Foreign particle removal system and foreign particle removal method

Abstract

This invention provides a foreign matter particle removal system and method that can detect magnetic foreign matter particles contained in an object being inspected as it is being transported in the transport direction, and perform removal or marking of these magnetic foreign matter particles. [Solution] The foreign particle removal system 10,110,111 includes a first magnetic sensor 1 located at a first transport position HH1 and outputting a first sensor signal S1(t), a second magnetic sensor 2 located at a second transport position HH2 and outputting a second sensor signal S2(t), a foreign object detection unit 40,140 that detects a first timing t1 and a second timing t2 of the passage of magnetic foreign particles through the first transport position and the second transport position from the first and second sensor signals, a removal unit processing unit 50,55 located at a third transport position HH3 that removes the removal unit EP containing the detected magnetic foreign particles, or applies a removal mark MK to the removal unit EP of the inspected object IM, and an operation timing acquisition unit 60 that obtains an operation timing t3 to activate the removal unit processing unit from the first and second timings.

Description

Technical Field

[0001] The present invention relates to a foreign particle removal system and a foreign particle removal method for detecting magnetic foreign particles contained in an inspection object transported in a transport direction and removing the same.

Background Art

[0002] Patent Document 1 discloses a foreign matter detection unit that detects metal foreign matter mixed in a slurry flowing in a flow path, and a reject valve provided on the downstream side of the foreign matter detection unit to discriminate whether the slurry flows through a normal flow path or a discharge flow path. An electrode plate manufacturing apparatus is provided.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in order to predict the timing from when a foreign object is detected by the foreign object detection unit until the foreign object transported together with a slurry or the like reaches a removal device such as a reject valve, in addition to obtaining in advance the distance from the foreign object detection unit to the removal device, it is necessary to obtain a transport speed such as the flow rate of the slurry. As a method for obtaining this transport speed, methods such as measuring the transport speed of a transport belt that transports a transport object with an encoder or the like, or measuring the flow rate of a transport object flowing in a pipe with a flow meter and calculating it can be considered.

[0005] However, in the case of using a mechanical encoder or the like, temporal changes such as wear of bearings and rollers are likely to occur. In addition, non-contact speed meters using lasers or the like are expensive, and the measurement accuracy may vary depending on changes in the surface state of the measurement site.

[0006] The present invention has been made in view of the current situation and provides a foreign matter particle removal system and a foreign matter particle removal method that can detect magnetic foreign matter particles contained in an object to be inspected as it is transported in the transport direction and remove or mark these magnetic foreign matter particles. [Means for solving the problem]

[0007] (1) One aspect of the present invention for solving the above problems is a foreign matter particle removal system for removing magnetic foreign matter particles contained in an object to be inspected that is transported from the upstream side to the downstream side in the transport direction, comprising: a first magnetic sensor disposed at a first transport position in the transport direction and outputting a first sensor signal indicating whether or not the magnetic foreign matter particles have passed through the first transport position; a second magnetic sensor disposed at a second transport position downstream of the first transport position in the transport direction and outputting a second sensor signal indicating whether or not the magnetic foreign matter particles have passed through the second transport position; and from the first sensor signal and the second sensor signal, determining whether or not the magnetic foreign matter particles have passed through the first transport position and the first The foreign matter particle removal system comprises: a foreign matter detection unit that detects timing and detects whether or not the magnetic foreign matter particles have passed through the second transport position and a second timing when the magnetic foreign matter particles have passed through the second transport position; a removal unit processing unit located at a third transport position downstream of the second transport position, which removes the removal unit containing the magnetic foreign matter particles detected by the foreign matter detection unit from the object to be inspected, or applies a removal mark indicating the location of the removal unit to the removal unit of the object to be inspected or to a marked area determined from the location of the removal unit; and an operation timing acquisition unit that obtains an operation timing to operate the removal unit processing unit from the first timing and the second timing.

[0008] In this foreign particle removal system, the presence or absence of magnetic foreign particles passing through the first and second transport positions, as well as the first timing when the magnetic foreign particles pass through the first magnetic sensor and the second timing when they pass through the second magnetic sensor, are detected from the first and second sensor signals. Therefore, the operating timing acquisition unit can use these to easily obtain a predicted arrival timing when the part of the inspected object being transported reaches the removal section. Furthermore, the detected first and second timings can be used not only to obtain the transport speed of the object being inspected, but also to calibrate the transport speed obtained from separately installed transport speed detection means (flow meter, conveyor belt speed meter, encoder, etc.).

[0009] The objects to be transported include slurries such as active material paste, liquids such as electrolytes, powders and granules such as active material particles, aggregates of clay-like or solid pellets, strip-shaped films such as electrode plates and separators, individual clay-like or solid pellets, and individual components, all of which are transported inside pipes or on conveyors.

[0010] Furthermore, the removal processing unit includes a removal unit that removes the part of the inspected object containing magnetic foreign particles detected by the foreign object detection unit, as well as a marking unit that places a removal mark on the part of the inspected object to be removed or on a marking area determined from the location of the part to be removed. The part of the inspected object to be removed, on which the removal mark has been placed or on the marking area, is later removed from the inspected object by cutting or other means.

[0011] (2) The foreign matter particle removal system described in (1) further comprises a 1-2 difference acquisition unit that acquires a 1-2 difference signal which is the difference between the first sensor signal and the second sensor signal, and the foreign matter detection unit detects whether or not the magnetic foreign matter particles have passed through the first transport position and the first timing, and whether or not the magnetic foreign matter particles have passed through the second transport position and the second timing, from the 1-2 difference signal obtained from the first sensor signal and the second sensor signal.

[0012] In addition, it is preferable that the foreign matter particle removal system described in (1) or (2) is such that the object to be inspected is transported inside the piping, and the first magnetic sensor and the second magnetic sensor are located at the first circumferential position in the circumferential direction of the piping.

[0013] (3) Furthermore, a foreign particle removal system according to (1) or (2), comprising: a third magnetic sensor positioned at the first transport position facing the first magnetic sensor via the object to be inspected, and outputting a third sensor signal indicating the presence or absence of magnetic foreign particles contained in the object to be transported; a fourth magnetic sensor positioned at the second transport position facing the second magnetic sensor via the object to be inspected, and outputting a fourth sensor signal indicating the presence or absence of magnetic foreign particles contained in the object to be transported; and the difference between the first sensor signal and the third sensor signal The foreign object detection unit further comprises a 1-3 difference signal acquisition unit that acquires a 1-3 difference signal, and a 2-4 difference signal acquisition unit that acquires a 2-4 difference signal, which is the difference between the second sensor signal and the fourth sensor signal. The foreign object detection unit is a foreign object particle removal system that detects, from the 1-3 difference signal and the 2-4 difference signal obtained from the first to fourth sensor signals, whether or not the magnetic foreign object particles have passed through the first transport position and the first timing, and whether or not the magnetic foreign object particles have passed through the second transport position and the second timing.

[0014] (4) A foreign matter particle removal system as described in (3), further comprising a second-order difference signal acquisition unit that acquires a second-order difference signal which is the difference between the 1-3 difference signal and the second sensor signal, wherein the foreign matter detection unit detects from the second-order difference signal whether or not the magnetic foreign matter particles have passed through the first transport position and the first timing, and whether or not the magnetic foreign matter particles have passed through the second transport position and the second timing.

[0015] Furthermore, it is preferable to have a foreign particle removal system as described in (3) or (4), wherein the object to be inspected is transported inside a pipe, the first magnetic sensor and the second magnetic sensor are located at a first circumferential position in the circumferential direction of the pipe, and the third magnetic sensor and the fourth magnetic sensor are located at a second circumferential position on the opposite side of the circumferential direction from the first circumferential position.

[0016] (5) A foreign particle removal system according to any one of (1) to (4), wherein the part to be removed processing unit is a removal unit that removes the part to be removed from the object to be inspected, and further comprises a confirmation magnetic sensor located downstream of the removal unit and which outputs a confirmation sensor signal indicating whether or not the magnetic foreign particles have passed through the fourth transport position for the object to be inspected from which the part to be removed has been removed, and a confirmation unit that detects whether or not the magnetic foreign particles have passed through the fourth transport position from the confirmation sensor signal.

[0017] (6) A foreign matter particle removal system according to any one of (1) to (5) is further provided, which comprises a magnetization unit that, at a fifth transport position upstream of the first transport position in the transport direction, applies a magnetic field to the object to be inspected that is perpendicular to the transport direction and directed in a first direction toward the object to be inspected toward the first magnetic sensor, thereby magnetizing metallic foreign matter particles contained in the object to be inspected and converting them into magnetic foreign matter particles.

[0018] (7) Another aspect of the present invention for solving the above problems is a method for removing magnetic foreign particles contained in an object to be inspected that is transported from the upstream side to the downstream side in the transport direction, comprising: a first magnetic sensor positioned at a first transport position in the transport direction and outputting a first sensor signal indicating whether or not the magnetic foreign particles have passed through the first transport position; and a second magnetic sensor positioned at a second transport position downstream of the first transport position in the transport direction and outputting a second sensor signal indicating whether or not the magnetic foreign particles have passed through the second transport position, wherein the first sensor signal and the second sensor signal are acquired; and from the acquired first sensor signal and the second sensor signal, the presence or absence of the magnetic foreign particles passing through the first transport position and the magnetic foreign particles The foreign particle removal method comprises: a foreign object detection step of detecting a first timing when foreign particles have passed the first transport position, and detecting whether or not the magnetic foreign particles have passed through the second transport position and a second timing when the magnetic foreign particles have passed the second transport position; a processing unit operation step of activating a removal unit located at a third transport position downstream of the second transport position to remove the removal unit containing the magnetic foreign particles detected by the foreign object detection unit from the object to be inspected, or to apply a removal mark indicating the location of the removal unit to the removal unit or to a marked area determined from the location of the removal unit to be inspected; and an operation timing acquisition step of obtaining an operation timing to activate the removal unit processing unit from the first timing and the second timing.

[0019] In this foreign particle removal method, in the foreign object detection step, the presence or absence of magnetic foreign particles passing through the first and second transport positions, as well as the first timing when the magnetic foreign particles passed through the first magnetic sensor and the second timing when they passed through the second magnetic sensor, are detected from the first sensor signal and the second sensor signal. Therefore, in the operation timing acquisition step, these can be used to easily obtain the predicted arrival timing when the part of the inspected object being transported reaches the removal section.

[0020] (8) A foreign matter particle removal method as described in (7), wherein the foreign matter detection step comprises: a 1-2 difference acquisition step of acquiring a 1-2 difference signal which is the difference between the first sensor signal and the second sensor signal; a first foreign matter detection step of detecting from the 1-2 difference signal whether or not the magnetic foreign matter particle has passed through the first transport position and the first timing; and a second foreign matter detection step of detecting from the 1-2 difference signal whether or not the magnetic foreign matter particle has passed through the second transport position and the second timing.

[0021] Spare 3: Spare 1 compatible Furthermore, it is preferable to have a foreign particle removal method according to (7) or (8), wherein the object to be inspected is transported inside the piping, and the first magnetic sensor and the second magnetic sensor are located at a first circumferential position in the circumferential direction of the piping.

[0022] (9) A method for removing foreign particles according to (7) or (8), wherein the sensor signal acquisition step further uses a third magnetic sensor positioned at the first transport position, facing the first magnetic sensor via the object to be inspected, and outputting a third sensor signal indicating the presence or absence of magnetic foreign particles contained in the object to be transported, and a fourth magnetic sensor positioned at the second transport position, facing the second magnetic sensor via the object to be inspected, and outputting a fourth sensor signal indicating the presence or absence of magnetic foreign particles contained in the object to be transported, thereby acquiring the first to fourth sensor signals. The foreign object detection step involves acquiring a sensor signal and includes a 1-3 difference acquisition step for acquiring a 1-3 difference signal, which is the difference between the first sensor signal and the third sensor signal, and a 2-4 difference acquisition step for acquiring a 2-4 difference signal, which is the difference between the second sensor signal and the fourth sensor signal. The foreign object removal method involves detecting, from the 1-3 difference signal and the 2-4 difference signal, whether or not the magnetic foreign object particles have passed through the first transport position and the first timing, and whether or not the magnetic foreign object particles have passed through the second transport position and the second timing.

[0023] (10) Further, it is a foreign matter particle removal method described in (9), wherein the foreign matter detection step further includes a second-order difference signal acquisition step of acquiring a second-order difference signal that is the difference between the 1-3 difference signal and the second sensor signal, and from the second-order difference signal, the presence or absence of passage of the magnetic foreign matter particles at the first transport position and the first timing, and the presence or absence of passage of the magnetic foreign matter particles at the second transport position and the second timing are detected. It is preferable to adopt a foreign matter particle removal method.

[0024] Further, it is a foreign matter particle removal method described in (9) or (10), wherein the inspected object is being transported in a pipe, the first magnetic sensor and the second magnetic sensor are arranged at a first circumferential position in the circumferential direction of the pipe, and the third magnetic sensor and the fourth magnetic sensor are arranged at a second circumferential position on the opposite side of the first circumferential position in the circumferential direction. It is preferable to adopt a foreign matter particle removal method.

[0025] (11) Further, it is a foreign matter particle removal method described in any one of (7) to (10), wherein the removal part processing part is a removal part that removes the removal part from the inspected object, is arranged at a fourth transport position on the downstream side of the removal part, and for the inspected object from which the removal part has been removed and is being transported, a confirmation magnetic sensor that outputs a confirmation sensor signal indicating the presence or absence of passage of the magnetic foreign matter particles at the fourth transport position, and a confirmation step of detecting the presence or absence of passage of the magnetic foreign matter particles at the fourth transport position from the confirmation sensor signal are further provided. It is preferable to adopt a foreign matter particle removal method.

[0026] (12) Further, it is a foreign matter particle removal method described in any one of (7) to (11), wherein at a fifth transport position upstream of the first transport position in the transport direction, a magnetic field that is orthogonal to the transport direction and faces a first direction from the inspected object toward the first magnetic sensor is applied to the inspected object to magnetize metal foreign matter particles contained in the inspected object into the magnetic foreign matter particles, and a foreign matter magnetization step of delivering them to the first transport position is provided. It is preferable to adopt a foreign matter particle removal method.

Brief Description of the Drawings

[0027] [Figure 1] This is an explanatory diagram relating to Embodiments 1 and 2, and Modified Form 1, showing how magnetic foreign matter particles, which are magnetized metallic foreign matter particles contained in a paste flowing through a pipe, are detected by two or two pairs of magnetic sensors placed on the upstream and downstream sides. [Figure 2] This is a cross-sectional diagram taken along the line AA in Figure 1, showing the circumferential arrangement of the first and third magnetic sensors at the first transport position of the piping, relating to Embodiments 1 and 2 and Modified Form 1. [Figure 3] This is a cross-sectional diagram taken along the BB arrow in Figure 1, showing the circumferential arrangement of the second and fourth magnetic sensors at the second transport position of the piping, relating to Embodiments 1 and 2 and Modified Form 1. [Figure 4] This diagram illustrates the removal and confirmation of the removal of the part to be removed downstream of the second transport position in the piping, relating to Embodiments 1 and 2, and Modified Form 1. [Figure 5] This is a block diagram showing the configuration of a foreign particle removal device according to Embodiment 1. [Figure 6] This flowchart shows the processing flow of the foreign particle removal method according to Embodiment 1. [Figure 7] This graph shows two sensor signals, their difference signal, and two confirmation sensor signals, along with the time variation of their difference signal, relating to Embodiment 1. [Figure 8] This is a block diagram showing the configuration of the detection device according to Embodiment 2. [Figure 9] This is a flowchart showing the processing flow of the detection method according to Embodiment 2. [Figure 10] This graph, relating to Embodiment 2, shows the time evolution of four sensor signals, two difference signals, and a second-order difference signal. [Figure 11] This diagram illustrates the second deformation form, showing how, when magnetic foreign particles contained in the electrode layer of a strip-shaped electrode plate being transported are detected, a removal mark is placed on the removal area of ​​the strip-shaped electrode plate that contains the magnetic foreign particles to indicate that it is a removal area.

[0028] (Embodiment 1) Hereinafter, an embodiment 1 of the present invention will be described with reference to Figures 1 to 7, describing a foreign particle removal system 10 and a foreign particle removal method for detecting and removing magnetic foreign particles MP flowing inside a pipe PP. As shown in Figures 1 to 3, there are cases where a positive electrode paste IM, which is the object to be inspected, is transported by flowing it through a cylindrical pipe PP. Such a positive electrode paste IM is, for example, applied to an electrode foil and dried to form a positive electrode layer. Furthermore, an electrode plate having such a positive electrode layer is used to form a wound or laminated electrode body, which is then used to form an energy storage device such as a lithium-ion battery.

[0029] However, the positive electrode paste IM, which is the object under inspection and flows through the cylindrical PP pipe, may contain metallic foreign particles KP such as stainless steel particles or iron particles. If metallic foreign particles KP are present in the positive electrode layer that makes up the battery, they may dissolve in the electrolyte and precipitate as needle-shaped dendrites on the negative electrode plate, potentially causing malfunctions such as short circuits between the negative and positive electrode plates.

[0030] Therefore, it is desirable to detect and remove the presence or absence of metallic foreign particles KP in the positive electrode paste IM being transported through the piping PP. Specifically, the portion EP containing metallic foreign particles KP from the transported positive electrode paste IM is removed and discarded in the removal unit 50 described later. Alternatively, the portion EP to be removed may be returned to the piping PP for transport after the metallic foreign particles KP have been removed by passing it through a foreign matter removal filter (not shown).

[0031] In this embodiment 1, metallic foreign particles KP contained in the positive electrode paste IM flowing through the piping PP toward the downstream HHD in the transport direction HH are detected and removed by the foreign particle removal system 10. Note that metallic foreign particles KP are not necessarily magnetized. Therefore, in this embodiment 1, as shown in Figure 1, the magnetization unit 90 is placed at the fifth transport position HH5, which is upstream of the first transport position HH1 in the transport direction HH in the piping PP, where the first magnetic sensor 1, described later, is located. The magnetization unit 90 consists of an upper magnetization unit 90A comprising an air-core coil 91 and a drive power supply 93 connected thereto, and a lower magnetization unit 90B comprising an air-core coil 92 paired with the air-core coil 91 and a drive power supply 94 connected thereto. By passing current through the air-core coils 91 and 92, a magnetic field MF is generated in the piping PP, as shown by the upward arrow in Figure 1, which is perpendicular to the transport direction HH and points towards the upper DH1a of the first direction DH1 connecting the first magnetic sensor 1 and the third magnetic sensor 3, which will be described later. As a result, when metal foreign matter particles KP flow through the piping PP together with the positive electrode paste IM, the metal foreign matter particles KP are magnetized and become magnetic foreign matter particles MP. Specifically, as shown in Figure 1, the magnetic field MF generated in the magnetization unit 90 magnetizes the metal foreign matter particles KP into magnetic foreign matter particles MP with the upper side being the N pole and the lower side being the S pole. In addition, the positive electrode paste IM flows in a laminar flow within the piping PP. Therefore, when the positive electrode paste IM is transported downstream of the transport direction HH, towards HHD (to the right in Figure 1), as shown in Figure 1, the magnetic foreign matter particles MP are transported without rotating, maintaining their orientation with the upper side as the north pole and the lower side as the south pole.

[0032] In the piping PP, a first magnetic sensor 1 is positioned at the first transport position HH1 (see Figure 1) in the transport direction HH, on the downstream HHD of the magnetization section 90 described above, and at the first circumferential position CH1 (upper side in Figure 2) in the circumferential direction CH of the piping PP. Furthermore, a second magnetic sensor 2 is positioned at the second transport position HH2 (see Figure 1), which is downstream of the first transport position HH1 where the first magnetic sensor 1 is positioned, and at the same first circumferential position CH1 (upper side in Figure 3) in the circumferential direction CH of the piping PP as the first magnetic sensor 1. As a result, when magnetic foreign matter particles MP pass through the first transport position HH1 and the second transport position HH2, similar foreign matter component signals SG are generated in the first sensor signal S1(t) and the second sensor signal S2(t) (see Figure 7). Therefore, the passage of magnetic foreign matter particles MP through the first transport position HH1 and the second transport position HH2 can be detected with similar accuracy.

[0033] Furthermore, at the third transport position HH3 (see Figure 4), which is downstream of the second transport position HH2 where the second magnetic sensor 2 is located, a removal unit 50 is located to remove the part to be removed EP containing magnetic foreign matter particles MP. Furthermore, at the fourth transport position HH4, which is downstream of the third transport position HH3 where the removal unit 50 is located, and at the first circumferential position CH1 (upper side in Figure 4), which is the same as the first magnetic sensor 1 and the second magnetic sensor 2 in the circumferential direction CH of the piping PP, a confirmation magnetic sensor 5 is located.

[0034] The distance in the transport direction HH from the first transport position HH1 where the first magnetic sensor 1 is located to the second transport position HH2 where the second magnetic sensor 2 is located is the 1-2 distance L12. The distance in the transport direction HH from the second transport position HH2 to the third transport position HH3 where the removal unit 50 is located is the 2-3 distance L23.

[0035] Furthermore, at the fifth transport position HH5 (see Figure 1), the aforementioned air-core coil 91 is positioned at the upper first circumferential position CH1 of the circumferential direction CH of the piping PP, while the air-core coil 92 is positioned at the lower second circumferential position CH2, opposite to the first circumferential position CH1.

[0036] The foreign particle removal system 10 of this embodiment 1 includes, in addition to the magnetization unit 90, first and second magnetic sensors 1 and 2, removal unit 50, and confirmation magnetic sensor 5, a foreign object detection unit 40 and a confirmation unit 70 (see Figure 5). Of these, the first and second magnetic sensors 1 and 2 and the confirmation magnetic sensor 5 continuously output first and second sensor signals S1(t), S2(t), and confirmation sensor signal SC(t). Specifically, the first magnetic sensor 1 is located at the first transport position HH1 and the first circumferential position CH1, and outputs the change in magnetic force of the transported positive electrode paste IM at the first transport position HH1 as the first sensor signal S1(t). The second magnetic sensor 2 is located at the second transport position HH2 and the first circumferential position CH1, and outputs the change in magnetic force of the transported positive electrode paste IM at the second transport position HH2 as the second sensor signal S2(t). Furthermore, the confirmation magnetic sensor 5 is positioned at the fourth transport position HH4 and the first circumferential position CH1, and outputs the change in magnetic force at the second transport position HH2 of the transported positive electrode paste IM as the confirmation sensor signal SC(t). Note that the first and second sensor signals S1(t), S2(t) and the confirmation sensor signal SC(t) are all superimposed with a noise component NZ caused by an external magnetic field OM, i.e., an external magnetic field OM, as shown in the first, second, and fourth stages of Figure 7 (see Figures 1, 4, and 7).

[0037] External magnetic field changes OM refer to changes in magnetism that reach the detection range (not shown) of each magnetic sensor 1 and 2 from the outside. Examples include alternating magnetic fields of 50 Hz or 60 Hz emitted from nearby power lines, and changes in the surrounding magnetism caused by the rotation of motors located near each magnetic sensor. White noise-like magnetic changes are often also present.

[0038] The foreign object detection unit 40 includes a 1-2 difference acquisition unit 21, a first foreign object detection unit 41, a second foreign object detection unit 42, and an operation timing acquisition unit 60. Of these, the 1-2 difference acquisition unit 21 receives the first and second sensor signals S1(t) and S2(t) from the first and second magnetic sensors 1 and 2, which are aligned in the transport direction HH. The 1-2 difference acquisition unit 21 acquires the 1-2 difference signal D12(t), which is the difference between the first sensor signal S1(t) and the second sensor signal S2(t) (D12(t) = S1(t) - S2(t)). As shown in the third stage of Figure 7, by taking the difference between the first sensor signal S1(t) and the second sensor signal S2(t) in this 1-2 difference signal D12(t), much of the noise component NZ caused by the foreign magnetic OM that is commonly included can be canceled, and the noise component included in the 1-2 difference signal D12(t) can be suppressed. Conversely, the signal-to-noise ratio (SNR) increases, and the signal change associated with the passage of magnetic foreign particles MP at the first transport position HH1 can be clearly obtained in the 1-2 difference signal D12(t). Furthermore, the signal change associated with the passage of magnetic foreign particles MP at the second transport position HH2 can also be clearly obtained.

[0039] Therefore, by using this 1-2 difference signal D12(t), it is possible to suppress the noise component NZ caused by changes in the external magnetic field OM included in the first sensor signal S1(t) and the second sensor signal S2(t), while sensitively detecting the presence or absence of magnetic foreign particles MP passing through the first transport position HH1 and the second transport position HH2, as well as their timings t1 and t2.

[0040] Specifically, the first foreign object detection unit 41 uses the 1-2 difference signal D12(t) to detect the passage of magnetic foreign object particles MP at the first transport position HH1. That is, as shown in the third stage of Figure 7, the 1-2 difference signal D12(t) is monitored, and it is determined that there are magnetic foreign object particles MP that have passed through the first transport position HH1 at the first timing t1 when this 1-2 difference signal D12(t) exceeds the upper threshold value, the first threshold value TH1 (TH1>0), or falls below the lower threshold value, the second threshold value TH2 (TH2<0).

[0041] Next, the second foreign object detection unit 42 also uses the 1-2 difference signal D12(t) to detect the passage of magnetic foreign object particles MP at the second transport position HH2. Specifically, if the first foreign object detection unit 41 determines that there are magnetic foreign object particles MP that have passed the first transport position HH1 at the first timing t1, then at the second timing t2, which is within the delay time range TDP including a predetermined delay time TD, if the 1-2 difference signal D12(t) exceeds the first threshold TH1 or falls below the second threshold TH2, it is determined that there are magnetic foreign object particles MP that have passed the second transport position HH2 at the second timing t2. In other cases, i.e., if the second timing t2 for detecting the passage of magnetic foreign object particles MP at the second transport position HH2 is not obtained within the delay time range TDP, or if it is obtained outside the delay time range TDP, it is treated as an abnormal value and ignored.

[0042] Furthermore, the activation timing acquisition unit 60 obtains an activation timing t3 for activating the removal unit 50 located at the third transport position from the first timing t1 and the second timing t2. As mentioned above, the distance L12 of 1-2 in the transport direction HH from the first transport position HH1 to the second transport position HH2, and the distance L23 of 2-3 in the transport direction HH from the second transport position HH2 to the third transport position HH3 are known. Therefore, the activation timing t3 at which the magnetic foreign particle MP is expected to reach the removal unit 50 located at the third transport position HH3 is given by t3 = t2 + (L23·(t2-t1) / L12). Thus, the activation timing acquisition unit 60 presents the activation timing t3 at which the magnetic foreign particle MP is expected to reach the removal unit 50 to the removal unit 50.

[0043] The removal section 50 is the part that removes the portion to be removed EP, which contains magnetic foreign matter particles MP detected by the first foreign matter detection section 41 and the second foreign matter detection section 42, from the positive electrode paste IM being transported in the transport direction HH within the piping PP. Specifically, it is a reject valve that temporarily switches the flow path of the positive electrode paste IM away from the piping PP and discharges the portion to be removed EP, which contains magnetic foreign matter particles MP, from the positive electrode paste IM to the outside of the piping PP.

[0044] Specifically, the flow path is switched for a predetermined discharge period including the operating timing t3 to discharge the part to be removed EP containing magnetic foreign particles MP outside the piping PP. The discharged part to be removed EP, which is the positive electrode paste IM, is discarded. Alternatively, the part to be removed EP can be passed through a separately prepared foreign matter removal filter to remove the magnetic foreign particles MP, and then returned to the piping PP as positive electrode paste IM. In this case, it is preferable to return it to the piping PP upstream of the magnetization section 90 HHU, and then detect and remove the magnetic foreign particles MP again using the foreign matter particle removal system 10 of this embodiment.

[0045] Next, the confirmation unit 70 will be described. In the piping PP, the aforementioned confirmation magnetic sensor 5 is positioned at the fourth transport position HH4 of the HHD downstream of the removal unit 50. As mentioned above, the part to be removed EP containing magnetic foreign particles MP should have been discharged to the outside of the piping PP by the removal unit 50, and the positive electrode paste IM transported downstream of the removal unit 50 in the HHD should not contain magnetic foreign particles MP. Therefore, the confirmation unit 70 uses the confirmation sensor signal SC(t) from the confirmation magnetic sensor 5 to detect whether or not magnetic foreign particles MP have passed through the fourth transport position HH4. That is, if magnetic foreign particles MP do not pass through the fourth transport position HH4, a flat output is maintained, as shown by the solid line in the fourth stage of Figure 7. Thus, the positive electrode paste IM, from which the part to be removed EP containing magnetic foreign particles MP has been confirmed to have been removed, can be transported further downstream.

[0046] However, if magnetic foreign particles MP pass through the fourth transport position HH4, a foreign matter component signal SG appears around the fourth timing t4 of the confirmation sensor signal SC(t), as shown by the dashed line in the fourth stage of Figure 7. Note that the appearance of the foreign matter component signal SG in the confirmation sensor signal SC(t) is an abnormality that is not normally expected. For example, the positive electrode paste IM, which has been temporarily stored in the downstream HHD of the piping PP, is passed through a separately prepared foreign matter removal filter to remove the magnetic foreign particles MP, and then returned as positive electrode paste IM to the piping PP upstream of the magnetization section 90 HHU, and passed through the foreign matter particle removal system 10 of this embodiment again.

[0047] Furthermore, as shown in the fourth stage of Figure 7, the confirmation sensor signal SC(t) is superimposed with a noise component NZ due to an external magnetic field OM. Depending on the magnitude of the superimposed noise component NZ, it may be difficult to properly detect the foreign matter component signal SG using only the confirmation sensor signal SC(t). In this case, as shown by the dashed line in Figure 4, a second confirmation magnetic sensor 6 is placed at the fourth transport position HH4 of the piping PP, at the second circumferential position CH2 (lower side in Figure 4), which is on the opposite side from the first circumferential position CH1 in the circumferential direction CH of the piping PP, with the positive electrode paste IM and the piping PP in between, facing the confirmation magnetic sensor 5.

[0048] Then, as shown by the dashed line in Figure 5, the difference acquisition unit 71 acquires a confirmation difference signal DC(t), which is the difference between the confirmation sensor signal SC(t) of the confirmation magnetic sensor 5 and the confirmation second sensor signal SC2(t) of the confirmation second magnetic sensor 6. The confirmation unit 70 may use this confirmation difference signal DC(t) to detect whether or not magnetic foreign particles MP have passed through the fourth transport position HH4. In this way, as shown in the 4th to 6th stages of Figure 7, by taking the difference between the confirmation sensor signal SC(t) and the confirmation second sensor signal SC2(t), much of the noise component NZ due to the foreign magnetic OM that is commonly included can be canceled, and the noise component included in the confirmation difference signal DC(t) can be suppressed. Conversely, the signal-to-noise ratio becomes larger, and the signal change associated with the passage of magnetic foreign particles MP at the fourth transport position HH4 can be clearly obtained in the confirmation difference signal DC(t).

[0049] Next, the method for removing foreign particles according to this embodiment 1 will be described (see Figure 6). First, in the foreign matter magnetization step ST0, the magnetization unit 90 generates a magnetic field MF inside the piping PP at the fifth transport position HH5. This magnetizes the metallic foreign particles KP transported together with the positive electrode paste IM, converting them into magnetic foreign particles MP.

[0050] In the subsequent sensor signal acquisition step ST1, the first and second sensor signals S1(t) and S2(t) of the first and second magnetic sensors 1 and 2 are continuously acquired in the two sensor acquisition steps ST1a and ST1b included therein.

[0051] In the foreign object detection step ST3, the difference signal acquisition step ST2 acquires the 1-2 difference signal D12(t), which is the difference between the first sensor signal S1(t) and the second sensor signal S2(t).

[0052] Next, in the foreign object detection step ST3, the first foreign object detection step ST3a uses the 1-2 difference signal D12(t) to determine whether or not a magnetic foreign object particle MP has passed through the first transport position HH1, and to obtain the first timing t1 when the magnetic foreign object particle MP has passed through the first transport position HH1. Specifically, if the 1-2 difference signal D12(t) exceeds the first threshold TH1 or falls below the second threshold TH2, it is determined that the magnetic foreign object particle MP has passed through the first transport position HH1 at the first timing t1.

[0053] Furthermore, in the second foreign object detection step ST3b, the 1-2 difference signal D12(t) is used to determine whether or not a magnetic foreign object particle MP has passed through the second transport position HH2, and the second timing t2, when the magnetic foreign object particle MP has passed through the second transport position HH2, is obtained. Specifically, if the 1-2 difference signal D12(t) exceeds the first threshold TH1 or falls below the second threshold TH2 within the delay time range TDP measured from the first timing t1, it is determined that the magnetic foreign object particle MP has passed through the second transport position HH2 at the second timing t2.

[0054] The explanation will use the example graphs shown in the first to third rows of Figure 7. In the following, we assume that magnetic foreign particles MP magnetized by the magnetization unit 90 pass through the first transport position HH1 at the first timing t1, and then pass through the second transport position HH2 at the second timing t2. The positive electrode paste IM transported through the piping PP is transported laminarly at a constant transport speed (flow velocity) Vh, and the distance HH in the transport direction from the first transport position HH1 to the second transport position HH2 is denoted as the 1-2 distance L12. Then, the second timing t2 arrives approximately 1st timing t1 with a delay time TD (TD = L12 / Vh).

[0055] The graphs in the first and second rows of Figure 7 show the first and second sensor signals S1(t) and S2(t) obtained from the first and second magnetic sensors 1 and 2, respectively. As mentioned above, at the first timing t1, the magnetic foreign particle MP passes through the first transport position HH1. Therefore, the first sensor signal S1(t) has a foreign component signal SG generated before and after the first timing t1. Each magnetic sensor 1, 2, 5, and 6 has the characteristic of generating a positive signal when the north pole of the magnetic foreign particle MP approaches and a negative signal when it moves away, and a negative signal when the south pole approaches and a positive signal when it moves away.

[0056] Therefore, in the first sensor signal S1(t), before the first timing t1 when the magnetic foreign particle MP passes the first transport position HH1, the north pole first approaches the first magnetic sensor 1 (see Figures 1 and 2), resulting in a positive signal. Subsequently, at the first timing t1, the north pole moves away from the first magnetic sensor 1, resulting in a negative signal. That is, a foreign component signal SG is generated (see the first stage of Figure 7). Note that there is no change in the second sensor signal S2(t) before and after the first timing t1 (see the second stage of Figure 7). This is because, from the perspective of the second magnetic sensor 2, the magnetic foreign particle MP has not yet approached. In addition, the first and second sensor signals S1(t) and S2(t) are always accompanied by a noise component NZ caused by the external magnetic field OM.

[0057] On the other hand, in the second sensor signal S2(t), before the second timing t2 when the magnetic foreign particle MP passes the second transport position HH2, the north pole approaches the second magnetic sensor 2 (see Figures 1 and 2), so a positive signal is first obtained. Then, at the second timing t2, the north pole moves away from the second magnetic sensor 2, so a negative signal is obtained. That is, a foreign component signal SG is generated (see the second stage of Figure 7). Note that there is no change in the first sensor signal S1(t) before and after the second timing t2. This is because, from the perspective of the first and third magnetic sensors 1 and 3, the magnetic foreign particle MP has already passed through.

[0058] The third graph in Figure 7 shows the 1-2 difference signal D12(t) obtained by subtracting the second sensor signal S2(t) from the first sensor signal S1(t). In the 1-2 difference signal D12(t), the noise component NZ, which is common to both the first sensor signal S1(t) and the second sensor signal S2(t), is subtracted, and the noise component is suppressed. On the other hand, the foreign matter component signal SG that occurs in the first sensor signal S1(t) around the first timing t1, and the foreign matter component signal SG that occurs in the second sensor signal S2(t) around the second timing t2, remain in the 1-2 difference signal D12(t). Therefore, the signal-to-noise ratio of the 1-2 difference signal D12(t) is significantly improved compared to the first and second sensor signals S1(t) and S2(t).

[0059] Therefore, in the first foreign object detection step ST3a, as shown in the third stage of Figure 7, the 1-2 difference signal D12(t) is monitored, and if the 1-2 difference signal D12(t) exceeds the upper threshold, the first threshold TH1 (TH1>0), or falls below the lower threshold, the second threshold TH2 (TH2<0), it is determined that the magnetic foreign object particle MP has passed the first transport position HH1. This makes it possible to reliably determine that the magnetic foreign object particle MP has passed the first transport position HH1 around the first timing t1.

[0060] Furthermore, around the second timing t2 when the magnetic foreign particle MP passes the second transport position HH2, the 1-2 difference signal D12(t) exceeds the first threshold TH1 or falls below the second threshold TH2. Therefore, in this embodiment, if the passage of the magnetic foreign particle MP is already detected at the first timing t1, if the 1-2 difference signal D12(t) exceeds the first threshold TH1 or falls below the second threshold TH2 at the second timing t2 within the delay time range TDP including the aforementioned delay time TD, it is determined that there is a magnetic foreign particle MP that has passed the second transport position HH2 at this second timing t2.

[0061] Next, in the activation timing acquisition step ST4, the activation timing t3 for activating the removal unit 50 located at the third transport position is obtained from the first timing t1 and the second timing t2. As mentioned above, the activation timing t3 at which the magnetic foreign particle MP is expected to reach the removal unit 50 located at the third transport position HH3 is given by t3 = t2 + (L23·(t2-t1) / L12).

[0062] In the subsequent removal step ST5, the portion to be removed EP, which contains magnetic foreign matter particles MP detected by the first foreign matter detection unit 41 and the second foreign matter detection unit 42, is removed from the positive electrode paste IM being transported in the transport direction HH within the piping PP. Specifically, for a discharge period including the operation timing t3 obtained in the processing unit operation step ST5, the reject valve, which is the removal unit 50, temporarily switches the flow path of the positive electrode paste IM away from the piping PP, and discharges the portion to be removed EP containing magnetic foreign matter particles MP from the positive electrode paste IM outside the piping PP.

[0063] Next, in the confirmation step ST6, the presence or absence of magnetic foreign matter particles MP passing through the fourth transport position HH4 is detected from the confirmation sensor signal SC(t) of the positive electrode paste IM, from which the part to be removed EP has been removed and which is being transported in the transport direction HH. Specifically, first, in the confirmation signal acquisition step ST6a, the confirmation sensor signal SC(t) of the confirmation magnetic sensor 5 located at the fourth transport position HH4 of the HHD downstream side of the removal section 50 in the piping PP is acquired.

[0064] In the subsequent pass-through determination step ST6b, the confirmation sensor signal SC(t) shown in the fourth stage of Figure 7 is monitored, and it is confirmed whether the foreign matter component signal SG, as shown by the dashed line, appears in this confirmation sensor signal SC(t), that is, whether the part to be removed EP containing magnetic foreign matter particles MP has been removed from the positive electrode paste IM being transported in the pipe PP. If the foreign matter component signal SG does not appear in the confirmation sensor signal SC(t) (Yes), the foreign matter particle removal method of this embodiment 1 is applied to the positive electrode paste IM that is being transported further. On the other hand, if the foreign matter component signal SG, as shown by the dashed line in the fourth stage of Figure 7, appears in the confirmation sensor signal SC(t), the process proceeds to the defective processing step ST6c, where the positive electrode paste IM containing magnetic foreign matter particles MP is processed.

[0065] Furthermore, if the noise component NZ included in the verification sensor signal SC(t) is large, the following procedure may be followed. That is, as shown in the 4th to 6th steps of Figure 7, in parallel with the acquisition of the verification sensor signal SC(t) in the verification signal acquisition step ST6a, the second verification sensor signal SC2(t) of the aforementioned second verification magnetic sensor 6 is acquired in the second verification signal acquisition step ST6d.

[0066] Subsequently, in the confirmation difference acquisition step ST6e, the confirmation difference signal DC(t), which is the difference between the confirmation sensor signal SC(t) and the confirmation second sensor signal SC2(t), is acquired. In the passage determination step ST6b, the confirmation difference signal DC(t) shown in the sixth stage of Figure 7 is monitored, and it is confirmed that the foreign object component signal SG+SG', as shown by the dashed line, does not appear in this confirmation difference signal DC(t).

[0067] (Embodiment 2) In the above-described embodiment 1, a first magnetic sensor 1 positioned at the first transport position HH1 and a second magnetic sensor 2 positioned at the second transport position HH2 downstream of HHD are used to determine whether or not magnetic foreign matter particles MP have passed through the first transport position HH1 and the second transport position HH2, and to obtain a first timing t1 and a second timing t2.

[0068] In contrast, the foreign particle removal system 110 and foreign particle removal method of the second embodiment, which will be described with reference to Figures 1 to 4 and Figures 8 to 10, also uses a third magnetic sensor 3 facing the first magnetic sensor 1 and a fourth magnetic sensor 4 facing the second magnetic sensor 2, using a total of four magnetic sensors to determine whether or not magnetic foreign particles MP have passed through the first transport position HH1 and the second transport position HH2, and to obtain the first timing t1 and the second timing t2. In this second embodiment, the explanation will focus on the parts that differ from the first embodiment described above, and similar parts will be omitted or simplified in their explanation.

[0069] In the foreign particle removal system 110 of this second embodiment (see Figures 1 to 4), the same magnetization unit 90 as in the first embodiment is used. In addition to a first magnetic sensor 1 being placed at the first transport position HH1 of the downstream HHD of the magnetization unit 90, a third magnetic sensor 3 is provided, as shown by the dashed lines in Figures 1 and 2, which is positioned opposite the first magnetic sensor 1 via the piping PP and the transported positive electrode paste IM, and outputs a third sensor signal S3(t) indicating the presence or absence of magnetic foreign particles MP contained in the transported positive electrode paste IM. This third magnetic sensor 3 is positioned at the second circumferential position CH2 (lower side in Figure 2) of the circumferential direction CH of the piping PP, 180 degrees opposite the first circumferential position CH1 where the first magnetic sensor 1 is located.

[0070] Furthermore, a second magnetic sensor 2 is positioned at the second transport position HH2, downstream of the first transport position HH1 (HHD). In addition, as shown by the dashed lines in Figures 1 and 3, a fourth magnetic sensor 4 is positioned opposite the second magnetic sensor 1 via the piping PP and the transported positive electrode paste IM, and outputs a fourth sensor signal S4(t) indicating the presence or absence of magnetic foreign particles MP in the positive electrode paste IM. This fourth magnetic sensor 4 is also positioned at the same second circumferential position CH2 (lower side in Figure 3) as the third magnetic sensor 3. As a result, when magnetic foreign particles MP pass through the first transport position HH1 and the second transport position HH2, similar foreign particle component signals SG are generated in the first sensor signal S1(t) and the second sensor signal S2(t). Also, similar foreign particle component signals SG are generated in the third sensor signal S3(t) and the fourth sensor signal S4(t) (see Figure 10). Therefore, the passage of magnetic foreign particles MP through the first transport position HH1 and the second transport position HH2 can be detected with similar accuracy.

[0071] Furthermore, similar to Embodiment 1, a removal unit 50 is located at the third transport position HH3 downstream of the second transport position HH2, and a confirmation magnetic sensor 5 is located at the fourth transport position HH4. In addition to the confirmation magnetic sensor 5, a second confirmation magnetic sensor 6 may also be used.

[0072] The foreign particle removal system 110 of this second embodiment includes, in addition to the magnetization unit 90, the first to fourth magnetic sensors 1 to 4, the removal unit 50, and the confirmation magnetic sensor 5, a foreign object detection unit 140 and a confirmation unit 70 (see Figure 5). Of these, the first to fourth magnetic sensors 1 to 4 continuously output the first to fourth sensor signals S1(t) to S4(t). As shown in the first to fourth stages of Figure 10, the first to fourth sensor signals S1(t) to S4(t) are all superimposed with changes in the external magnetic field OM, i.e., noise components NZ due to the external magnetic field OM (see Figures 1 and 10).

[0073] Unlike Embodiment 1, which included a 1-2 difference acquisition unit 21, the foreign object detection unit 140 includes a 1-3 difference acquisition unit 122, a 2-4 difference acquisition unit 123, as well as a first foreign object detection unit 141, a second foreign object detection unit 142, and an operation timing acquisition unit 60. Of these, the 1-3 difference acquisition unit 122 receives the first and third sensor signals S1(t) and S3(t) from the first and third magnetic sensors 1 and 3, which are facing each other at the first transport position HH1. The 1-3 difference acquisition unit 122 acquires the 1-3 difference signal D13(t), which is the difference between the first sensor signal S1(t) and the third sensor signal S3(t) (D13(t) = S1(t) - S3(t)). As shown in the fifth step of Figure 10, in this 1-3 difference signal D13(t), by taking the difference between the first sensor signal S1(t) and the third sensor signal S3(t), much of the noise component NZ caused by the foreign magnetic OM commonly present can be canceled, and the noise component contained in the 1-3 difference signal D13(t) can be suppressed. Moreover, in the 1-3 difference signal D13(t), the foreign object signal component SG generated in the first sensor signal S1(t) due to the passage of magnetic foreign object particles MP at the first transport position HH1 and the foreign object signal component SG' generated in the third sensor signal S3(t) can be added together and increased, further improving the signal-to-noise ratio. Therefore, by using this 1-3 difference signal D13(t), it is possible to sensitively detect the presence or absence of magnetic foreign object particles MP passing at the first transport position HH1 and its first timing t1 while suppressing the noise component NZ contained in the first and third sensor signals S1(t) and S3(t).

[0074] On the other hand, the 2-4 difference acquisition unit 123 receives the second and fourth sensor signals S2(t) and S4(t) from the second and fourth magnetic sensors 2 and 4, which are facing each other at the second transport position HH2, and acquires the 2-4 difference signal D24(t), which is the difference between these signals (D24(t) = S2(t) - S4(t)). As shown in the sixth stage of Figure 10, even with this 2-4 difference signal D24(t), by taking the difference between the two signals, much of the noise component NZ caused by the foreign magnetic OM that is commonly included can be canceled, and the noise component included in the 2-4 difference signal D24(t) can be suppressed. Moreover, even with the 2-4 difference signal D24(t), the foreign object signal component SG that is generated in the second sensor signal S2(t) due to the passage of magnetic foreign object particles MP through the second transport position HH2 and the foreign object signal component SG' that is generated in the fourth sensor signal S4(t) can be added together and increased. Therefore, by using this 2-4 difference signal D24(t), it is possible to suppress the noise component NZ contained in the second and fourth sensor signals S2(t) and S4(t), while sensitively detecting whether or not magnetic foreign particles MP pass through the second transport position HH2 and their second timing t2.

[0075] The first foreign object detection unit 141 uses the 1-3 difference signal D13(t) to detect the passage of magnetic foreign object particles MP at the first transport position HH1. Specifically, as shown in the fifth step of Figure 10, it is determined that there are magnetic foreign object particles MP that have passed through the first transport position HH1 at the first timing t1 when the 1-3 difference signal D13(t) exceeds the upper threshold, the third threshold TH3 (TH3>0), or falls below the lower threshold, the fourth threshold TH4 (TH4<0).

[0076] Next, the second foreign object detection unit 142 also uses the 2-4 difference signal D24(t) to detect the passage of magnetic foreign object particles MP at the second transport position HH2. Specifically, as shown in the sixth stage of Figure 10, it is determined that there are magnetic foreign object particles MP that have passed through the second transport position HH2 at the second timing t2 when the 2-4 difference signal D24(t) exceeds the third threshold TH3 or falls below the fourth threshold TH4.

[0077] As can be easily understood from the 5th and 6th stages of Figure 10, at the first timing t1 when the magnetic foreign particle MP passes the first transport position HH1, no signal change occurs in the 2-4 difference signal D24(t). Similarly, at the second timing t2 when the magnetic foreign particle MP passes the second transport position HH2, no signal change occurs in the 1-3 difference signal D13(t). Therefore, processing that considers the delay time TD and delay time range TDP, as in the 1-2 difference signal D12(t) in Embodiment 1, is unnecessary.

[0078] However, as in Embodiment 1, the same magnetic foreign particle MP should be detected at both the first timing t1 and the second timing t2. Therefore, if the first foreign object detection unit 141 detects a magnetic foreign particle MP at the first timing t1, it is possible to determine whether the second timing t2 exists within the delay time range TDP, which includes the delay time TD, measured from the first timing t1, and to consider the detection correct only if the second timing t2 exists within the delay time range TDP.

[0079] The processing in the operation timing acquisition unit 60, removal unit 50, and confirmation unit 70 in this embodiment 2 is the same as in embodiment 1. That is, the operation timing acquisition unit 60 obtains an operation timing t3 for activating the removal unit 50 located at the third transport position from the first timing t1 and the second timing t2, and presents the operation timing t3, which is predicted to be when the magnetic foreign matter particles MP reach the removal unit 50, to the removal unit 50.

[0080] In the removal section 50, the removal section EP containing magnetic foreign matter particles MP detected by the first foreign matter detection section 41 and the second foreign matter detection section 42 is removed and discharged from the positive electrode paste IM being transported in the transport direction HH within the pipe PP.

[0081] Furthermore, the verification unit 70 detects whether or not magnetic foreign particles MP have passed through the fourth transport position HH4 from the verification sensor signal SC(t) output from the verification magnetic sensor 5.

[0082] Next, the method for removing foreign particles according to this second embodiment will be described (see Figure 9). In the foreign matter magnetization step ST0, as in the first embodiment, the magnetization unit 90 magnetizes the metallic foreign particles KP that were transported together with the positive electrode paste IM at the fifth transport position HH5, converting them into magnetic foreign particles MP.

[0083] In the subsequent sensor signal acquisition step ST1, the first to fourth sensor signals S1(t) to S4(t) of the first to fourth magnetic sensors 1 to 4 are continuously acquired in the four sensor acquisition steps ST1a to ST1d included therein.

[0084] In the foreign object detection step ST13, the 1-3 difference signal acquisition step ST12a acquires the 1-3 difference signal D13(t), which is the difference between the first sensor signal S1(t) and the third sensor signal S3(t). In addition, the 2-4 difference signal acquisition step ST12b acquires the 2-4 difference signal D24(t), which is the difference between the second sensor signal S2(t) and the fourth sensor signal S4(t).

[0085] Next, in the foreign object detection step ST13, in the first foreign object detection step ST13a, the 1-3 difference signal D13(t) is used to determine whether or not a magnetic foreign object particle MP has passed through the first transport position HH1, and the first timing t1 when the magnetic foreign object particle MP has passed through the first transport position HH1 is obtained. In the second foreign object detection step ST13b, the 2-4 difference signal D24(t) is used to determine whether or not a magnetic foreign object particle MP has passed through the second transport position HH2, and the second timing t2 when the magnetic foreign object particle MP has passed through the second transport position HH2 is obtained.

[0086] The explanation will use the example graphs shown in the first to sixth rows of Figure 10. In the following, we assume that magnetic foreign particles MP magnetized by the magnetization unit 90 pass through the first transport position HH1 at the first timing t1, and then pass through the second transport position HH2 at the second timing t2. The positive electrode paste IM transported through the pipe PP is transported laminarly at a constant transport speed (flow velocity) Vh, and the distance HH in the transport direction from the first transport position HH1 to the second transport position HH2 is denoted as the 1-2 distance L12. Then, the second timing t2 arrives approximately 1 time t1 with a delay time TD (TD = L12 / Vh).

[0087] The graphs shown in the first to fourth rows of Figure 10 show the first to second sensor signals S1(t) to S4(t) obtained from the first to fourth magnetic sensors 1 to 4. As mentioned above, at the first timing t1, the magnetic foreign particle MP passes through the first transport position HH1. Therefore, the first and third sensor signals S1(t) and S3(t) have a foreign substance component signal SG or a foreign substance component signal SG in the opposite phase generated before and after the first timing t1. Similarly, the second and fourth sensor signals S2(t) and S4(t) have a foreign substance component signal SG or a foreign substance component signal SG in the opposite phase generated before and after the second timing t2.

[0088] Each magnetic sensor 1 to 4 has the characteristic of generating a positive signal when the north pole of the magnetic foreign particle MP approaches and a negative signal when it moves away, and a negative signal when the south pole approaches and a positive signal when it moves away. In addition, the first to fourth sensor signals S1(t) to S4(t) are always accompanied by a noise component NZ caused by the external magnetic field OM.

[0089] The fifth graph in Figure 10 shows the 1-3 difference signal D13(t). In the 1-3 difference signal D13(t), the noise component NZ, which is commonly present in the first sensor signal S1(t) and the third sensor signal S3(t), is subtracted, thereby suppressing the noise component. On the other hand, the foreign matter component signal SG that occurs in the first sensor signal S1(t) and the foreign matter component signal SG' that occurs in the third sensor signal S3(t) around the first timing t1 are added together in the 1-3 difference signal D13(t). As a result, the signal-to-noise ratio of the 1-3 difference signal D13(t) is significantly improved compared to the 1-2 difference signal D12(t) of Embodiment 1.

[0090] Therefore, in the first foreign object detection step ST13a, as shown in the fifth stage of Figure 10, if the 1-3 difference signal D13(t) exceeds the third threshold TH3 or falls below the fourth threshold TH4, it is determined that the magnetic foreign object particle MP has passed the first transport position HH1. This makes it possible to reliably determine that the magnetic foreign object particle MP has passed the first transport position HH1 around the first timing t1.

[0091] On the other hand, the sixth graph in Figure 10 shows the 2-4 difference signal D24(t). In this 2-4 difference signal D24(t), the noise component NZ common to the second sensor signal S2(t) and the fourth sensor signal S4(t) is subtracted and suppressed. Meanwhile, the foreign matter component signal SG generated in the second sensor signal S2(t) and the foreign matter component signal SG' generated in the fourth sensor signal S4(t) around the second timing t2 are added together in the 2-4 difference signal D24(t). As a result, the signal-to-noise ratio of the 2-4 difference signal D24(t) is significantly improved compared to the 1-2 difference signal D12(t) of Embodiment 1.

[0092] Therefore, in the second foreign object detection step ST13b, as shown in the sixth stage of Figure 10, if the 2-4 difference signal D24(t) exceeds the third threshold TH3 or falls below the fourth threshold TH4, it is determined that the magnetic foreign object particle MP has passed the second transport position HH2. This makes it possible to reliably determine that the magnetic foreign object particle MP has passed the second transport position HH2 around the second timing t2.

[0093] The subsequent steps of acquiring the operating timing ST4, removing ST5, and confirming ST6 are the same as in Embodiment 1. Specifically, in the operating timing acquisition step ST4, the operating timing t3 for activating the removal unit 50 located at the third transport position is obtained from the first timing t1 and the second timing t2. In the removal step ST5, the portion to be removed EP containing magnetic foreign matter particles MP detected by the first foreign matter detection unit 141 and the second foreign matter detection unit 142 is removed and discharged from the positive electrode paste IM being transported in the transport direction HH within the piping PP. Furthermore, in the confirmation step ST6, the presence or absence of magnetic foreign matter particles MP passing through the fourth transport position HH4 is detected from the confirmation sensor signal SC(t) for the positive electrode paste IM from which the portion to be removed EP has been removed and being transported in the transport direction HH.

[0094] (Transformation form 1) In the foreign particle removal system 110 of the above-described embodiment 2, four magnetic sensors, the first to fourth magnetic sensors 1 to 4, are used. Then, using two difference signals, the 1-3 difference signal D13(t) and the 2-4 difference signal D24(t), the first and second timings t1 and t2 are obtained to predict the operation timing t3. At this operation timing t3, the removal unit 50 is activated to remove and discharge the part to be removed EP containing magnetic foreign particles MP.

[0095] In contrast, the foreign particle removal system 111 of this modified form 1 acquires a second-order difference signal DD(t) from the 1-3 difference signal D13(t) and the 2-4 difference signal D24(t), and uses this second-order difference signal DD(t) to obtain the first and second timings t1 and t2. That is, as shown by the dashed line in Figure 8, the second-order difference signal acquisition unit 130 acquires the second-order difference signal DD(t) from the 1-3 difference signal D13(t) acquired by the 1-3 difference signal acquisition unit 122 and the 2-4 difference signal D24(t) acquired by the 2-4 difference signal acquisition unit 123 (see the 7th stage of Figure 10). Furthermore, as shown by the dashed line in Figure 9, in the second-order difference signal acquisition step ST7, the second-order difference signal DD(t) is obtained from the 1-3 difference signal D13(t) acquired in the 1-3 difference signal acquisition step 12a and the 2-4 difference signal D24(t) acquired in the 2-4 difference signal acquisition step ST12b.

[0096] By obtaining a second-order difference signal DD(t) from the two difference signals D13(t) and D24(t) in this way, noise components that occur in phase in both signals, which could not be removed at the stage of obtaining the 1-3 difference signal D13(t) and the 2-4 difference signal D24(t), are also removed. Therefore, the first foreign object detection unit 141 and the second foreign object detection unit 142 can use this second-order difference signal DD(t) to more reliably determine whether or not magnetic foreign object particles MP have passed through the first transport position HH1 and the second transport position HH2.

[0097] Specifically, the first foreign object detection unit 141 and the first foreign object detection step ST13a use a second-order difference signal DD(t) instead of a first-to-third difference signal D13(t) to detect the passage of magnetic foreign object particles MP at the first transport position HH1. More precisely, as shown in the seventh stage of Figure 10, it is determined that there are magnetic foreign object particles MP that have passed through the first transport position HH1 at the first timing t1 when the second-order difference signal DD(t) exceeds the third threshold TH3 or falls below the fourth threshold TH4.

[0098] Furthermore, in the second foreign object detection unit 142 and the second foreign object detection step ST13b, the passage of magnetic foreign object particles MP at the second transport position HH2 is detected using the second-order difference signal DD(t) instead of the 2-4 difference signal D24(t). Specifically, if the first foreign object detection unit 141 determines that there are magnetic foreign object particles MP that have passed the first transport position HH1 at the first timing t1, then at the second timing t2, which is within the delay time range TDP measured from the first timing t1, if the second-order difference signal DD(t) exceeds the third threshold TH3 or falls below the fourth threshold TH4, it is determined that there are magnetic foreign object particles MP that have passed the second transport position HH2 at the second timing t2.

[0099] Subsequently, the same processing is carried out in the operation timing acquisition unit 60, removal unit 50, and confirmation unit 70 as in embodiments 1 and 2.

[0100] (Transformation form 2) In Embodiments 1 and 2 and Modified Embodiment 1, first and second timings t1 and t2 were acquired, and after the operation timing acquisition unit 60 predicted the operation timing t3, the removal unit 50 removed the part to be removed EP containing magnetic foreign matter particles MP from the positive electrode paste IM and discharged it.

[0101] However, depending on the object being transported, it may be impossible to remove the removal area EP containing magnetic foreign particles MP during transport. Furthermore, there may be cases where it is necessary to initially only confirm the location of the magnetic foreign particles MP, and then separately remove the removal area EP containing the magnetic foreign particles MP. For example, this could occur in a long, strip-shaped electrode plate with a strip-shaped active material layer, where the strip-shaped active material layer contains magnetic foreign particles MP. In such cases, it is conceivable to mark the removal area containing the magnetic foreign particles MP on the object being transported, or on a marked area in a predetermined positional relationship to this removal area, to indicate the location of the removal area.

[0102] For example, in the elongated strip-shaped electrode plate FP shown in Figure 11, a strip-shaped active material layer FE is formed on both sides of an elongated strip-shaped electrode foil FF that is long in the longitudinal direction LH, and the edges of both ends of the electrode foil FF in the width direction WH are exposed strip-shaped exposed portions FFe1 and FFe2. Let's consider the case where such an elongated strip-shaped electrode plate FP is transported with the longitudinal direction LH as the transport direction HH, and magnetic foreign matter particles MP contained in the active material layer FE are detected. In this case, instead of the removal portion 50 shown in Figures 5 and 8 of Embodiments 1 and 2, a marking portion 55 is used, and instead of the removal step ST5 shown in Figures 6 and 9, a marking step ST15 is used to apply a removal mark MK indicating the position (range) EPP of the portion to be cut and removed containing the magnetic foreign matter particles MP within the strip-shaped electrode plate FP. For example, in Figure 11, a marking area MKP (for example, a portion 1 cm inward in the width direction from the edge) is set within the exposed portion FFe1 of the strip-shaped electrode plate FP, as shown by a dashed line. A removal mark MK is applied to the area of ​​the marking area MKP that is included in the area to be removed EP. Specifically, the removal mark MK is printed on the exposed area FFe1 using an inkjet printer that forms the marking area 55.

[0103] Furthermore, the removal marks should be appropriately selected depending on the object being inspected. For example, in the case of the long strip-shaped electrode plate FP shown in Figure 11, in addition to printing the removal mark MK described above, numerous perforated punch holes can be made in the area of ​​the exposed portion FFe1 that is included in the area to be removed EP. Alternatively, tab-shaped removal marks MK can be attached to the area of ​​the exposed portion FFe1 that is included in the area to be removed EP. Figure 11 shows an example where the removal mark MK is placed on the area to be removed EP of the electrode plate FP, which is the object being inspected. However, considering the operating speed of the equipment used for removal, the mark MK may also be formed on the object being inspected (e.g., the electrode plate FP) at a mark area MKP determined from the position EPP, such as 50 cm downstream HHD from the position EPP of the area to be removed EP.

[0104] The present invention has been described above in accordance with Embodiments 1 and 2 and Modified Embodiments 1 and 2. However, it goes without saying that the present invention is not limited to the embodiments, and can be applied with appropriate modifications without departing from the spirit of the invention.

[0105] In Embodiment 1, etc., first and second timings t1 and t2 are acquired, the operation timing acquisition unit 60 predicts the operation timing t3, and at this predicted operation timing t3, the removal unit 50 removes and discharges the part to be removed EP containing magnetic foreign matter particles MP from the positive electrode paste IM. Alternatively, a removal mark MK is provided.

[0106] However, a flow meter (not shown) or the like may be provided separately, and the transport speed Vh of the positive electrode paste IM may also be obtained in the operating timing acquisition unit 60. Then, the acquired first and second timings t1 and t2 may be compared with the flow velocity obtained from the 1-2 distance L12 between the first transport position HH1 and the second transport position HH2, and the transport speed Vh of the positive electrode paste IM obtained from the flow meter or the like may be corrected, and the operating timing t3 may be predicted using the corrected transport speed Vh'.

[0107] Furthermore, in the aforementioned embodiments 1 and 2 and modified form 1, examples were shown in which the present invention is applied when a fluid such as positive electrode paste IM flows through a pipe PP. However, as explained in modified form 2 (see Figure 11), it can also be applied to a series of solid components such as a long strip-shaped electrode plate FP (e.g., a long strip-shaped separator, a long strip-shaped self-supporting electrode layer). It can also be applied when individual components having a predetermined length, such as strip-shaped electrode plates obtained by cutting a long strip-shaped electrode plate to predetermined lengths, are transported intermittently on a conveyor belt or the like. [Explanation of symbols]

[0108] PP piping HH transport direction HHU (Upstream side in the transport direction) HHD (downstream side in the transport direction) HH1 1st transport position HH2 2nd transport position HH3 3rd transport position HH4 4th transport position HH5 5th transport position CH circumferential direction CH1 1st lap position CH2 2nd lap position DH1 1st direction IM positive electrode paste (object under inspection) MP magnetic foreign particles OM (External Magnetic Field) EP part to be removed MK removal mark 10,110,111 Foreign particle removal device 1. First magnetic sensor 2. Second magnetic sensor 3. Third magnetic sensor 4. Fourth magnetic sensor 5. Magnetic sensor for verification 6. Second magnetic sensor for verification S1(t) First sensor signal S2(t) Second sensor signal S3(t) Third sensor signal S4(t) Fourth sensor signal SC(t) Confirmation sensor signal SC2(t) Second sensor signal for verification D12(t) 1-2 difference signal D13(t) 1-3 difference signal D24(t) 2-4 difference signal DC(t) Confirmation Difference Signal DD(t) Second-order difference signal TH1 First threshold TH2 Second threshold TH3 3rd threshold TH4 4th threshold t1 First Timing t2 Second timing t3 Operation timing 21 1-2 difference signal acquisition section 122 1-3 Difference signal acquisition section 123 2-4 Difference signal acquisition section 130 Second-order difference signal acquisition unit 40,140 Foreign object detection unit 41,141 First foreign object detection unit 42,142 Second foreign object detection unit 50 Removal section (processing section for the part to be removed) 55 Marking section (processing section for removal) 60 Operation timing acquisition unit 70 Verification Section 90 Magnetization part MF magnetic field ST0 Foreign Matter Magnetization Step ST1, ST1a~ST1d Sensor signal acquisition steps ST2 Differential signal acquisition step ST12a 1-3 Difference Signal Acquisition Step ST12b 2-4 Difference Signal Acquisition Step ST3, ST13 Foreign object detection step ST4 Operation timing acquisition step ST5 Removal step (processing unit operation step) ST15 Marking removal step (processing unit operation step) ST6 Verification Step ST7 Step to obtain the second-order difference

Claims

1. A foreign matter particle removal system that removes magnetically charged foreign matter particles contained in an object to be inspected that is transported from the upstream side to the downstream side in the transport direction, A first magnetic sensor is positioned at a first transport position in the transport direction and outputs a first sensor signal indicating whether or not magnetic foreign matter particles have passed through the first transport position. A second magnetic sensor is positioned at a second transport position downstream of the first transport position in the transport direction, and outputs a second sensor signal indicating whether or not magnetic foreign matter particles have passed through the second transport position. From the first sensor signal and the second sensor signal, The presence or absence of the magnetic foreign particles passing through the first transport position and the first timing at which the magnetic foreign particles pass through the first transport position are detected, The presence or absence of the magnetic foreign particles passing through the second transport position and the second timing at which the magnetic foreign particles pass through the second transport position are detected. Foreign object detection unit, A removal unit processing unit is located at a third transport position downstream of the second transport position, The part of the inspected object containing the magnetic foreign matter particles detected by the foreign matter detection unit is removed, or A removal mark indicating the location of the part to be removed is applied to the part to be removed of the object to be inspected, or to a mark area determined from the location of the part to be removed. The part to be removed and the processing unit, The system includes an operation timing acquisition unit that obtains an operation timing for operating the removal unit processing unit from the first timing and the second timing. Foreign particle removal system.

2. A foreign matter particle removal system according to claim 1, The system further includes a 1-2 difference acquisition unit that acquires a 1-2 difference signal, which is the difference between the first sensor signal and the second sensor signal. The aforementioned foreign object detection unit is From the 1-2 difference signal obtained from the first sensor signal and the second sensor signal, the presence or absence of the magnetic foreign particle passing through the first transport position and the first timing, and the presence or absence of the magnetic foreign particle passing through the second transport position and the second timing are detected. Foreign particle removal system.

3. A foreign matter particle removal system according to claim 1 or claim 2, A third magnetic sensor is positioned at the first transport position, facing the first magnetic sensor via the object to be inspected, and outputs a third sensor signal indicating the presence or absence of magnetic foreign particles contained in the object to be transported. A fourth magnetic sensor is positioned at the second transport position, facing the second magnetic sensor via the object to be inspected, and outputs a fourth sensor signal indicating the presence or absence of magnetic foreign particles contained in the object to be transported. A 1-3 difference signal acquisition unit acquires a 1-3 difference signal, which is the difference between the first sensor signal and the third sensor signal. The system further includes a 2-4 difference signal acquisition unit that acquires a 2-4 difference signal, which is the difference between the second sensor signal and the fourth sensor signal. The aforementioned foreign object detection unit is From the 1-3 difference signal and the 2-4 difference signal obtained from the first to fourth sensor signals, the presence or absence of the magnetic foreign particle passing through the first transport position and the first timing, and the presence or absence of the magnetic foreign particle passing through the second transport position and the second timing are detected. Foreign particle removal system.

4. A foreign matter particle removal system according to claim 3, The system further includes a second-order difference signal acquisition unit that acquires a second-order difference signal, which is the difference between the 1-3 difference signals and the second sensor signal. The aforementioned foreign object detection unit is From the aforementioned two-order difference signal, the presence or absence of the magnetic foreign particle passing through the first transport position and the first timing, and the presence or absence of the magnetic foreign particle passing through the second transport position and the second timing are detected. Foreign particle removal system.

5. A foreign matter particle removal system according to claim 1 or claim 2, The removal part processing unit is, This is a removal unit that removes the part to be removed from the object to be inspected. A confirmation magnetic sensor is positioned at a fourth transport position downstream of the removal unit, and outputs a confirmation sensor signal indicating whether or not magnetic foreign matter particles have passed through the fourth transport position for the inspected object from which the removal unit has been removed. The system further includes a confirmation unit that detects from the confirmation sensor signal whether or not the magnetic foreign particles have passed through the fourth transport position. Foreign particle removal system.

6. A foreign matter particle removal system according to claim 1 or claim 2, The system further includes a magnetization section at a fifth transport position upstream of the first transport position in the transport direction, which applies a magnetic field perpendicular to the transport direction and directed toward a first direction from the inspected object toward the first magnetic sensor to the inspected object, thereby magnetizing metallic foreign matter particles contained in the inspected object and converting them into magnetic foreign matter particles. Foreign particle removal system.

7. A method for removing magnetic foreign particles contained in an object to be inspected that is transported from the upstream side to the downstream side in the transport direction, A first magnetic sensor is positioned at a first transport position in the transport direction and outputs a first sensor signal indicating whether or not magnetic foreign matter particles have passed through the first transport position. A second magnetic sensor is positioned at a second transport position downstream of the first transport position in the transport direction, and outputs a second sensor signal indicating whether or not magnetic foreign matter particles have passed through the second transport position. A sensor signal acquisition step of acquiring the first sensor signal and the second sensor signal, From the acquired first sensor signal and second sensor signal, The presence or absence of the magnetic foreign particles passing through the first transport position and the first timing at which the magnetic foreign particles pass through the first transport position are detected, The presence or absence of the magnetic foreign particles passing through the second transport position and the second timing at which the magnetic foreign particles pass through the second transport position are detected. Foreign object detection step, By activating the removal unit processing unit located at the third transport position downstream of the second transport position, The part of the inspected object containing the magnetic foreign matter particles detected by the foreign matter detection unit is removed, or A removal mark indicating the location of the part to be removed is applied to the part to be removed of the object to be inspected, or to a mark area determined from the location of the part to be removed. Processing unit operation step, The system includes an operation timing acquisition step, which obtains an operation timing for operating the removal unit processing unit from the first timing and the second timing. Foreign particle removal method.

8. A method for removing foreign particles according to claim 7, The aforementioned foreign object detection step is: A 1-2 difference acquisition step is to acquire a 1-2 difference signal, which is the difference between the first sensor signal and the second sensor signal. A first foreign object detection step that detects whether or not the magnetic foreign object particles have passed through the first transport position and the first timing from the 1-2 difference signal, A second foreign object detection step that detects whether or not the magnetic foreign object particles have passed through the second transport position and the second timing from the 1-2 difference signal, and Foreign particle removal method.

9. A method for removing foreign particles according to claim 7 or claim 8, The sensor signal acquisition step is as follows: A third magnetic sensor is positioned at the first transport position, facing the first magnetic sensor via the object to be inspected, and outputs a third sensor signal indicating the presence or absence of magnetic foreign particles contained in the object to be transported. Further, a fourth magnetic sensor is positioned at the second transport position, facing the second magnetic sensor via the object to be inspected, and outputs a fourth sensor signal indicating the presence or absence of the magnetic foreign particles contained in the object to be transported. The first sensor signal to the fourth sensor signal is acquired, The aforementioned foreign object detection step is: A 1-3 difference acquisition step is to acquire a 1-3 difference signal, which is the difference between the first sensor signal and the third sensor signal. The system includes a 2-4 difference acquisition step, which acquires a 2-4 difference signal, which is the difference between the second sensor signal and the fourth sensor signal. From the 1-3 difference signal and the 2-4 difference signal, the presence or absence of the magnetic foreign particle passing through the first transport position and the first timing, and the presence or absence of the magnetic foreign particle passing through the second transport position and the second timing are detected. Foreign particle removal method.

10. A method for removing foreign particles according to claim 9, The aforementioned foreign object detection step is: The system further includes a second-order difference signal acquisition step, which acquires a second-order difference signal, which is the difference between the 1-3 difference signals and the second sensor signal. From the aforementioned two-order difference signal, the presence or absence of the magnetic foreign particle passing through the first transport position and the first timing, and the presence or absence of the magnetic foreign particle passing through the second transport position and the second timing are detected. Foreign particle removal method.

11. A method for removing foreign particles according to claim 7 or claim 8, The removal part processing unit is, This is a removal unit that removes the part to be removed from the object to be inspected. The system further includes a confirmation step of detecting whether or not the magnetic foreign particles have passed through the fourth transport position from the confirmation sensor signal of a confirmation magnetic sensor, which is located downstream of the removal unit and outputs a confirmation sensor signal indicating whether or not the magnetic foreign particles have passed through the fourth transport position for the object to be inspected from which the removal unit has been removed. Foreign particle removal method.

12. A method for removing foreign particles according to claim 7 or claim 8, The process includes a foreign matter magnetization step in which, at a fifth transport position upstream of the first transport position in the transport direction, a magnetic field is applied to the object to be inspected that is perpendicular to the transport direction and directed in a first direction toward the first magnetic sensor from the object to be inspected, thereby magnetizing the metallic foreign matter particles contained in the object to be inspected to become magnetic foreign matter particles, and delivering them to the first transport position. Foreign particle removal method.

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