Color inspection device, and injection molding system

Abstract

To provide a color inspection device that inspects, with a simple configuration, the color density and color unevenness of a molded article molded by injection molding, and an injection molding system.SOLUTION: A color inspection device conducts a color inspection of a molded article obtained by injection molding of resin material, and the color inspection device comprises: a spectral image acquisition unit that acquires a spectral image for a plurality of spectral wavelengths for the molded article; a chromaticity calculation unit that calculates chromaticity information related to colors at a plurality of measurement points of the molded article, from the spectral image for the plurality of spectral wavelengths; and a color inspection unit that conducts the color inspection of the molded article on the basis of the chromaticity information at the plurality of measurement points.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a color inspection device and an injection molding system equipped with the color inspection device. [Background technology]

[0002] Color inspection of injection-molded resin products may be performed visually by a person or using a colorimeter (see, for example, Patent Document 1). When a person performs the color inspection visually, the inspection results are unstable due to the physical condition of the inspector and the influence of ambient light. In particular, there has been an increase in the use of recycled resin as a resin material in recent years, and injection-molded products using such recycled resin are prone to color changes such as yellowing. In the device of Patent Document 1, a spectrometer is used to measure the spectrum of an in-line part and calculate the color coordinates. A spectrometer is also used to measure the spectrum of a reference part and calculate the color coordinates. The color coordinates of a set point corresponding to the minimum concentration of master batch (colorant) at which the in-line part and the reference part cannot be distinguished by the human eye are calculated. The distance (color difference) between the color coordinates of the in-line part and the color coordinates of the set point is calculated. This enables more accurate and stable color inspection than the human eye. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-191194 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the device described in Patent Document 1, the spectrometer irradiates a spot light onto a molded product or a reference part, and measures the spectrum based on the reflected light. In this case, it is not possible to inspect the color of the molded product as a whole, and it is not possible to measure color unevenness, for example. In addition, if color unevenness occurs, the color density differs depending on the measurement point, making it difficult to measure the color density of the entire molded product. It is also possible to configure the spot light irradiation position to move within the range of the measurement target (in-line component or reference component) to scan the entire measurement target, but in this case, a separate scanning mechanism is required. Alternatively, a moving configuration is required to change the measurement position by moving the spectrometer and the measurement target relatively. However, providing a scanning mechanism or moving mechanism not only increases the cost of the device, but also increases the time required for the scanning operation or moving operation, thereby increasing the time required for color inspection and reducing production efficiency. [Means for solving the problem]

[0005] A color inspection device according to a first aspect of the present disclosure is a color inspection device that performs color inspection on a molded product obtained by injection molding a resin material, and includes a spectral image acquisition unit that acquires spectral images of the molded product at multiple spectral wavelengths, a chromaticity calculation unit that calculates chromaticity information regarding colors of multiple measurement points on the molded product from the spectral images for the multiple spectral wavelengths, and a color inspection unit that performs color inspection of the molded product based on the chromaticity information of the multiple measurement points.

[0006] An injection molding system of a second aspect of the present disclosure is an injection molding system including the color inspection device of the first aspect described above and an injection molding machine that forms the molded product by injection molding, and the injection molding machine adjusts injection molding conditions based on the color inspection results of the color inspection unit. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing a configuration of an injection molding system according to a first embodiment. [Diagram 2] 4 is a flowchart showing a color inspection method performed by the color inspection device of the first embodiment. [Diagram 3] FIG. 13 is a diagram showing an example of specifying the inspection range of a molded product. [Figure 4] FIG. 4 is a diagram showing an example of the optical spectrum of each measurement point included in the inspection range. [Diagram 5] 4A and 4B are diagrams showing an example of the reflectance spectrum of each measurement point in an inspection range, an average reflectance RAVi, and a comparative reflectance spectrum. [Figure 6] 4 is a flowchart showing a method for adjusting injection molding conditions according to the first embodiment. [Figure 7] FIG. 13 is a diagram showing an example of the color density spectrum of a molded product when the amount of master batch added is changed. [Figure 8] FIG. 8 is a diagram showing an example in which each color density spectrum in FIG. 7 is converted into chromaticity. [Figure 9] FIG. 4 is a diagram showing an example of a concentration calibration curve showing the relationship between the amount of master batch added and chromaticity. [Figure 10] FIG. 13 is a diagram showing an example of a calibration curve for color unevenness showing the relationship between the kneading adjustment parameter and color unevenness. [Figure 11] FIG. 11 is a schematic diagram showing the configuration of an injection molding system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [First embodiment] The first embodiment of the present disclosure will be described below. FIG. 1 is a schematic diagram showing the configuration of an injection molding system 1 of the first embodiment. In FIG. 1, the injection molding system 1 includes a color inspection device 10 that inspects the color of a molded product W manufactured by injection molding, and an injection molding machine 20 that manufactures the molded product W by injection molding.

[0009] [Configuration of color inspection device 10] The color inspection device 10 includes a stage 11 , a color reference body 12 , an illumination unit 13 , an imaging unit 14 , and an inspection processing unit 15 . The stage 11 is a mounting table on which the molded products W to be inspected are placed. The molded products W to be inspected may be all molded products W manufactured by the injection molding machine 20, or may be molded products W picked up at a predetermined cycle. In this embodiment, a rapid color inspection can be performed by performing a color inspection based on a spectral image, and even when all molded products W are to be inspected, it is possible to avoid a long time required for the color inspection.

[0010] The color reference body 12 has a reference color for color inspection. The reference color is, for example, white, and in this case, the light of each wavelength irradiated from the illumination unit 13 is reflected with a reflectance of 100% or approximately 100%. Note that the stage 11 may be painted in a reference color without color unevenness, and in this case, the stage 11 can function as the color reference body 12.

[0011] The illumination unit 13 irradiates illumination light onto the molded product W and the color reference body 12. White light is preferable as the illumination light. If the spectrum (emission spectrum) of the illumination light is known, the gradation value of each pixel of the spectral image can be corrected by the emission spectrum.

[0012] The imaging unit 14 is a spectroscopic camera that captures a spectroscopic image, specifically, a hyperspectral camera that can capture spectroscopic images for a plurality of spectroscopic wavelengths in the visible light range. The imaging unit 14 captures a spectroscopic image so that the entire molded product W placed on the stage 11 fits within the image. The spectroscopic image may be captured so that both the molded product W and the color reference body 12 fit within the image, or the molded product W and the color reference body 12 may be captured separately.

[0013] The inspection processing unit 15 may be, for example, a general computer such as a personal computer, a smartphone, a tablet terminal, etc. The inspection processing unit 15 controls the illumination unit 13 and the imaging unit 14, and performs color inspection processing of the molded product W based on a plurality of spectral images of the molded product W captured by the imaging unit 14. For example, the inspection processing unit 15 includes basic components of a general computer, such as a storage unit 151 configured with a memory, etc., and a processor 152 configured with a CPU, etc. The processor 152 reads and executes a program recorded in the storage unit 151, thereby functioning as a spectral image acquisition unit 152A, a range specification unit 152B, a chromaticity calculation unit 152C, a color inspection unit 152D, a pass / fail determination unit 152E, and a shape inspection unit 152F, as shown in FIG.

[0014] The spectral image acquisition unit 152A controls the illumination unit 13 and the imaging unit 14 to irradiate the molded product W and the color reference body 12 with illumination light, captures spectral images of a plurality of spectral wavelengths for the molded product W and the color reference body 12, and acquires (receives) the spectral images from the imaging unit 14. Note that, although an example in which the spectral image acquisition unit 152A controls the illumination unit 13 and the imaging unit 14 to capture the spectral images is shown here, the illumination unit 13 and the imaging unit 14 may be configured to be provided independently of the inspection processing unit 15. For example, the spectral images for the molded product W and the color reference body 12 may be captured by another spectral image capturing device and stored in a data server on the Internet, and the spectral image acquisition unit 152A may acquire the spectral images by downloading the spectral images from the data server. In addition, the acquired spectroscopic image may be subjected to various image processing such as noise reduction processing using various digital filters and pattern recognition.

[0015] The area specifying unit 152B specifies, from the spectral image, an inspection area in the molded product W. It is preferable to select a flat portion in the molded product W as the inspection area.

[0016] The chromaticity calculation unit 152C calculates chromaticity information for each measurement point by using a plurality of pixels included in the inspection range as measurement points. That is, the chromaticity calculation unit 152C calculates chromaticity information for each pixel by using each pixel value of the same pixel in the spectral images for a plurality of spectral wavelengths. For example, the chromaticity information may be calculated as a spectral spectrum (reflectance spectrum) according to the pixel value of each wavelength, or chromaticity (for example, XYZ value, Lab value, Luv value, RGB value, etc.) based on the reflectance spectrum.

[0017] Based on the chromaticity information, the color inspection unit 152D performs a color inspection of the molded product W. Specifically, the color inspection unit 152D has a color density inspection function and a color unevenness inspection function, and performs inspection of color density and inspection of color unevenness as the color inspection.

[0018] In the inspection process of color density, the color inspection unit 152D calculates the arithmetic average value of the chromaticity information of each pixel (measurement point) in the inspection range as the color density information. For example, the arithmetic average of the reflectance spectrum of all the measurement points calculated by the color inspection unit 152D is calculated, and the chromaticity based on the average reflectance spectrum is used as the color density information. Alternatively, when the chromaticity of each measurement point is calculated as the chromaticity information, the average value of each chromaticity of all the measurement points (for example, when Lab values ​​are used, the average L value, average a value, and average b value) may be calculated as the color density information.

[0019] In the inspection process for color unevenness, the color inspection unit 152D calculates the arithmetic mean (average chromaticity information) and standard deviation σ of the chromaticity information, as well as the color density information. Then, the color difference between the chromaticity information of +3σ and the average chromaticity information, or the color difference between the chromaticity information of -3σ and the average chromaticity information, is calculated as color unevenness information. For example, the average reflectance spectrum and the standard deviation σ of the reflectance spectrum are calculated. Also, the chromaticity based on the average spectral spectrum (i.e., color density information) and the chromaticity based on ±3σ are calculated. Then, the color difference between the chromaticity of the color density information and the chromaticity corresponding to ±3σ is calculated as color unevenness information.

[0020] The pass / fail determination unit 152E performs pass / fail determination of the molded product W based on the color inspection result. To determine the color density, the difference between the calculated color density information and predetermined reference density information is calculated, and it is determined whether the difference is equal to or less than a first threshold value for determining the color density. If the difference between the color density information and the reference density information is equal to or less than the first threshold value, the color density is determined to be normal, and if the difference is greater than the first threshold value, the color density is determined to be abnormal. In addition, the color unevenness is judged by judging whether the calculated color unevenness information (color difference) is equal to or greater than a predetermined second threshold. If the color unevenness information is less than the second threshold, it is judged to be normal, and if it is greater than the second threshold, it is judged to be abnormal.

[0021] The shape inspection unit 152F also functions as a foreign matter detection unit of the present disclosure, and inspects the molded product W for abnormalities in shape and the presence or absence of foreign matter based on the spectral images. The shape inspection unit 152F, for example, applies an edge detection filter or the like to the spectral image to identify the contour of the molded product W, and compares it with the external shape data of the molded product W previously stored in the memory unit 151 to inspect the molded product W for any abnormalities in its external shape or the presence or absence of foreign matter.

[0022] [Configuration of injection molding machine 20] As shown in FIG. 1, the injection molding machine 20 includes a hopper 21, a resin feed ratio adjustment section 22, a master batch feed amount adjustment section 23, a cylinder 24, a heating section 25, a screw 26, an injection section 27, a molding die 28, and an injection control section 29.

[0023] The hopper 21 is an inlet into which the resin material that is the material of the molded product W and the master batch that adjusts the color of the molded product W are charged. A recycled resin inlet, a new resin inlet, and a master batch inlet are connected to the hopper 21. The resin material and the master batch fed from the recycled resin inlet, the new resin inlet, and the master batch inlet are introduced into the cylinder 24 via the hopper 21.

[0024] The resin input ratio adjustment unit 22 adjusts the input amount of recycled resin material and the input amount of new resin material that are the materials for the molded product W, that is, adjusts the total input amount and the input ratio. The master batch input amount adjustment unit 23 adjusts the input amount of the master batch (colorant) that determines the color of the molded product W.

[0025] The cylinder 24 is a cylindrical member into which the resin material and the master batch are introduced from the hopper 21. A nozzle 241 is provided at one end of the cylinder 24 and connected to the molding die 28. An injection unit 27 is connected to the other end of the cylinder 24.

[0026] The heating unit 25 is a heater that heats and melts the resin material and the master batch introduced into the cylinder 24. The heating unit 25 is provided in the cylinder 24 and heats and melts the resin material and the master batch in the cylinder 24. In addition, for example, a pre-plunger for heating and kneading may be provided in the path from the hopper 21 to the cylinder 24. In this case, by providing a heating unit 25 to the pre-plunger, the resin material and the master batch are heated and melted before being introduced into the cylinder 24.

[0027] The screw 26 kneads the resin material and the master batch by rotating about its axis. The screw 26 is provided, for example, inside the cylinder 24, and kneads the resin material and the master batch introduced into the cylinder 24. In the configuration in which a pre-plunger is provided in the path from the hopper 21 to the cylinder 24 as described above, a screw 26 may be provided in the pre-plunger to knead the resin material and the master batch before they are introduced into the cylinder 24. In the following description, the kneaded product obtained by melting the resin material and the master batch by overheating and kneading them with the screw 26 will be referred to as a molten resin material.

[0028] The injection section 27 applies pressure to the molten resin material in the cylinder 24 from the other end of the cylinder 24 to extrude it toward the nozzle 241. For example, in a screw in-line type injection molding machine 20 in which a screw 26 is provided in the cylinder 24 as shown in FIG. 1, the injection section 27 moves the screw 26 forward and backward along the axial direction within the cylinder 24. As a result, the molten resin material extruded by the screw 26 is injected into the molding die 28 from the nozzle 241. In addition, in the case where a pre-plunger is provided in the path from the hopper 21 to the cylinder 24, the injection section 27 moves an injection ram inserted into the cylinder 24 back and forth within the cylinder 24. The molding die 28 is a metal mold corresponding to the shape of the molded product W, and the molded product W is formed by introducing the molten resin injected from the cylinder 24 into the molding die 28. In addition, the hopper 21, resin feeding ratio adjustment section 22, master batch feeding amount adjustment section 23, cylinder 24, heating section 25, screw 26, injection section 27, and molding die 28 may constitute one lot, and the injection molding machine 20 may be configured to have multiple lots.

[0029] The injection control unit 29 controls the resin input ratio adjustment unit 22, the master batch input amount adjustment unit 23, the heating unit 25, the screw 26, and the injection unit 27. Specifically, the injection control unit 29 includes a reference molding control unit 291, a concentration adjustment control unit 292, a color unevenness adjustment control unit 293, and a molding machine side memory unit 294. The reference molding control unit 291 sets default molding conditions based on the reference conditions set according to the molded product W to be molded. That is, the reference molding control unit 291 sets the input ratio and total input amount of the recycled resin material and the new resin material, the input amount of the master batch, the heating temperature (plasticization temperature) by the heating unit 25, the screw rotation speed of the screw 26, and the injection pressure (e.g., injection speed and injection amount) of the molten resin material to be injected by the injection unit 27. The concentration adjustment control unit 292 adjusts the input amount of at least one of the recycled resin material, the new resin material, and the master batch according to color concentration information that is the color inspection result from the color inspection device 10. The color unevenness adjustment control unit 293 adjusts the plasticization temperature, the screw rotation speed, the residence time of the molten resin in the cylinder 24 (i.e., the mixing time of the resin material and master batch by the screw 26), and the injection pressure of the molten resin material according to the color unevenness information, which is the color inspection result by the color inspection device 10.

[0030] [Color inspection method for injection molding system 1] Next, the color inspection method in the injection molding system 1 will be described in more detail. FIG. 2 is a flowchart showing a color inspection method using the color inspection device 10. The color inspection method using the color inspection device 10 performs color inspection on a molded product W molded by the injection molding machine 20 of the injection molding system 1 as an inspection object. The molded articles W to be inspected may be selected randomly at any timing as described above, or all of the molded articles W may be inspected. First, the molded product W to be inspected is picked up and placed on the stage 11, and the molded product W is illuminated by the illumination unit 13 (step S1).Then, the spectral image acquisition unit 152A controls the imaging unit 14 to capture spectral images for a plurality of spectral wavelengths (step S2). At this time, a spectral image for the color reference body 12 is also captured at the same time. In step S2, when capturing each spectral image, the relative positions of the imaging unit 14 and the molded product W are fixed and imaging processing is performed.

[0031] Next, the area specifying unit 152B specifies the inspection area of ​​the molded product W in each of the spectral images (step S3). FIG. 3 is a diagram showing an example of specifying the inspection range of the molded product W. For example, the range specifying unit 152B specifies an edge W1 (contour portion) of the molded product W by edge detection processing, and sets the inside of the edge W1 as the inspection range Ws. Also, as shown in FIG. 3, when another closed edge W2 is detected inside the closed edge W1, the inspection range Ws between the edges W1 and W2 may be specified. Note that the edges W1 and W2 are points where the luminance value changes significantly, so when these edges W1 and W2 are inspected, the accuracy of the color inspection is affected. For this reason, as shown in FIG. 3, the inspection range may be specified by connecting points (edge ​​W3 in FIG. 3) that are a predetermined distance away from the edges W1 and W2. Alternatively, the inspection range may be configured so that the user can specify the inspection range.

[0032] Next, the chromaticity calculation unit 152C calculates chromaticity information by using each pixel in the inspection range Ws specified in step S3 as a measurement point (step S4). FIG. 4 is a diagram showing an example of the optical spectrum at each measurement point. For example, in this embodiment, the pixel positions (x, y) of the spectral image are set as measurement points, and the spectral wavelength λ at each measurement point (x, y) is i Reflectance R(x,y,λ i ) is the brightness value r i (x, y) and the spectral wavelength λ of the color reference body 12 i Luminance value r for b Based on this, R(x,y,λ i )=r i (x,y) / r bHere, i is a variable specifying the spectral wavelength, and is an integer between 1 and I. For example, when capturing a spectral image at spectral wavelengths in 20 nm intervals for a visible light range of 400 nm to 700 nm, I=16. As a result, the spectral spectrum (reflectance spectrum) at each measurement point can be calculated as chromaticity information, as shown in FIG. 4.

[0033] Next, the color inspection unit 152D performs a color inspection based on the chromaticity information of each measurement point in the inspection range calculated in step S4. Specifically, in this embodiment, the color inspection unit 152D performs an inspection of the color density and color unevenness of the molded product W as the color inspection. In order to inspect the color density, the color inspection unit 152D measures the average reflectance R, which is the arithmetic mean of the reflectances R at the respective measurement points. AVi (Average chromaticity information) is calculated by the following formula (1) (step S5).

[0034]

number

[0035] Here, n is the number of measurement points included in the inspection range. Then, the color inspection unit 152D detects the spectral wavelengths λ of a plurality of measurement points included in the inspection range. i Average reflectance R AVi Based on this, predetermined chromaticity (for example, L*, a*, b* in this embodiment) is calculated and used as color density information (step S6).

[0036] Thereafter, the pass / fail determination unit 152E determines whether or not there is an abnormality in the color density based on the calculated color density information (step S7). For example, the pass / fail determination unit 152E calculates the difference (density difference) between the reference density information set for each molded product W and the calculated color density information, and determines that the molded product W is pass if the density difference is less than a first threshold value, and determines that the molded product W is fail if the density difference is equal to or greater than the first threshold value. Furthermore, the pass / fail determination unit 152E may perform control to display the pass / fail determination result and the density difference on a display (not shown).

[0037] In this embodiment, in steps S4 to S6, an example is shown in which L*a*b* values ​​are calculated as color density information, but other chromaticities may also be calculated. For example, Lab values, Luv values, tristimulus values ​​XYZ, RGB values, yellowness, etc. may be calculated as chromaticities. For example, when the pass / fail judgment of the color density is performed based on the yellowing degree, the color inspection unit 152D uses the average reflectance R AVi Among them, the spectral wavelength λ of the visible light region i (e.g., 380 nm to 680 nm) and calculates tristimulus values ​​(XZY values) using a known method such as that specified in JIS Z 8722. In step S6, the color inspection unit 152D calculates yellowness YI from the calculated tristimulus values ​​using a known method such as that specified in JIS Z 7373, and sets it as color concentration information. The pass / fail determination unit 152E calculates the difference between a reference yellowness YI0 (reference concentration information) that is set in advance for the molded product W and stored in the storage unit 151 and the calculated yellowness YI as a yellowness ΔYI, and determines whether the yellowness ΔYI is equal to or greater than a predetermined first threshold value.

[0038] In this embodiment, in step S4, the chromaticity calculation unit 152C calculates the reflectance R of each measurement point as chromaticity information, and in step S5, the color inspection unit 152D calculates the average reflectance R AVi is calculated as the average chromaticity information, and in step S6, the color inspection unit 152D calculates the average reflectance R AVi to various chromaticities to obtain color density information, but the present invention is not limited to this. For example, the chromaticity calculation unit 152C may calculate other chromaticity information as the chromaticity information of each measurement point, and the color inspection unit 152D may calculate the arithmetic mean of the chromaticity information as the color density information. For example, in step S4, the chromaticity calculation unit 152C may calculate the Lab value of each measurement point as the chromaticity information, and in step S5, the color inspection unit 152D may calculate the average Lab value, which is the arithmetic mean, as the color density information. In this case, the conversion process in step S6 can be omitted.

[0039] If the answer in step S7 is YES, that is, if there is no abnormality in the color density of the molded product W, the color density information is stored in the storage unit 151, and the process proceeds to step S9. If the answer in step S7 is NO, that is, if there is an abnormality in the color density of the molded product W, the color density information is output to the injection control unit 29 of the injection molding machine 20 (step S8), and the process proceeds to the inspection of color unevenness in step S9. As a result, the molding conditions of the molded product W are adjusted by the injection control unit 29. The operation of changing the molding conditions will be described later.

[0040] In the inspection for color unevenness, color inspection unit 152D calculates the average chromaticity information and the standard deviation σ of each measurement point in the inspection range (step S9). The calculation of the average chromaticity information is the same as in step S5. In this embodiment, the inspection of color unevenness in step S9 and thereafter is performed after the inspection of color density in steps S5 to S8. Therefore, the average chromaticity information (average reflectance R AVi Note that a color unevenness inspection may be performed before the color density inspections in steps S5 to S8, and in this case, average chromaticity information is calculated in step S9 in the same manner as in step S5. In step S9, the average reflectance R AVi In addition, the standard deviation σ is further calculated.

[0041] Next, the color inspection unit 152D calculates the standard deviation σ and the average reflectance R AVi From this, the comparative reflectance spectrum (average reflectance R AVi ±3σ) is calculated (step S10). FIG. 5 shows the reflectance spectrum of each measurement point in the inspection area and the average reflectance R AVi 13A and 13B are diagrams illustrating an example of a comparative reflectance spectrum. Next, the chromaticity (for example, in this embodiment, L*, a*, b*) corresponding to the comparative reflectance spectrum is calculated, and color density information (i.e., the average reflectance R AVi The difference between the chromaticity corresponding to the chromaticity is calculated and used as color unevenness information (step S11). Note that color inspection unit 152D may adopt either the color difference between the chromaticity and color density information corresponding to the comparative reflectance spectrum of +3σ or the color difference between the chromaticity and color density information corresponding to the comparative reflectance spectrum of -3σ as the color unevenness information. Alternatively, color inspection unit 152D may adopt the color difference between the chromaticity and color density information corresponding to the comparative reflectance spectrum of +3σ or the color difference between the chromaticity and color density information corresponding to the comparative reflectance spectrum of -3σ, whichever has a larger color difference, as the color unevenness information.

[0042] Thereafter, the pass / fail determination unit 152E determines whether or not there is an abnormality in color unevenness based on the calculated color unevenness information (step S12). For example, the pass / fail determination unit 152E calculates the difference (color unevenness evaluation value) between the reference color unevenness information set for each molded product W and the color unevenness information calculated in step S11, and determines that the molded product is pass if the color unevenness evaluation value is less than a second threshold value, and that the molded product is fail if the color unevenness evaluation value is equal to or greater than the second threshold value.

[0043] The inspection of color unevenness is not limited to the above-mentioned one that uses the calculation of ±3σ. For example, the color inspection unit 152D may calculate the chromaticity of each measurement point in the inspection range, that is, the reflectance R(x, y, λ i ) converted to chromaticity such as L*a*b* values ​​and color density information (i.e., average reflectance R AVi The color difference between the measured color difference (chromaticity corresponding to the measured color difference) and the measured color difference (chromaticity corresponding to the measured color difference) may be calculated. In this case, the color inspection unit 152D may further determine whether or not the color difference exceeds a predetermined allowable color difference, and may treat the number of measurement points that exceed the allowable color difference or the ratio of measurement points that exceed the allowable color difference to all measurement points in the inspection range as color unevenness information. When using such color unevenness information, the pass / fail judgment unit 152E judges whether or not the color unevenness information is equal to or greater than a predetermined second threshold value. Similarly to the inspection of color density, the pass / fail judgment unit 152E may control the display of the pass / fail judgment result and color unevenness information on a display (not shown). In this case, as described above, when judging color unevenness based on the color difference between the chromaticity of each measurement point and the color density information, a color unevenness judgment image in which measurement points that exceed the allowable color difference are mapped and clearly indicated may be displayed on the image of the molded product W.

[0044] If the answer is YES in step S12, that is, if there is no abnormality in the color unevenness of the molded product W, the color unevenness information is stored in the storage unit 151, and the color inspection process ends. If it is determined that there is no abnormality in both steps S7 and S12, it is determined that the molding conditions of the injection molding machine 20 are optimal, and the current injection molding conditions are maintained to continue the production of the molded product W by the injection molding machine 20. On the other hand, if the result of step S12 is NO, that is, if there is an abnormality in the color unevenness of the molded product W, the color unevenness information is output to the injection control unit 29 of the injection molding machine 20 (step S13). As a result, if the result of either step S7 or step S12 is NO, the molding conditions of the molded product W are adjusted by the injection control unit 29.

[0045] In this embodiment, the shape inspection unit 152F of the color inspection device 10 performs a shape inspection of the molded product W based on the spectral image acquired in step S2 (step S14). The timing of the shape inspection is illustrated as being after the inspection of color density and color unevenness in steps S4 to S13, but may be after step S2 or step S3. The shape inspection unit 152F performs edge detection processing on the spectral image, for example, as in step S3, to detect edges W1 and W2 of the molded product W, and compares them with the external shape data (reference data) of the molded product W previously recorded in the storage unit 151. If the shapes of the edges W1 and W2 are different from the external shape data, it is determined that the shape of the molded product W is abnormal, and if an edge different from the edges W1 and W2 is detected, it is determined that a foreign object is present. The shape inspection result of the shape inspection unit 152F may be displayed on a display as appropriate.

[0046] [Adjustment of molding conditions of injection molding machine 20] In the injection molding system 1 of this embodiment, if the result of either step S7 or step S12 is NO, the molding conditions of the molded product W are adjusted to eliminate color density and color unevenness. If the injection molding system 1 has multiple lots, the molded products W molded in each lot are inspected by the color inspection device 10, and the molding conditions for each lot are individually adjusted based on the respective color inspection results. FIG. 6 is a flowchart showing a method for adjusting the injection molding conditions.

[0047] When the injection control unit 29 receives the color inspection result from the color inspection device 10 (step S21), it determines whether or not the received color inspection result includes color density information (step S22). When the result of the determination in step S22 is YES, that is, when the molded product W is determined to have an abnormality in color density, the concentration adjustment control unit 292 of the injection control unit 29 adjusts the molding conditions of at least one of the resin input ratio adjustment unit 22 and the master batch input amount adjustment unit 23 (step S23). For example, the concentration adjustment control unit 292 adjusts the input amount of the master batch while maintaining the input amounts of the recycled resin material and the new resin material input from the resin input ratio adjustment unit 22 constant. The concentration adjustment control unit 292 may adjust the input amount of the recycled resin material while maintaining the input amounts of the master batch and the new resin material. The concentration adjustment control unit 292 may adjust the input amount of the new resin material while maintaining the input amounts of the master batch and the recycled resin material. The concentration adjustment control unit 292 may adjust all or a plurality of the input amounts of the master batch, the recycled resin material, and the new resin material.

[0048] Here, the adjustment of the amount of master batch added will be described as an example. Fig. 7 is a diagram showing an example of the color density spectrum of the molded product W when the amount of the master batch is changed while the ratio of the recycled resin material and the new resin material is kept constant. Fig. 8 is a diagram showing an example of the color density spectrum of Fig. 7 converted into chromaticity. Fig. 9 is a diagram showing an example of a concentration calibration curve showing the relationship between the amount of the master batch and chromaticity.

[0049] The example shown in Figure 7 shows the average reflectance R of molded product W when the amount of masterbatch added is different. AVi 7, by changing the amount of masterbatch input, the overall color concentration spectrum of the molded product W changes. Note that, here, in Fig. 7 to Fig. 9, the amount of masterbatch input indicates a ratio to the reference input amount of masterbatch for molding the molded product W, which is set by the reference molding control unit 291, but is not limited to this. For example, the input amount may be the mass, volume, etc. of the masterbatch to be input. By converting each color density spectrum as shown in Fig. 7 into a predetermined chromaticity, it is possible to obtain a chromaticity as shown in Fig. 8. Note that, although a* value and b* value are shown as an example of chromaticity in Fig. 8, this is not limiting. For example, an L* value, a color difference ΔE from reference density information, a reflectance or transmittance at a predetermined characteristic wavelength (e.g., a wavelength having a maximum or minimum in a reflectance spectrum), an average reflectance or average transmittance over the entire wavelength, etc. may be used. By measuring in advance the difference in chromaticity depending on the amount of master batch added as in Fig. 8, it is possible to create a calibration curve (calibration curve for concentration) showing the relationship between the amount of master batch added and the chromaticity as in Fig. 9. In this embodiment, such a calibration curve for concentration is created in advance and stored in the molding machine side storage unit 294.

[0050] FIG. 9 shows a concentration calibration curve indicating the relationship between the amount of master batch added and the b* value, with the b* value being the chromaticity. However, the a* value may also be used as the chromaticity, or the above-mentioned L* value, color difference ΔE, reflectance or transmittance at a characteristic wavelength, average reflectance or average transmittance, etc. may also be used. 9 is a concentration calibration curve in which the b* value is the chromaticity parameter and the amount of masterbatch input is the molding condition (input condition parameter), but the input condition parameter may be other conditions. For example, in the case where the amount of masterbatch input is fixed and the input ratio of recycled resin material to new resin material is adjusted, a concentration calibration curve can be created in which the input amount of recycled resin material or the input amount of new resin material is used as the input condition parameter instead of the input amount of masterbatch. Furthermore, multiple chromaticity parameters may be used as the chromaticity parameters. For example, concentration calibration curves showing the relationship between the a* value, the b* value, and the L* value and the input condition parameters (e.g., the input amount of the master batch) may be prepared. Furthermore, a concentration calibration curve showing the relationship between a plurality of chromaticity parameters and a plurality of input condition parameters may be prepared. In the example of FIG. 9, the concentration calibration curve is an approximate straight line, but it may be a higher-order function or another curved line.

[0051] In step S23, the concentration adjustment control unit 292 adjusts the amount of master batch input based on the color concentration information input from the color inspection device 10 and the concentration calibration curve stored in the molding machine side storage unit 294 so that the difference between the color concentration information and the reference concentration information is less than the first threshold value. For example, the concentration adjustment control unit 292 calculates the master batch adjustment amount corresponding to the concentration difference between the color concentration information and the reference concentration information based on the concentration calibration curve. Then, the concentration adjustment control unit 292 sets a new master batch input amount by adding or subtracting the calculated master batch adjustment amount to or from the current master batch input amount (for example, the input amount set by the reference molding control unit 291), and outputs a command signal to the master batch input amount adjustment unit 23 to input the set master batch input amount. As a result, the master batch input amount adjustment unit 23 adjusts the master batch input amount. The above is an example of adjusting the input amount of the master batch, but as described above, when adjusting the input amounts of recycled resin material and new resin material, the concentration adjustment control unit 292 only needs to output a command signal to the resin input ratio adjustment unit 22 to specify the input ratio of the resin materials. As a result, the resin input ratio adjustment unit 22 adjusts the input amounts of the recycled resin material and new resin material based on the input ratio of the recycled resin material and new resin material.

[0052] After step S23, or if the result of the determination in step S22 is NO, the injection control unit 29 determines whether or not color unevenness information is included in the color inspection result received in step S21 (step S24). If the answer is YES in step S24, that is, if it is determined that the molded product W has an abnormality in color unevenness, the color unevenness adjustment control unit 293 of the injection control unit 29 adjusts at least one of the molding conditions, namely, the plasticization temperature, the screw rotation speed, the residence time, and the injection pressure (step S25). For example, the color unevenness adjustment control section 293 may adjust one of the molding conditions (kneading adjustment parameters) for determining color unevenness and fix the other parameters, or may adjust a plurality of kneading adjustment parameters.

[0053] The adjustment of the kneading adjustment parameters is substantially the same as the adjustment of the color concentration. For example, when the kneading adjustment parameter is the screw rotation speed, the plasticization temperature, the residence time, and the injection pressure are kept constant, and the molded product W is molded while the screw rotation speed is changed, and the color unevenness information of the molded product W corresponding to each screw rotation speed is calculated. Then, a color unevenness calibration curve showing the relationship between the screw rotation speed and the color unevenness information is generated and stored in advance in the molding machine side storage unit 294. FIG. 10 is an example of a calibration curve for color unevenness showing the relationship between the kneading adjustment parameters and color unevenness. In the above example, the kneading adjustment parameter was the screw rotation speed, but as described above, it may be any one of the plasticization temperature, residence time, and injection pressure, or it may show a relationship with multiple kneading adjustment parameters. In the example of FIG. 10, the color unevenness calibration curve is an approximation line, but it may be a higher-order function or other curved line.

[0054] In step S25, the color unevenness adjustment control unit 293 adjusts the kneading adjustment parameters (e.g., screw rotation speed) based on the color unevenness information input from the color inspection device 10 and the color unevenness calibration curve stored in the molding machine side storage unit 294 so that the difference between the color unevenness information and the reference color unevenness information (color unevenness evaluation value) is less than a second threshold value. For example, the color unevenness adjustment control unit 293 calculates the screw acceleration / increase speed corresponding to the color unevenness evaluation value based on the dark unevenness calibration curve, and adds the calculated screw acceleration / increase speed to the current screw rotation speed to set a new screw rotation speed. In addition, the color unevenness adjustment control unit 293 resets the rotation speed of the screw 26 to the set screw rotation speed. This improves the kneading performance of the screw 26 and improves color unevenness. While the above is an example of adjusting the screw rotation speed, when adjusting the plasticization temperature, the color unevenness adjustment control unit 293 adjusts the heating temperature in the heating unit 25. When adjusting the residence time, the color unevenness adjustment control unit 293 adjusts the injection interval of the molten resin by the injection unit 27. When adjusting the injection pressure, the color unevenness adjustment control unit 293 adjusts the injection speed and injection amount of the molten resin by the injection unit 27.

[0055] [Effects of this embodiment] The injection molding system 1 of this embodiment includes a color inspection device 10 that performs color inspection of a molded product obtained by injection molding a resin material. The processor 152 of the color inspection device 10 functions as a spectral image acquisition unit 152A, a chromaticity calculation unit 152C, and a color inspection unit 152D. The spectral image acquisition unit 152A acquires spectral images of the molded product W at multiple spectral wavelengths. The chromaticity calculation unit 152C calculates chromaticity information related to colors at multiple measurement points of the molded product W from the spectral images at the multiple spectral wavelengths. The color inspection unit 152D performs color inspection of the molded product W based on the chromaticity information of the multiple measurement points.

[0056] In this embodiment, color inspection of the molded product W is performed based on a spectral image capturing the entire molded product W. Therefore, compared to measuring one point on the molded product W using spot light, it is possible to properly measure the overall color density and color unevenness of the molded product W. Also, compared to scanning the molded product W by changing the irradiation position of the spot light using a scanning mechanism, or changing the measurement position by moving the relative position between the spot light and the molded product W using a moving mechanism, it is possible to simplify the configuration.

[0057] In the color inspection device 10 of this embodiment, the processor 152 also functions as a range specification unit 152B that specifies the image range of the molded product W included in the spectral image as the inspection range. The chromaticity calculation unit 152C calculates chromaticity information of each measurement point by using pixels included in the inspection range as measurement points. The color inspection unit 152D calculates the arithmetic mean of the chromaticity information of each measurement point as average chromaticity information, and calculates color density information of each color based on the average chromaticity information. By using pixels included in the inspection range as measurement points, it is possible to calculate chromaticity information for each position over a wide range of the molded product W. By calculating the arithmetic average of this chromaticity information, it is possible to obtain overall color density information for the molded product W. In other words, when measuring a single point using a spot light, if color unevenness occurs, it is not possible to determine the correct color density of the molded product W. In contrast, the arithmetic average of chromaticity information from multiple points on the molded product W is a value that indicates the overall density trend of the molded product W, making it possible to properly inspect the overall color density of the molded product W.

[0058] In this embodiment, the color inspection unit 152D also detects the average reflectance R AVi The yellowness index YI of the molded article W may be calculated from the above. In this case, the yellowing degree ΔYI can be calculated based on the calculated yellowing degree YI and the reference yellowing degree YI0. In injection molding using a resin material containing recycled resin material, the molded product W may turn yellow due to deterioration of the recycled resin material. In contrast, in this embodiment, the yellowing degree can be calculated based on the yellowing degree, and the specific yellowing of the molded product W using the resin material can be suitably detected.

[0059] In this embodiment, the color inspection unit 152D measures the average reflectance R AVi (average chromaticity information) and standard deviation σ. Also, the color inspection unit 152D calculates the average reflectance R AVi The chromaticity based on the comparative reflectance spectrum with 3σ added to the average reflectance R AVi The color difference based on the chromaticity and the average reflectance R AVi The chromaticity based on the comparative reflectance spectrum with 3σ subtracted from the average reflectance R AVi At least one of the color differences between the chromaticity based on the above is calculated as color unevenness information. As described above, by using pixels included in the inspection range as measurement points, it is possible to calculate chromaticity information for each position over a wide range of the molded product W. In addition, if the molded product W has color unevenness, the 3σ value will also be large. Therefore, if the color unevenness is large, the average reflectance R AVi The chromaticity corresponding to the comparative reflectance spectrum obtained by adding or subtracting 3σ to the average reflectance R AVi The color difference with the chromaticity corresponding to also becomes large, and by calculating this color difference as color unevenness information, the presence or absence of color unevenness in the molded product W can be appropriately determined.

[0060] In this embodiment, the processor 152 also functions as a pass / fail determination section 152E that determines whether the molded product W is a non-defective product based on the color inspection result in the color inspection section 152D. This makes it possible to easily determine whether the molded product W has color density abnormalities or color unevenness abnormalities.

[0061] The injection molding system 1 of this embodiment includes a color inspection device 10 as described above, and an injection molding machine 20 that forms a molded product W by injection molding, and the injection molding machine 20 adjusts the injection molding conditions based on the color inspection results of the color inspection section 152D. As a result, when color density or color unevenness occurs, the molding conditions can be adjusted in the injection molding machine 20 based on the color density inspection results or color unevenness inspection results, thereby reducing the rate of defective molded products W molded by the injection molding machine 20.

[0062] In this embodiment, the injection molding machine 20 has a hopper 21 into which recycled resin material, new resin material, and master batch are charged, a resin charging ratio adjustment unit 22 that adjusts the charging ratio of the recycled resin material and new resin material charged into the hopper 21, and a master batch charging amount adjustment unit 23 that adjusts the charging amount of the master batch charged into the hopper 21. Then, an injection control unit 29 of the injection molding machine 20 adjusts at least one of the resin charging ratio and the charging amount of the master batch based on color concentration information input from the color inspection device 10. This allows the input amount of at least one of the recycled resin material, the new resin material, and the master batch to be adjusted based on the color density information, making it possible to mold a molded product W with an appropriate color density. In cases where it is difficult to adjust the color density of the molded product W using only one of the recycled resin material, the new resin material, and the master batch, it is also possible to adjust the input amounts of multiple or all of the recycled resin material, the new resin material, and the master batch, making it possible to mold a molded product W with a desired color density.

[0063] In this embodiment, the injection molding machine 20 has a cylinder 24 to which the resin material and master batch input from the hopper 21 are sent, a heating section 25 that heats and plasticizes the resin material and master batch in the cylinder 24, a screw 26 that is inserted into the cylinder 24 to knead the resin material and master batch and has an adjustable rotation speed, and an injection section 27 that extrudes the kneaded product of the resin material and master batch in the cylinder 24. An injection control section 29 of the injection molding machine 20 adjusts at least one of the plasticization temperature by the heating section 25, the screw rotation speed of the screw 26, the kneading time (residence time) in the cylinder 24, and the injection pressure in the injection section 27, based on the color unevenness information input from the color inspection device 10. This allows at least one of the plasticization temperature, the screw rotation speed, the residence time, and the injection pressure to be adjusted based on the color unevenness information, making it possible to mold a molded article W that is free of color unevenness (i.e., color unevenness that is not noticeable to the human eye). Also, in cases where it is difficult to adjust the color unevenness of the molded article W using only one of the plasticization temperature, the screw rotation speed, the residence time, and the injection pressure, it is also possible to adjust multiple or all of the plasticization temperature, the screw rotation speed, the residence time, and the injection pressure, making it possible to mold a molded article W that is free of color unevenness.

[0064] In this embodiment, the processor 152 of the color inspection device 10 also functions as a shape inspection unit 152F, and inspects the molded product W for foreign matter and shape abnormalities based on the spectral images. This makes it possible to detect not only abnormalities in color density and color unevenness, but also abnormalities in the shape of the molded product W and foreign objects.

[0065] [Second embodiment] Next, a second embodiment will be described. In the first embodiment, an example was shown in which, when the molded product W is determined to be defective by the pass / fail judgment of the molded product W, the molding conditions of the injection molding machine 20 are adjusted. In contrast, in the present embodiment, a rank judgment of the molded product W is performed, which is different from the first embodiment. In the following description, items that have already been described will be given the same reference numerals, and description thereof will be omitted or simplified.

[0066] FIG. 11 is a block diagram showing a schematic configuration of an injection molding system 1A of the second embodiment. In this embodiment, similarly to the first embodiment, the color inspection device 10A includes a stage 11, a color reference body 12, an illumination unit 13, an imaging unit 14, and an inspection processing unit 15, and the inspection processing unit 15 includes a storage unit 151 and a processor 152. The processor 152 in this embodiment functions as a rank determination unit 152G instead of the pass / fail determination unit 152E.

[0067] The rank determining section 152G determines the rank of the molded product W based on the color inspection result. The color density rank is determined by determining which of a plurality of preset density rank ranges the density difference between the calculated color density information and the predetermined reference density information falls into. For example, a molded product W whose density difference is less than a first threshold value is classified as density rank A. A molded product W whose density difference is equal to or greater than the first threshold value and less than a predetermined first density upper limit value is classified as density rank B. A molded product W whose density difference is equal to or greater than the first density upper limit value and less than a predetermined second density upper limit value is classified as density rank C. The ranges of density differences for the subsequent density ranks are similarly set in advance, and the molded product W is classified into the corresponding density rank according to its density difference.

[0068] Similarly, in determining the rank of color unevenness, it is determined which of a plurality of preset color unevenness rank ranges the color unevenness information (color difference) falls into. For example, a molded product W whose color unevenness information is less than a second threshold value is classified as color unevenness rank A. A molded product W whose color unevenness information is equal to or greater than the second threshold value and less than a predetermined first unevenness upper limit value is classified as color unevenness rank B. A molded product W whose concentration difference is equal to or greater than the first unevenness upper limit value and less than a predetermined second unevenness upper limit value is classified as color unevenness rank C. The ranges of color unevenness information for the subsequent color unevenness ranks are similarly preset, and the molded product W is classified into the corresponding color unevenness rank according to its color unevenness information.

[0069] Moreover, the configuration of the injection molding machine 20 in this embodiment is similar to that in the first embodiment. In this embodiment, the injection control unit 29 may receive density rank and color unevenness rank as color inspection results input from the color inspection device 10, and adjust the molding conditions for the molded product W according to the density rank and color unevenness rank. For example, for the concentration rank B and onward, the adjustment amount of the molding conditions for each concentration rank may be stored in advance in the molding machine side storage unit 294. The molding conditions are conditions for classifying the concentration difference of the molded product W into the concentration rank A, and for example, molding conditions for the upper limit values ​​of each concentration rank (a first concentration upper limit value for the concentration rank B, and a second concentration upper limit value for the concentration rank C) may be set. The same applies to molding conditions for color unevenness ranks, and for example, it is preferable that the adjustment amount of the molding conditions for each color unevenness rank is stored in advance in the molding machine side storage unit 294. The molding conditions are conditions for classifying the color unevenness information of the molded product W into color unevenness rank A, and for example, molding conditions for the upper limit value of each color unevenness rank (first color unevenness upper limit value for color unevenness rank B, and second color unevenness upper limit value for color unevenness rank C) may be set.

[0070] [Effects of this embodiment] In this embodiment, the same effects as those of the first embodiment described above can be obtained. In addition, in this embodiment, the processor 152 also functions as a rank determining section 152G that ranks the quality of the molded product W based on the color inspection result in the color inspection section 152D. This makes it possible to easily determine the grade indicating whether the injection-molded product W is good or bad. When the rank of the molded product W is determined in this manner, the molding conditions during injection molding in the injection molding machine 20 can be adjusted according to the determined rank. In other words, it is only necessary to switch the molding conditions according to the rank, and the adjustment of the molding conditions in the injection molding machine 20 can be quickly and easily performed.

[0071] [Variations] The present invention is not limited to the above-described embodiments, and the present invention includes configurations obtained by modifying, improving, and appropriately combining the embodiments within the scope that can achieve the object of the present invention.

[0072] (Variation 1) In the first and second embodiments, an example is shown in which the color inspection device 10 inspects both color density and color unevenness, but it may also be configured to inspect only color density or only color unevenness.

[0073] (Variation 2) The chromaticity calculation unit 152C calculates the reflectance R(x, y, λ) of each measurement point. i ) and the color inspection unit 152D calculates the average reflectance R AViCalculate the average reflectance R AVi into various chromaticities such as L*a*b* values ​​to calculate color density information and color unevenness information, but the present invention is not limited to this. As described above, the chromaticity calculation unit 152C may calculate chromaticities such as L*a*b* values ​​as chromaticity information of each measurement point, and the color inspection unit 152D may calculate an average chromaticity value of each measurement point.

[0074] (Variation 3) In the first embodiment, an example was shown in which the processor 152 of the color inspection device 10 functions as the shape inspection unit 152F, but the injection control unit 29 of the injection molding machine 20 may be configured to acquire spectral images from the color inspection device 10 and inspect for the presence or absence of foreign matter and shape abnormalities.

[0075] (Variation 4) In the first embodiment, a color inspection device 10 having a pass / fail judgment unit 152E is illustrated, and in the second embodiment, a color inspection device 10A having a rank judgment unit 152G is illustrated, but the color inspection device 10 of the first embodiment may be configured to include both the pass / fail judgment unit 152E and the rank judgment unit 152G.

[0076] [Summary of this disclosure] A color inspection device according to a first aspect of the present disclosure is a color inspection device that performs color inspection on a molded product obtained by injection molding a resin material, and includes a spectral image acquisition unit that acquires spectral images of the molded product at multiple spectral wavelengths, a chromaticity calculation unit that calculates chromaticity information regarding colors of multiple measurement points on the molded product from the spectral images for the multiple spectral wavelengths, and a color inspection unit that performs color inspection of the molded product based on the chromaticity information of the multiple measurement points.

[0077] In the color inspection device of this embodiment, the color inspection of the molded product is performed based on a spectral image of the entire molded product. Therefore, the color density and color unevenness of the entire molded product can be measured more appropriately than when one point on the molded product is measured using a spot light. In addition, the configuration can be simplified compared to when the molded product is scanned by changing the irradiation position of the spot light using a scanning mechanism, or when the measurement position is changed by moving the relative position between the spot light and the molded product using a moving mechanism.

[0078] In the color inspection device of this embodiment, it is preferable that the device further includes a range identification unit that identifies an image range of the molded product included in the spectral image as an inspection range, the chromaticity calculation unit calculates chromaticity information for each of the measurement points by using pixels included in the inspection range as the measurement points, and the color inspection unit calculates an arithmetic mean of the chromaticity information for each of the measurement points as average chromaticity information, and calculates color density information for each color based on the average chromaticity information.

[0079] This allows the chromaticity information of each position over a wide area of ​​the molded product to be calculated by using pixels included in the inspection range as measurement points. By calculating the arithmetic mean of this chromaticity information, the color density information of the entire molded product can be obtained.

[0080] In the color inspection device of this aspect, it is preferable that the color inspection section calculates a yellowness index of the molded article from the average chromaticity information as the color density information. This makes it possible to detect the yellowing that is characteristic of resin molded products.

[0081] In the color inspection device of this embodiment, it is preferable that the device includes a range identification unit that identifies an image range of the molded product included in the spectral image as an inspection range, and the chromaticity calculation unit calculates chromaticity information for each of the measurement points by using pixels included in the inspection range as the measurement points, and the color inspection unit calculates average chromaticity information, which is the arithmetic mean of the chromaticity information for each of the measurement points, and σ, which is the standard deviation, and calculates, as color unevenness information, the color difference between the chromaticity information obtained by adding 3σ to the average chromaticity information and the average chromaticity information, and the color difference between the chromaticity information obtained by subtracting 3σ from the average chromaticity information and the average chromaticity information.

[0082] This makes it possible to calculate chromaticity information for each position over a wide range of the molded product by using pixels included in the inspection range as measurement points. Furthermore, if the molded product has color unevenness, the 3σ value will also be large. Therefore, if the color unevenness is large, the color difference (color unevenness information) between the chromaticity information obtained by adding or subtracting 3σ to the average chromaticity information and the average chromaticity information will also be large. Therefore, the presence or absence of color unevenness in the molded product can be properly determined based on the color unevenness information.

[0083] In the color inspection device of this aspect, it is preferable to further include a pass / fail judgment section that judges whether the molded product is a non-defective product based on a color inspection result in the color inspection section. This makes it possible to judge whether a molded product is pass or fail based on abnormalities in color density and color unevenness.

[0084] In the color inspection device of this aspect, it is preferable to further include a rank determining unit that ranks the quality of the molded product based on a color inspection result in the color inspection unit. This makes it possible to rank the quality of the molded product based on abnormalities in color density and color unevenness.

[0085] An injection molding system of a second aspect of the present disclosure is an injection molding system including the color inspection device of the first aspect described above and an injection molding machine that forms the molded product by injection molding, and the injection molding machine adjusts injection molding conditions based on the color inspection results of the color inspection unit. This allows the injection molding conditions to be adjusted based on the color inspection results from the color inspection device so that abnormalities in color density and color unevenness are not generated, thereby improving the quality of molded products produced by the injection molding machine.

[0086] In the injection molding system of this embodiment, the color inspection unit calculates color concentration information for each color of the molded product, and the injection molding machine has a hopper into which recycled resin material, new resin material, and master batch are fed, a resin feeding ratio adjustment unit that adjusts the feeding ratio of the recycled resin material and the new resin material fed into the hopper, and a master batch feeding amount adjustment unit that adjusts the feeding amount of the master batch fed into the hopper, and it is preferable that at least one of the feeding ratio of the recycled resin material and the new resin material and the feeding amount of the master batch is adjusted based on the color concentration information. This makes it possible to appropriately adjust the amount of at least one of the recycled resin material, new resin material, and master batch added based on the color density information, and to mold a molded product with a desired color density.

[0087] In the injection molding system of this embodiment, the color inspection unit calculates color unevenness information of the molded product, and the injection molding machine has a hopper for feeding the resin material and the master batch, a cylinder to which the resin material and the master batch fed from the hopper are sent, a heating unit for heating and plasticizing the resin material and the master batch in the cylinder, a screw that is inserted into the cylinder to knead the resin material and the master batch and has an adjustable rotational speed, and an injection unit that pushes out the kneaded product of the resin material and the master batch in the cylinder, and it is preferable that at least one of the plasticization temperature, the rotational speed of the screw, the kneading time of the resin material and the master batch by the screw, and the injection pressure in the injection unit is adjusted based on the color unevenness information. This makes it possible to adjust at least one of the plasticization temperature, the screw rotation speed, the residence time, and the injection pressure based on the color unevenness information, thereby making it possible to mold a molded product without color unevenness.

[0088] In the injection molding system of this aspect, it is preferable to further include a foreign matter detection unit that detects foreign matter contained in the molded article based on the spectral image. This allows for further inspection of whether or not molded products produced by the injection molding system contain foreign objects.

[0089] In the injection molding system of this aspect, it is preferable to further include a shape inspection unit that inspects the shape of the molded product based on the spectral image. This allows for additional inspection of molded parts produced in an injection molding system for shape anomalies. [Explanation of symbols]

[0090] 1,1A...injection molding system, 10,10A...color inspection device, 11...stage, 12...color reference body, 13...illumination section, 14...imaging section, 15...inspection processing section, 20...injection molding machine, 21...hopper, 22...resin input ratio adjustment section, 23...master batch input amount adjustment section, 24...cylinder, 25...heating section, 26...screw, 27...injection section, 28...molding mold, 29...injection control section, 151...memory section, 152...processor, 152A...spectral image acquisition section, 152B...range identification section, 152C...chromaticity calculation section, 152D...color inspection section, 152E...pass / fail judgment section, 152F...shape inspection section, 152G...rank judgment section, 241...nozzle, 291...reference molding control section, 292...concentration adjustment control section, 293...color unevenness adjustment control section, 294...molding machine side memory section.

Claims

1. A color inspection device for inspecting the color of a molded product obtained by injection molding a resin material, A spectral image acquisition unit that acquires spectral images of the molded product at a plurality of spectral wavelengths; a chromaticity calculation unit that calculates chromaticity information related to colors of a plurality of measurement points of the molded product from the spectral images for the plurality of spectral wavelengths; a color inspection unit that performs a color inspection of the molded product based on the chromaticity information of the plurality of measurement points; A color inspection device comprising:

2. a range specifying unit that specifies an image range of the molded product included in the spectroscopic image as an inspection range, the chromaticity calculation unit calculates the chromaticity information of each of the measurement points by using pixels included in the inspection range as the measurement points; the color inspection unit calculates an arithmetic average of the chromaticity information of each of the measurement points as average chromaticity information, and calculates color density information of each color based on the average chromaticity information. The color inspection device according to claim 1 .

3. The color inspection unit calculates a yellowness of the molded product as the color density information from the average chromaticity information. The color inspection device according to claim 2.

4. a range specifying unit that specifies an image range of the molded product included in the spectroscopic image as an inspection range, the chromaticity calculation unit calculates the chromaticity information of each of the measurement points by using pixels included in the inspection range as the measurement points; the color inspection unit calculates average chromaticity information, which is an arithmetic average of the chromaticity information of each of the measurement points, and σ, which is a standard deviation, and calculates, as color unevenness information, a color difference between the average chromaticity information and chromaticity information obtained by adding 3σ to the average chromaticity information, and a color difference between the average chromaticity information and chromaticity information obtained by subtracting 3σ from the average chromaticity information. The color inspection device according to claim 1 .

5. The molded product is further provided with a pass / fail determination unit that determines whether the molded product is a non-defective product based on a color inspection result by the color inspection unit. The color inspection device according to claim 1 .

6. The molding machine further includes a rank determining unit that ranks the quality of the molding based on a color inspection result by the color inspection unit. The color inspection device according to claim 1 .

7. A color inspection device according to claim 1 ; and an injection molding machine that forms the molded product by injection molding, The injection molding machine adjusts injection molding conditions based on the color inspection result of the color inspection unit.

1. An injection molding system comprising:

8. The color inspection unit calculates color density information of each color of the molded product, The injection molding machine has a hopper into which the recycled resin material, the new resin material, and the master batch are charged, a resin charge ratio adjustment unit that adjusts the charge ratio of the recycled resin material and the new resin material charged into the hopper, and a master batch charge amount adjustment unit that adjusts the charge amount of the master batch charged into the hopper, and adjusts at least one of the charge ratio of the recycled resin material and the new resin material and the charge amount of the master batch based on the color concentration information.

8. The injection molding system of claim 7.

9. The color inspection unit calculates color unevenness information of the molded product, the injection molding machine has a hopper for introducing the resin material and the master batch, a cylinder for receiving the resin material and the master batch introduced from the hopper, a heating section for heating and plasticizing the resin material and the master batch in the cylinder, a screw for kneading the resin material and the master batch by being inserted into the cylinder and for which the rotation speed is adjustable, and an injection section for extruding the kneaded product of the resin material and the master batch in the cylinder, and adjusts at least one of a plasticization temperature, a rotation speed of the screw, a kneading time of the resin material and the master batch by the screw, and an injection pressure in the injection section based on the color unevenness information; 8. The injection molding system of claim 7.

10. The method further includes the steps of: detecting a foreign object contained in the molded product based on the spectral image; 8. The injection molding system of claim 7.

11. Further comprising a shape inspection unit that inspects the shape of the molded product based on the spectral image.

8. The injection molding system of claim 7.

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