Inspection equipment

Abstract

To accurately measure the electrostatic capacitance of fruits and vegetables while transporting them.SOLUTION: An inspection device 1 includes: a pair of rollers 21a, 21b which are provided in a conveyance path of fruits and vegetables W to be conveyed in a single row and whose surface is composed of a conductive material; and an electrostatic capacitance measurement part which measures the electrostatic capacitance between the pair of rollers 21a, 21b when the fruits and vegetables W are conveyed between the pair of rollers 21a, 21b.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] The present invention relates to an inspection apparatus for inspecting fruits and vegetables. [[Background Art]]

[0002] Conventionally, fruit and vegetable collection and shipping facilities are provided with a sorting apparatus that sorts fruits and vegetables carried in by producers according to grade and class, and a boxing apparatus that boxes the sorted fruits and vegetables. The sorting apparatus includes a conveyor that conveys fruits and vegetables, an inspection apparatus that is provided on the conveyance path of fruits and vegetables and inspects the grade and class of fruits and vegetables, and a sorting apparatus that sorts fruits and vegetables by grade and class.

[0003] For example, the inspection apparatus included in the sorting apparatus described in Patent Document 1 includes speed detection means for detecting the conveyance speed of fruits and vegetables conveyed by the conveyor, a pair of measurement electrodes arranged on both sides of the conveyor, and a computer that determines the class of fruits and vegetables based on the conveyance speed detected by the speed detection means and the capacitance measured via the measurement electrodes. [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2015-202458 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] The technology described in the above patent document is a technology for determining the class of fruits and vegetables while conveying them based on the capacitance measured by a pair of measurement electrodes and the conveyance speed. However, in order not to obstruct the conveyance of fruits and vegetables, it is necessary to set the interval between the pair of measurement electrodes to be larger than the size of the fruits and vegetables. Nevertheless, as a result of providing a sufficient interval between the pair of measurement electrodes in this manner, the output level of the signal output from the measurement electrodes becomes minute in proportion to the length of the interval, making it difficult to distinguish between signals and noise, and it has been difficult to measure capacitance with high accuracy.

[0006] Therefore, the present invention aims to provide an inspection device that can measure the capacitance of fruits and vegetables with high precision while transporting them. [Means for solving the problem]

[0007] To achieve the above objective, the inspection apparatus of the present invention is characterized by comprising a pair of rollers provided in a transport path for single-row transported fruits and vegetables, the rollers having surfaces made of a conductive material, and a capacitance measuring unit that measures the capacitance between the pair of rollers when the fruits and vegetables are transported between the pair of rollers.

[0008] Furthermore, the pair of rollers is characterized by comprising an upstream roller positioned on the upstream side in the direction of transporting the produce, and a downstream roller positioned on the downstream side in the direction of transport.

[0009] Furthermore, the system is equipped with a sensor that detects the fruits and vegetables being transported between the pair of rollers, and the capacitance measuring unit measures the capacitance when the fruits and vegetables are detected by the sensor.

[0010] Furthermore, the system is characterized by comprising a weight measuring unit for measuring the weight of the fruits and vegetables on the pair of rollers. [Effects of the Invention]

[0011] According to the present invention, the capacitance of fruits and vegetables can be measured with high precision while the fruits and vegetables are being transported. [Brief explanation of the drawing]

[0012] [Figure 1] Side view of an inspection apparatus according to an embodiment of the present invention. [Figure 2] Plan view of the above inspection device [Figure 3] Front view of the above inspection device [Figure 4] Block diagram of the above inspection device [Figure 5] This is a modified example of the capacitance detection unit of the above-mentioned inspection device, (a) a side view of the modified example, and (b) a front view of the pair of rollers of the modified example. [Modes for carrying out the invention]

[0013] Hereinafter, an inspection apparatus according to an embodiment of the present invention will be described based on the drawings.

[0014] As shown in Figure 1, the inspection device 1 according to this embodiment is a device for inspecting fruits and vegetables W, and is installed in a sorting device within a fruit and vegetable collection and shipping facility, in a transport path that transports fruits and vegetables W in a single row. This transport path is formed by an upstream conveyor 2 and a downstream conveyor 3 arranged in series so that the transport direction is the same. In this embodiment, the upstream conveyor 2 and the downstream conveyor 3 are belt conveyors with belts wider than the fruits and vegetables W to be transported, but they are not limited to belt conveyors and may be roller conveyors or the like that which transport fruits and vegetables W in a single row. The inspection device 1 is positioned between such an upstream conveyor 2 and a downstream conveyor 3.

[0015] The inspection device 1 comprises a capacitance detection unit 20, a weight detection unit 30, and a computer 40 (Figure 4), with the capacitance detection unit 20 and the weight detection unit 30 being electrically connected to the computer 40.

[0016] The capacitance detection unit 20 is a unit for individually detecting the capacitance of the transported produce W, and is equipped with a pair of rollers 21a and 21b. The pair of rollers 21a and 21b function as electrodes that supply electrical signals to the produce W for capacitance detection, and as shown in Figure 2, they are equipped with cylindrical main bodies 211a and 211b and rotating shafts 212a and 212b that rotate the main bodies 211a and 211b. The main bodies 211a and 211b extend in a horizontal direction perpendicular to the transport direction of the produce W, and are formed to be slightly longer than the belt width of the conveyors 2 and 3. The rotating shafts 212a and 212b extend in a horizontal direction perpendicular to the transport direction, and are inserted through the center of the main bodies 211a and 211b so that both ends protrude from the main bodies 211a and 211b.

[0017] As shown in Figure 1, the pair of rollers 21a and 21b are arranged in parallel, with an upstream roller 21a positioned upstream in the direction of transporting the produce W, and a downstream roller 21b positioned downstream in the direction of transporting the produce W. In this embodiment, the upstream roller 21a is positioned slightly lower than the upstream conveyor 2, and the downstream roller 21b is positioned slightly lower than the upstream roller 21a. The downstream conveyor 3 is positioned slightly lower than the downstream roller 21b. That is, the upstream conveyor 2, the upstream roller 21a, the downstream roller 21b, and the downstream conveyor 3 are arranged in this order, with their heights gradually decreasing. The rotation axes 212a and 212b of each roller 21a and 21b are rotated by a motor via gears (not shown). As the rotation axes 212a and 212b rotate, the produce W transported from the upstream conveyor 2 moves through the upstream roller 21a and the downstream roller 21b to the downstream conveyor 3.

[0018] Here, the surfaces of the respective rollers 21a and 21b are formed of a conductive material. In the present embodiment, the entire surfaces of main body portions 211a and 211b are covered with a conductive sheet, but the main body portions 211a and 211b themselves may be formed of a conductive material such as metal. As shown in FIGS. 2 and 3, the capacitance detection unit 20 includes small metal rollers 22a and 22b that abut against the surfaces of the respective rollers 21a and 21b. The metal roller 22a disposed in front of the upstream roller 21a is pivotally supported by a metal support arm 23a so as to rotate in accordance with the rotation of the upstream roller 21a, and is electrically connected to the ground of a measurement circuit 24 (FIG. 4) via the support arm 23a. The metal roller 22b disposed behind the downstream roller 21b is pivotally supported by a metal support arm 23b so as to rotate in accordance with the rotation of the downstream roller 21b, and is wired and connected to the input of the measurement circuit 24 (FIG. 4) via the support arm 23b.

[0019] As shown in FIG. 4, the measurement circuit 24 is a circuit that measures the capacitance generated between the upstream roller 21a and the downstream roller 21b, and the electrical output thereof is input to an analog-to-digital conversion circuit 25 (hereinafter referred to as ADC 25). The ADC 25 converts the electrical signal input from the measurement circuit 24 into a digital signal and inputs the digital signal to a computer 40. The computer 40 measures the capacitance of the fruit / vegetable W based on the digital signal input from the ADC 25. Here, the capacitance of the fruit / vegetable W is calculated by obtaining the difference between the capacitance when the fruit / vegetable W is present between the pair of rollers 21a and 21b and the capacitance when the fruit / vegetable W is not present therebetween. As described above, the measurement circuit 24, the ADC 25, and the computer 40 function as a capacitance measurement unit that measures the capacitance of the fruit / vegetable W.

[0020] As shown in Figures 2 and 3, the pair of rollers 21a and 21b are each pivotally supported by the support member 26 of the capacitance detection unit 20. The support member 26 of the present embodiment is a metal fitting formed in a U-shape, and the rotating shafts 212a and 212b of the rollers 21a and 21b respectively are bridged at both ends of the metal fitting. The support member 26 is provided on the horizontal plate 27 of the capacitance detection unit 20. The horizontal plate 27 is a metal plate extending in the horizontal direction, and the support member 26 is joined to the central portion thereof.

[0021] The capacitance detection unit 20 includes a photoelectric sensor 10. The photoelectric sensor 10 is a sensor that detects fruits and vegetables W conveyed between the pair of rollers 21a and 21b. In the present embodiment, it comprises a light emitting unit 10a that emits infrared rays and a light receiving unit 10b that receives the infrared rays. The light emitting unit 10a and the light receiving unit 10b are arranged opposite to each other on respective sides (the right side and the left side) of the pair of rollers 21a and 21b. The infrared rays emitted from the light emitting unit 10a toward the light receiving unit 10b are blocked by the fruit or vegetable W that has entered between the pair of rollers 21a and 21b. As shown in Figure 4, the output of the light receiving unit 10b is connected to the computer 40. The light receiving unit 10b outputs an on signal when receiving infrared rays from the light emitting unit 10a, and outputs an off signal when the infrared rays are blocked by the fruit or vegetable W. The computer 40 determines the presence or absence of the fruit or vegetable W between the pair of rollers 21a and 21b by polling the input from the light receiving unit 10b.

[0022] As shown in Figures 1 and 3, a weight detection unit 30 is provided below the capacitance detection unit 20. The weight detection unit 30 is a unit that detects the weight of the transported produce W and is equipped with a load cell 31. The load cell 31 functions as a weight detection unit that detects the weight of the produce W and is positioned on a horizontally extending base plate 32. The load cell 31 outputs an electrical signal of the strain caused by the weight of the produce W passing through a pair of rollers 21a and 21b. As shown in Figure 4, the electrical signal output from the load cell 31 is input to an ADC 33, converted into a digital signal by the ADC 33, and input to a computer 40. The computer 40 measures the weight of the produce W based on the digital signal input from the ADC 33. The weight of the produce W is calculated by determining the weight difference when the produce W is on the pair of rollers 21a and 21b and when it is not. In this way, the ADC 33 and the computer 40 function as a weight measuring unit that measures the weight of the produce W.

[0023] As described above, the computer 40 is electrically connected to the photoelectric sensor 10 and is also connected to the capacitance measurement circuit 24 and load cell 31 via ADCs 25 and 33. The computer 40 includes a memory (not shown) in which a control program is pre-stored and a CPU (not shown). The CPU executes the control program to measure the capacitance and weight of the produce being transported between the pair of rollers 21a and 21b.

[0024] Specifically, the CPU of the computer 40 polls the input signal from the photoelectric sensor 10 and determines the presence or absence of produce W between the pair of rollers 21a and 21b based on the input signal. Specifically, if the input signal is an ON signal, it is determined that there is no produce W between the pair of rollers 21a and 21b, and if the input signal is an OFF signal, it is determined that the produce W is straddling the pair of rollers 21a and 21b.

[0025] If the CPU of computer 40 determines, based on the input signal from the photoelectric sensor 10, that there are no fruits or vegetables W between the pair of rollers 21a and 21b, it obtains the output of the ADC 25 connected to the measurement circuit 24 to measure the capacitance (reference capacitance) when there are no fruits or vegetables W. On the other hand, if the CPU of computer 40 determines, based on the input signal from the photoelectric sensor 10, that there are fruits or vegetables W spanning across the pair of rollers 21a and 21b, it obtains the output of the ADC 25 to measure the capacitance (variable capacitance) when there are fruits or vegetables W. The CPU then calculates the difference between the variable capacitance and the reference capacitance to determine the capacitance of the fruits or vegetables W.

[0026] Furthermore, if the CPU of the computer 40 determines, based on the input signal from the photoelectric sensor 10, that there are no fruits or vegetables W between the pair of rollers 21a and 21b, it obtains the output of the ADC 33 connected to the load cell 31 to measure the weight (reference weight) when there are no fruits or vegetables W. On the other hand, if the CPU of the computer 40 determines, based on the input signal from the photoelectric sensor 10, that there are fruits or vegetables W between the pair of rollers 21a and 21b, it obtains the output of the ADC 33 to measure the weight (variable weight) when there are fruits or vegetables W. The CPU then calculates the difference between the variable weight and the reference weight to determine the weight of the fruits or vegetables W.

[0027] In this embodiment, the density of the produce W is calculated based on the measured capacitance and weight of the produce W, and the internal quality of the produce W is determined by the calculated density value. Specifically, the volume is calculated from the capacitance based on a predetermined calibration curve that shows the relationship between capacitance and volume, and the density is calculated by multiplying the measured weight by the reciprocal of the calculated volume.

[0028] Here, if the inspection device 1 of this embodiment is used, for example, as a device to inspect the internal quality of potatoes, if the calculated density is below a certain value, it will be judged as a substandard product, meaning that there are cavities inside or that the starch content is low. Also, if it is used, for example, as a device to inspect the internal quality of tomatoes, if the calculated density is below a certain value, it will be judged as a grade, meaning that there are cavities inside. Also, if it is used, for example, as a device to inspect the internal quality of mandarins, if the calculated density is below a certain value, it will be judged as a substandard product, meaning that the peel is loose. Also, if it is used, for example, as a device to inspect the internal quality of onions, if the calculated density is above a certain value, it will be judged as a substandard product, meaning that there are problems with the internal quality.

[0029] According to the inspection device 1 of this embodiment, the surfaces of the pair of rollers 21a and 21b function as measuring electrodes for measuring capacitance. Therefore, by measuring the capacitance when the transported produce W comes into contact with the surfaces of the pair of rollers 21a and 21b, the capacitance of the produce W can be measured with high accuracy.

[0030] Although embodiments of the present invention have been described above, the embodiments are not limited to those described above, and may also be modified embodiments as described below.

[0031] [Example 1] In the above embodiment, the entire surface of the main bodies 211a and 211b of the pair of rollers 21a and 21b is formed of a conductive material, but it is also acceptable for only the portion over which the produce W passes to be formed of a conductive material.

[0032] [Differentiation 2] In the above embodiment, the pair of rollers 21a and 21b rotate at the same rotational speed, but the rotational speeds of the pair of rollers 21a and 22b may be different. For example, the rotational speed of the upstream roller 21a may be set to be slower than the rotational speed of the downstream roller 21b. By setting the rotational speeds to be different in this way, it is possible to prevent the produce W from continuing to rotate on the pair of rollers 21a and 21b.

[0033] [Difference 3] In the above embodiment, the arrival of fresh produce W is detected by photoelectric sensors 10 positioned opposite each other on the sides of the pair of rollers 21a and 21b. However, the photoelectric sensors 10 may also be positioned opposite each other above and below the pair of rollers 21a and 21b.

[0034] [Differentiation Example 4] In the above embodiment, a photoelectric sensor 10 is used to detect the produce W, but the produce W may also be detected using cameras provided on a pair of rollers 21a and 21b. In the embodiment using cameras, the cameras are provided to communicate with a computer 40, and the captured images generated by the cameras are input to the computer 40. When the computer 40 acquires the captured images from the cameras, it can analyze the captured images to detect the produce being transported on the pair of rollers 21a and 21b.

[0035] [Difference 5] The load cell 31 is not limited to one; there may be multiple load cells. This modified inspection device includes an averaging circuit that averages the output signals of multiple load cells, and the output signal of this circuit is input to the ADC. As a result, the weight of the produce W entering the inspection device 1 is distributed among the load cells, making it possible to reduce the measurement range of each load cell. This allows for the use of load cells with finer resolution, thus enabling more precise measurement of the weight of the produce.

[0036] [Modification 6] In the above embodiment, the rollers 21a and 21b are arranged front and back (upstream and downstream) in the direction of transporting the produce W. However, as shown in Figure 5, the pair of rollers 21c and 21d may be arranged left and right (both sides of the transport path) with respect to the direction of transporting the produce W. In this modified embodiment, each of the pair of rollers 21c and 21d is equipped with a frustoconical body portion 211c and 211d, and the planes (small circular surfaces) of the body portions are arranged to face each other. Each of the pair of rollers 21c and 21d is attached to a horizontal rotation shaft 212 perpendicular to the transport direction, and rotates in conjunction with the rotation of the rotation shaft 212. When produce W is transported from the upstream conveyor 2 to such a pair of rollers 21c and 21d, the produce W is positioned across the inclined surfaces of each of the rollers 21c and 21d, and the produce W is transported toward the downstream conveyor 3 by the rotation of the pair of rollers 21c and 21d. Here, the surfaces of each of the pair of rollers 21c and 21d are formed of a conductive material, as in the embodiment, and small rollers 22c and 22d that contact the sides 213c and 213d of the pair of rollers 21c and 21d are wired to the terminals of the measurement circuit 24. As in the embodiment described above, the pair of rollers 21c and 21d are supported by the weight detection unit 30. [Explanation of Symbols]

[0037] 1. Inspection device 2 Upstream conveyor 3 Downstream conveyor 10 Photoelectric Sensor 20 Capacitance detection unit 21a Upstream roller 22b Downstream roller W Fruits and Vegetables 30 Weight detection units

Claims

1. A pair of rollers are provided in the transport path for single-row transported fruits and vegetables, which transport the fruits and vegetables and whose contact surfaces are made of a conductive material, A capacitance measuring unit measures the capacitance between the pair of rollers when the produce is being transported between the pair of rollers, while the produce is in contact with the pair of rollers. Equipped with, The pair of rollers are An upstream roller positioned on the upstream side in the direction of transporting the produce, A downstream roller positioned on the downstream side in the aforementioned conveying direction, An inspection device equipped with the following features.

2. The system includes a sensor that detects the fruits and vegetables being transported between the pair of rollers, The inspection apparatus according to claim 1, characterized in that the capacitance measuring unit measures the capacitance when the fruit or vegetable is detected by the sensor.

3. The inspection apparatus according to claim 1 or claim 2, further comprising a weight measuring unit for measuring the weight of the fruits and vegetables on the pair of rollers.

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