JPH07107499B2 - Continuous colorimeter - Google Patents

Description

Detailed Description of the Invention

[Industrial applications]

The present invention relates to a continuous color measuring device, and in particular, in a manufacturing process of a product having a color tone such as iron, non-ferrous, plastic, and paper, a continuous color measuring device suitable for online measurement for use in quality control of the product. Regarding color devices.

[Prior art]

Since the color tone of an object is one of the important factors that determine the quality of the product, accurate measurement of this is strongly demanded. Therefore, for example, a colored zinc iron plate manufactured by applying a colored paint on a steel plate (hereinafter, referred to as "color steel plate"),
In the process of manufacturing plastics or paper, visual inspection and off-line inspection by sampling measurement are performed in order to make the color tone of the product surface a target. In addition, recently, a so-called on-line inspection for continuously performing color measurement during the manufacturing is being performed. For this reason, various online colorimetric inspection devices that have fast response and are capable of non-contact colorimetry have been developed and are commercially available. For example, in the case of color measurement of a color steel plate, a pickled steel plate, a color tile, a copper foil, etc., the present inventors have conducted an experiment using a device similar to the above-mentioned online colorimetric inspection device (“Kawasaki Steel Technical Report, Vol. 18, No. 2, pages 24 to 30). The results of this experiment are used for quality control of various products. Further, for example, a parallel detection type spectrophotometer disclosed in Japanese Patent Laid-Open No. 53-52183 is used to perform on-line color measurement, or strict spectral color measurement is not performed, and a commercially available color sensor is used. The use of the above-described process color inspection device has also been performed. By the way, color measurement belongs to sensitivity measurement, and when color measurement is performed using a measuring instrument, numerical calculation is performed in accordance with the visibility of human eyes. For this reason, the result of the numerical calculation differs depending on the measuring system, the light source, or the equipment such as the detector used, so that an absolute measured value cannot be obtained. Therefore, it is general to perform product quality control by using a relative value such as a color difference value which is a difference between a target standard sample and a target product. For that purpose, the standard sample is measured in advance and the colorimetric value is stored, or the on-line measuring device moves regularly to approach the installation position of the standard sample plate, and regularly performs sampling measurement. Then, comparative measurement with the colorimetric value of the traveling measurement object has been performed. However, in the above-mentioned conventional example, when the surface color tone of the object to be measured changes depending on the temperature, for example, when the color tone differs between high temperature and normal temperature, such as some paints applied to the color steel sheet. However, since the temperature difference between the standard sample at room temperature and the object to be measured at high temperature during manufacture is large, there is a problem in that it is not possible to perform highly accurate color tone management. In particular, if the coloring process is a high temperature process, there will be no problem when measuring the color in the final process when the temperature of the product is near room temperature, but it is possible to measure quickly in the upstream process and perform quick feedback. At times, the product temperature is high, a temperature difference from the standard sample occurs, and the measurement error increases,
The conventional example has a problem that the feed back control cannot be used.

[Problems to be achieved by the invention]

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is a continuous color measurement device capable of performing highly accurate color tone management in a manufacturing line or the like even for an object to be measured having a large temperature dependency of color tone. To provide.

[Means for Solving the Problems]

The present invention, in a continuous colorimetric device for measuring surface color tone information of a continuously measured object, an optical system for irradiating the object to be measured with white light and spectroscopically measuring reflected light, and an output of the optical system. An arithmetic unit that receives a signal and performs certain signal processing to calculate the color tone information, a standard sample calibration device that includes a standard sample having a color tone that is a standard of the measured object, and a surface temperature of the measured object. And a temperature control device for receiving the detection signal of the temperature measurement device and controlling the temperature of the standard sample to be substantially the same as the surface temperature of the object to be measured, It has achieved its purpose.

[Action]

The present invention continuously irradiates an object to be measured with a white body, and when measuring a color tone using a remote colorimeter that spectrophotometrically measures reflected light,
When the same sample is irradiated for a long time, the surface temperature of the sample rises over time due to the strong irradiation light, and the colorimetric values change, and some color steel sheets are different from those at the time of manufacturing. This was done based on the knowledge that the color tone is different after the product is completed, making quality control difficult. The inventors examined the relationship between temperature and color difference value using a color steel sheet as an example, and found that the characteristics greatly differ depending on the paint, but with the three-color paint used, the results shown in FIG. 2 were obtained. It was In FIG. 2, the horizontal axis represents the temperature difference ΔT from room temperature (or room temperature), and the vertical axis represents the color difference value ΔE based on the colorimetric value at room temperature (or room temperature). A, B, and C are characteristic curves when red, green, and blue paints are used, respectively. FIG. 2 shows that the color difference value Δ increases as the temperature difference ΔT from room temperature increases.
It shows that E becomes large. For this reason, for example, when the color difference value ΔE is set to 0.5 or less as a target of color tone management, the temperature of the standard sample and the temperature of the measured object can be matched within a range of 2 to 3 ° C. in the red color steel plate. Will be needed. Therefore, if the surface color tone of the measured object changes depending on the temperature or the color tone differs between high temperature and low temperature, the measured value of the standard sample at room temperature is not used as It is necessary to correspond the conditions and use the measured value near the temperature of the measured object at the manufacturing stage as a reference. For that purpose, the temperature of the object to be measured is actually measured, and until it reaches a temperature close to the temperature (for example, within a range of 2 to 3 ° C.),
It is necessary to control the temperature of the standard sample, which makes it possible to obtain the target color tone when the product reaches normal temperature. That is, in FIG. 2, in the case of the red color steel plate, the color difference value ΔE is close to 4 when the temperature difference ΔT from the room temperature is 20 ° C., but the temperature difference ΔT from the room temperature is controlled by controlling the temperature of the standard sample. Is controlled to about ± 1 ° C., the color difference value ΔE becomes about 0.2, and the color tone management is significantly improved.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. This embodiment is constructed as shown in FIG.
Reference numeral 1 denotes an object to be measured, which is made of, for example, a strip-shaped color steel plate and is manufactured by continuously running in the direction of the thick arrow (down) in FIG. Reference numerals 2 and 2'incorporate, for example, a light source using a halogen lamp, a spectroscopic system using a diffraction grating or a prism, and a detector composed of, for example, a photodiode array, to disperse the spectrum of the reflected light from the measured object 1. It is an optical system for detecting. Reference numeral 3 has an analog circuit such as a preamplifier, a main amplifier, and a multiplexer, and a digital circuit such as a 16-bit microcomputer, and the output signal S ₀ of the optical system 2
It is an arithmetic unit that performs analog processing such as amplification and distribution and digital processing such as color difference calculation on S ₀ ′ (spectral signal in the visible range). An output device 4 is an LED display, a printer, a recorder, or the like, which receives the output signal S ₁ of the arithmetic unit 3 to display or record color information. 5 receives the output signal S ₂ of the arithmetic unit 3 and receives the optical system driver 12
The standard sample plate via the slide mechanism 11.
It is a calibration signal transmitter that moves the optical system 2 to the vicinity of 10. The slide mechanism 11 and the optical system drive unit 12 are, for example, guide rails, ball screws, pulse motors, encoders, etc., and according to the output signal of the calibration signal transmitter 5,
The optical system 2 is moved in a thick arrow (generally left-right direction). Reference numeral 6 is a temperature control device for operating the heating device 7, for example, in order to bring the temperature of the standard sample plate 10 close to the temperature of the object 1 to be measured (substantially the same temperature) by the temperature detection temperature from the side temperature device 13. . The side temperature device 13 is, for example, a contact-type temperature measurement sensor or a sensor that measures the temperature in the vicinity of the traveling plate. As the heating device 7 and the temperature control device 6, for example, a device using a coil and a thermostat is used. 8 receives the output signal S ₄ of the arithmetic unit 3, and when the value is, for example, a set value or more, activates the control device 9 of the line facility to achieve the target color tone, and the manufacturing condition (for example, In the case of a color steel plate, it is a control device that changes the amount of paint applied, the baking temperature, the drying temperature, etc.). The operation of the embodiment will be described below. A light beam emitted from the optics of the optical system 2 (for example, a white light source) is reflected by the object to be measured 1, and the spectrum of the reflected light is detected by the detector of the optical system 2 via the spectroscopic system. The detection signal (for example, a spectrum signal in the visible region) is sent to the arithmetic unit 3, where analog processing by an analog circuit and digital processing by a digital circuit (for example, color difference calculation) are performed to calculate color information. This color information signal (that is, the output signal S ₁ of the arithmetic unit 3) is sent to the output unit 4 for display and recording. On the other hand, the temperatures of the object to be measured 1 and the standard sample plate 10 are detected by the measuring devices 13 and 13 ', and the detected signals are the temperature control device 6
Sent to. The output of the temperature measuring device 13 is the measured object 1
It is also sent to the arithmetic unit 3 so as to output a calibration signal when the temperature fluctuates. Signal processing such as comparison calculation is performed in the temperature control device 6, and the operation of the heating device 7 is controlled based on the result. Therefore, the standard sample plate 10 is controlled by the heating device 7 so as to have a temperature close to (substantially the same as) the temperature of the object 1 to be measured. In this state, when the measured object 1 changes, or when the temperature of the measured object 1 changes by a certain value or more, or at fixed time intervals, a calibration signal is transmitted according to the output signal S ₂ of the arithmetic unit 3. The output of the instrument 5 is sent to the optical system drive unit 12, and the vicinity of the standard sample plate 10 (calibration position) is passed through the slide mechanism 11.
The optical system 2 is moved to. At this calibration position, the illumination light from the light source of the optical system 2 is reflected by the standard sample plate 10 and the reflected light (spectrum) output signal S ₀ ′ is sent to the arithmetic unit 3. After being subjected to analog processing and digital processing, the arithmetic unit 3 stores the color information at the temperature of the standard sample plate 10 at this time (during calibration) in the memory in the arithmetic unit 3. After this operation (calibration operation) is completed, the optical system 2 returns to the measurement position of the measured object 1 again, compares the color information of the measured object 1 with the color information of the standard sample plate 10 at the time of calibration, and calculates the color difference. Calculate the value (ΔE). This calculation result is the calculation device 3
Is sent to the control device 8 or the like as an output signal S ₄ of the above to control the color tone of the measured object 1. That is, when the output signal S ₄ of the arithmetic unit 3 which is the above arithmetic result becomes a value (color difference value) which is equal to or more than the preset value set in the controller 8 or the like, the controller 8 operates and the line equipment is operated. The control device 14 of is also activated. Therefore, for example, the coating amount of color steel sheet,
Manufacturing conditions such as the baking temperature and the drying temperature are changed so that the object 1 to be measured can finally achieve the target color tone. In the above-mentioned examples, the present invention was applied to the color measurement of the color steel sheet, but the application target of the present invention is not limited to this, and the color of plastic, paper, resin, etc. changes depending on the temperature. Obviously, it can be applied to other easy objects as well.

【The invention's effect】

As described above in detail, according to the present invention, even for a measured object having a large temperature dependency of color tone, it is possible to perform highly accurate color tone management in a production line including a coloring step, and a stable product is obtained. Quality can be achieved. In addition, since color measurement can be performed in the upstream process, it has an excellent effect that various measures can be easily taken, such as being used for rapid feedback control in the upstream process.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a continuous colorimetric apparatus according to the present invention, and FIG. 2 shows an example of a relationship between a temperature difference and a color difference value in a color steel plate for explaining the principle of the present invention. It is a diagram. 1 ... Object to be measured, 2 ... Optical system, 3 ... Computing device, 4 ... Output device, 5 ... Calibration signal transmitter, 6 ... Temperature control device, 7 ... Heating device, 8 ... Control Equipment, 9 …… Line equipment control equipment, 10 …… Standard sample plate, 11 …… Slide mechanism, 12 …… Optical system drive section, 13 …… Temperature measuring device.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kenichiro Nakamura, 5-13-12 Daisawa, Setagaya-ku, Tokyo (72) Masakazu Fujita 1-4-4, Minamisenzuka, Ota-ku, Tokyo Toei Electronics Industry Within the corporation (56) Reference JP 62-36543 (JP, A) Actual 60-54939 (JP, U) Actual 52-129285 (JP, U) Actual 63-141447 (JP, U)

Claims (1)

[Claims] 1. A continuous colorimetric apparatus for measuring surface color tone information of an object to be measured that is continuously running, comprising: an optical system that irradiates the object to be measured with white light and spectroscopically measures reflected light; An arithmetic device that receives the output signal and performs certain signal processing to calculate the color tone information, a standard sample calibration device that includes a standard sample having a color tone that is the standard of the measured object, and the surface of the measured object. A temperature measuring device for detecting the temperature; and a temperature control device for receiving the detection signal of the temperature measuring device and controlling the temperature of the standard sample to be substantially the same as the surface temperature of the object to be measured. A continuous color measuring device.