JP2005066434A - Apparatus for sorting foreign matter in tea leaf - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sorting apparatus which can sort and remove foreign matter in tea leaves, which has similar color as that of a tea leaf. <P>SOLUTION: Foreign matter-containing tea leaves put on a detection section (1) is irradiated with light, optical response from the foreign matter-containing tea leaves is detected, and on the basis of a detection signal, a removing device is operated to sort and remove the foreign matter in the tea leaves. In this foreign matter sorting apparatus, the foreign matter-containing tea leaves and a background (3) adjusted so as to give an optical response equal to that of the tea leaves are irradiated with light in the wavelength region of 300 nm to 500 nm, the intensity of reflected light and intensity of fluorescence emitted from the foreign matter-containing tea leaves are separately detected, and on the basis of the detected reflection light intensity and the fluorescence intensity, the foreign matter is sorted and removed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus for sorting foreign substances in tea leaves.

  Conventionally, as a method for sorting out foreign matters in tea leaves, after removing foreign matters due to a difference in specific gravity or magnetic electrostatic difference, a method of removing foreign matters based on a difference in color using a so-called color sorter has been adopted ( For example, see Patent Documents 1 and 2).

However, the color sorter is difficult to detect when the color of the foreign matter in the tea leaf is similar to the color of the tea leaf, and it is difficult to sort out such a foreign matter.
Moreover, although the apparatus which classify | selects the foreign material in polished rice by the difference in a fluorescent reaction is known (for example, refer patent document 3), the processed tea leaf does not show a fluorescent reaction like polished rice, and this apparatus uses it in the tea leaf. The foreign material could not be sorted out.
JP 2002-35701 A JP 2002-316100 A Japanese Patent Laid-Open No. 10-7672

  The problem to be solved and used by the present invention is that it is difficult to detect the foreign matter in the tea leaf when the color of the foreign matter is similar to the color of the tea leaf, and it is difficult to sort out such a foreign matter. There is a point.

  The inventor of the present invention investigates the response by irradiating the tea leaf and the foreign matter with various lights in order to be able to select the foreign matter similar to the color of the tea leaf mixed in the tea leaf from the tea leaf. did. As a result, they discovered that the fluorescence reaction to light of a specific wavelength shows a clearly different reaction.

  1 and 2 are graphs showing such a difference in fluorescence reaction. FIG. 1 is a graph showing measurement results of fluorescence reaction characteristics when tea leaves are irradiated with near ultraviolet rays having a wavelength range centered on 365 nm. FIG. 2 is a graph showing measurement results of fluorescence reaction characteristics when the tea leaves are irradiated with blue light having a wavelength range centered at 470 nm. As can be seen from these graphs, tea leaves exhibit a strong fluorescence reaction in the wavelength range of 650 nm to 850 nm in any case when irradiated with light in the wavelength range as described above. On the other hand, a foreign substance having a color different from that of tea leaves and a foreign substance having a color similar to the color of tea leaves do not show such a specific fluorescence reaction (see FIG. 3). This is considered to be a reaction derived from chlorophyll contained in tea leaves. From such experimental results, the inventor of the present invention irradiates tea leaves containing foreign matters with light of 300 nm to 500 nm and measures the difference in fluorescence emission intensity in the wavelength range of 650 nm to 850 nm. It was recognized that foreign matter having a color similar to that of tea leaves can be distinguished and such foreign matter can be selectively removed.

  Therefore, the present invention irradiates the tea leaves and the foreign matters mixed therein with light having a wavelength of 300 nm to 500 nm, and detects the foreign matters due to the difference in the fluorescence reaction between the tea leaves and the foreign matters having similar colors. And removing.

  In the foreign matter sorting apparatus of the present invention, foreign matter having a color similar to tea leaves irradiates light with a wavelength of 300 to 500 nm showing a fluorescence reaction that is clearly different from that of tea leaves. There is an advantage that a foreign substance having a color similar to the tea leaf can be effectively detected and selected and removed.

  FIG. 4 is a configuration diagram showing the configuration of the detection unit of the sorting apparatus of the present invention. Tea leaves that may contain foreign substances are supplied so as to pass through the detection portion 1 by a chute or a belt conveyor, and those determined to be foreign substances are removed by a general exclusion device such as an air gun. That is, the configuration for supplying tea leaves and the like by the chute and the configuration for removing the foreign matter by the air gun upon receiving the foreign matter detection signal are the same as those of the conventional device, and are therefore omitted to simplify and clarify the description. Yes. The detection unit includes the illumination device 2, the background 3, the first filter 4, the second filter 4 ′, the first detection element 5, the second detection element 5 ′, and the determination circuit 6. The illuminating device 2 emits light having an excitation wavelength of 300 nm to 500 nm and does not emit light having other wavelengths. Fluorescent lamps, LEDs, halogen bulbs with filters, and the like can be used as the lighting device 2. As for the background 3, the brightness is set so that the signal level from the background detected by the first detection element 5 and the second detection element 5 ′ is close to the signal level from tea leaves, as in the conventional color sorter. Is done. The illumination device irradiates the tea leaves and the background 3 supplied to the detection portion 1. The detection mechanism includes a lens 7, a dichroic mirror or half mirror 8, a first filter 4, a second filter 4 ', a first detection element 5 such as a photodiode or a CCD, and a second detection element 5'. The light from the tea leaves and the background is collected by the lens 7, dispersed by the dichroic mirror 8, and sent to the first filter 4 and the second filter 4 ', respectively. The first filter 4 transmits a wavelength of 300 nm to 500 nm to the first detection element 5. Therefore, the first detection element 5 detects a color difference (brightness difference) from tea leaves and foreign matter at 300 nm to 500 nm, and detects a foreign matter having a clear color difference with respect to tea leaves as in the conventional color sorter. To do. On the other hand, the second filter 4 ′ transmits a wavelength of 650 nm to 850 nm and sends it to the second detection element 5 ′. Accordingly, the second detection element 5 ′ detects the intensity of fluorescence from 650 nm to 850 nm emitted from tea leaves or the like, and detects the foreign substances based on the difference in fluorescence emission intensity between the tea leaves and the foreign substances. The determination circuit 6 processes the signal from each detection element, and determines whether it is a tea leaf or a foreign substance that passes through the detection portion 1. That is, the signal from the first detection element 5 is supplied to the first comparator 9 and compared with the reference level 1, and when a detection signal outside the reference level is generated, it is determined that the signal is a foreign substance and is excluded. Generate a signal. The reference level 1 is set so that the signal level of the light intensity generated by the tea leaves falls within that range. On the other hand, the signal from the second detection element 5 ′ is supplied to the second comparator 9 ′ and compared with the reference level 2, and when a detection signal outside the reference level is generated, it is determined as a foreign substance. Generate an exclusion signal. The reference level 2 is set so that the signal level of the fluorescence intensity generated by the tea leaves falls within that range. When an exclusion signal is generated by any of the comparators, the exclusion device is activated to remove foreign matter. In FIG. 4, the levels of the signals of the first detection element 5 and the signal of the second detection element 5 ′ are merely compared with the reference levels for the respective signals. It is also possible to determine by calculating the signal of the second detection element 5 ′.

  FIG. 5 shows an example of the detection signal. a represents a detection signal of reflected light intensity of 300 nm to 500 nm, and b represents a detection signal of fluorescence intensity at 650 nm to 850 nm. In the figure, signal 1 is detected only by background, signal 2 is detected by tea leaf in 2, signal by foreign matter having higher brightness than tea leaf is detected in 3, signal in 4 A signal due to a foreign matter having a lightness lower than that of the tea leaf is detected. In 5, a signal due to a foreign matter having a color similar to that of the tea leaf is detected.

Industrial application fields

As described above, according to the present invention, it is possible to reliably sort out foreign substances having a color similar to that of tea leaves, which has been difficult in the past.
Although the present invention relates to sorting of tea leaves, it goes without saying that it can also be applied to sorting objects having similar characteristics other than tea leaves.

It is the graph which showed the measurement result of the fluorescence reaction characteristic when near ultraviolet rays which have a wavelength range centering on 365 nm are irradiated to tea leaves. It is the graph which showed the measurement result of the fluorescence reaction characteristic when irradiating the blue light which has a wavelength range centering on 470 nm to a tea leaf. It is the graph which showed the measurement result of the fluorescence reaction characteristic when irradiating the blue light which has the wavelength range centering on 470 nm to the foreign material of the color different from a tea leaf, and the foreign material similar to a tea leaf. It is the block diagram which showed the structure of the detection part of the screening device of this invention. It is a graph which shows the example of the detection signal by a detection element.

Explanation of symbols

1 detection part, 2 illumination device, 3 background,
4 first filter, 4 'second filter,
5 first detection element, 5 ′ second detection element,
6 judgment circuit, 7 lens, 8 dichroic mirror,
9 First comparator, 9 'Second comparator

Claims (3)

Irradiate tea leaves containing foreign substances to be administered to the detection part, detect the optical response from the tea leaves containing the foreign substances, and operate the exclusion device based on the signal from the detected optical response to select the foreign substances A foreign matter sorting device adapted to sort and remove foreign matter in tea leaves to be removed,
Irradiating a light beam having a wavelength range of 300 nm to 500 nm to a tea leaf containing foreign matter and a background adjusted to have an optical response equivalent to that of tea leaf, detecting the intensity of fluorescence emitted from the tea leaf containing the foreign matter, A foreign matter sorting apparatus adapted to sort and remove foreign matter based on the detected fluorescence intensity. The foreign matter sorting apparatus according to claim 1,
A foreign matter sorting apparatus which detects fluorescence intensity in a wavelength range of 650 nm to 850 nm emitted from tea leaves containing the foreign matter, and sorts and removes the foreign matter based on the detected fluorescence intensity. Irradiate tea leaves containing foreign substances administered to the detection part, detect the optical response from the tea leaves containing the foreign substances, and operate the exclusion device based on the signal from the detected optical response to select and remove the foreign substances A foreign matter sorting device adapted to sort and remove foreign matter in tea leaves,
An irradiation device for irradiating a light beam having a wavelength range of 300 nm to 500 nm on a tea leaf containing a foreign substance and a background adjusted to have an optical response equivalent to that of the tea leaf;
A first detection device that detects the intensity of light in a wavelength region of 300 nm to 500 nm reflected from a tea leaf containing the foreign substance, and determines the foreign substance by comparing the intensity signal of the detected light with a reference signal;
A second detection device that detects the intensity of fluorescence in a wavelength region of 650 nm to 850 nm generated from tea leaves containing the foreign substance, and determines the foreign substance by comparing the detected fluorescence intensity with a reference signal;
A foreign matter sorting apparatus including: a rejection device that is operated when the first detection device or the second detection device determines that the foreign matter is a foreign matter.

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