect visible light and transmit light of the first specific wavelength and the second specific wavelength, an image can be obtained that highlights the dried pasta P and cable ties B inside the packaging film, and missing or loose cable ties B, as well as the inclusion of unnecessary cable ties B, can be quickly and effectively detected.

[0042] In this embodiment, a packaging film printed with at least two types of ink that reflects visible light and transmits light of a first specific wavelength and a second specific wavelength has been described as an example, but the present invention can also be applied to a packaging film printed with at least two types of ink that reflects visible light and transmits light of three or more specific wavelengths. In this case, the imaging unit 12 includes a line sensor that can receive light of three or more specific wavelengths, and the generation unit 24 generates a composite image by combining three or more images to a predetermined degree.

[0043] Furthermore, in this embodiment, an example is given in which one cable tie B is used to tie the center of the dried pasta P, but it is also possible to inspect for defective binding when two cable ties B are used to tie both ends of the dried pasta P.

[0044] In addition, in this embodiment, the first specific wavelength and the second specific wavelength are wavelengths in the near-infrared range, but the first specific wavelength and the second specific wavelength may be wavelengths in the infrared range other than the near-infrared range. Furthermore, the first specific wavelength and the second specific wavelength may be wavelengths in the ultraviolet range. In this case, the inspection object is a food packaged in a packaging film printed with at least two types of ink that reflects visible light and transmits ultraviolet light of specific wavelengths (at least two specific wavelengths).

[0045] Furthermore, in this embodiment, dried pasta P bound with cable ties B has been described as an example of the inspection object 16, but other dried noodles such as somen noodles bound with cable ties may also be used. Furthermore, in this embodiment, inspection is performed for improper binding of cable ties B, but inspection may also be performed for abnormalities in other foods, such as the presence of foreign matter in the packaging film. In this case, the inspection object may not only be dried noodles bound with cable ties, but also dried noodles not bound with cable ties or foods other than dried noodles.

[0046] 2...inspection device, 4, 6...conveyor, 8...irradiation unit, 10...sensor, 12...imaging unit, 14...exclusion unit, 14a...gate, 16...object to be inspected, 20...control unit, 22...display unit, 24...generation unit, 26...detection unit, B...cable tie, P...dried pasta, R1 to R6...inspection area.

Claims

1. A packaging film for packaging food, which is printed with at least two types of ink that reflects visible light and transmits light of a specific wavelength from infrared light or ultraviolet light, and which is characterized in that one of the inks and the other ink have different transmittances for transmitting light of the specific wavelength.

2. The packaging film according to claim 1, wherein the transmittance is 50% or more.

3. The packaging film according to claim 1 or 2, wherein the specific wavelength is a wavelength in the near-infrared region.

4. The packaging film according to claim 3, wherein the specific wavelength is between 1200 nm and 1600 nm.

5. A packaging film according to claim 1 or 2, characterized in that the food is noodles bound with a cable tie, and the light of the specific wavelength is reflected by the cable tie and the noodles.

6. A food product packaged in the packaging film according to claim 1 or 2.

Images