Roller terminal and sheet resistance value measuring means

Abstract

A roller terminal and a sheet resistance value measuring means are provided that can improve the reliability of the measurement results of the sheet resistance value of a conductive strip being transported. [Solution] A roller terminal (100) constituting a sheet resistance measurement means (1) is equipped with a disk portion that is brought into rolling contact with a conductive band, a means for holding the disk portion, multiple sliding terminals (101) constituting means for stabilizing the current-carrying state, and a biasing means. The disk portion (102) has a central shaft portion extending from its end face, and the holder holds the central shaft portion in a rotatable state with its tip exposed. A group of electric wires (30) forming independent current paths is connected to the sliding terminals (101), and the biasing means causes the sliding terminals to slide into contact with the exposed portions of the central shaft in a distributed manner. This allows sheet resistance to be measured without measurement errors or erroneous measurements, even on conductive bands with large undulations.

Description

[Technical Field]

[0001] The present invention relates to a roller terminal suitable for measuring the surface electrical resistance (hereinafter referred to as sheet resistance) of a conductive strip formed by forming a conductive layer on the surface of a strip-shaped non-conductive core material while conveying the conductive strip, and to a sheet resistance measuring means including the roller terminal.

[0002] More specifically, the present invention relates to a roller terminal that can stably maintain electrical continuity between a roller terminal and an electric wire extending from a voltmeter or a constant current source, even when the roller terminal contacts the unevenness of the core material during transport and vibrates, thereby improving the reliability of measurements.The present invention also relates to a sheet resistance measurement device that arranges the roller terminals in the width direction of the conductive band, which intersects with the transport direction of the conductive band, and measures the sheet resistance by a four-probe measurement method. [Background technology]

[0003] The four-terminal measurement method, in which four measurement terminals are brought into contact with the object to be measured and the electrical resistance is measured continuously, is well known. In the four-terminal measurement method, first to fourth measurement terminals are arranged in order, a constant current source is connected between the first and fourth measurement terminals arranged on the outside, and a constant DC current is supplied to the object to be measured extending between the two measurement terminals.

[0004] The voltage generated between the second and third measurement terminals, which are in contact with the object to be measured at a position inside the first and fourth measurement terminals, is measured by a voltmeter, and the electrical resistance of the object to be measured is calculated from the measured voltage and the reference current. Therefore, even for a continuously transported object to be measured, such as a conductive thread having a plating layer (hereinafter referred to as plated fiber), the electrical resistance can be obtained without cutting the continuous piece. Because the electrical resistance can be measured on the plated fiber production line, the four-terminal measurement method has been used for quality control of plated fiber.

[0005] Because plated fibers are lightweight and highly flexible, they are increasingly being used as a substitute for conductive parts such as cables made of bundled metal wires. In recent years, there has also been growing demand for conductive strips with large surface areas, not only as a substitute for conductive parts but also as a means of suppressing noise caused by unwanted electromagnetic waves emitted from electrical equipment. Conductive strips are strips with a conductive layer formed on their surface by plating, metal vapor deposition, etc., and their core materials include resin films, fabrics (including nonwoven fabrics), and nets (mesh substrates).

[0006] Since plated fibers are limited to being cut lengthwise for use, four measurement terminals were arranged along the lengthwise direction (transport direction), and the measurement results showed that electrical resistance values ​​conforming to product standards were consistently obtained, confirming the absence of plating defects. On the other hand, since conductive strips are cut to any length and width for use, it is necessary to ensure that there are no plating defects not only lengthwise but also widthwise. Therefore, there is an urgent need to develop technology that can measure sheet resistance, which is electrical resistance in two dimensions, with high accuracy.

[0007] Therefore, the applicant attempted to measure the sheet resistance by arranging roller terminals in the width direction of the conductive band and bringing a single electric wire extending from a constant current source or a voltmeter into contact with the outer periphery of the central shaft of the roller terminal via a single sliding terminal (see Figure 7). However, when measurements were performed multiple times using the same test piece cut to a specified length, the sheet resistance values ​​varied from measurement to measurement, even though the test piece was the same, and it was found that the measurements obtained with this roller terminal were unreliable (see Figure 6).

[0008] In particular, conductive bands with a core made of fabric or mesh have multiple overlapping core wires that cross each other, resulting in greater undulations than a single plated fiber, and therefore greater vibrations to which the roller terminal is subjected. Because the roller terminal and the sliding contact terminal are merely in sliding contact and not fixed, they are susceptible to even slight vibrations, making the electrical conduction state unstable. The present applicant focused on this unstable electrical conduction state as a cause of variations in sheet resistance, and after extensive research, has invented the present invention.

[0009] Patent Document 1 discloses a technology for an inspection device that inspects the in-plane electrical resistance of an electrode sheet, which is a component of a fuel cell or the like. According to the technology described in this document, four electrode elements (roller terminals) are arranged in a row in the width direction, which intersects with the conveyance direction of the electrode sheet, and the sheet resistance value of the electrode sheet during conveyance is measured using a four-terminal measurement method. In addition, an electrode element elevating means is provided that simultaneously elevates and lowers the four electrode elements, and the pressure contact force can be adjusted by elevating the four electrode elements according to the detected value of the pressure contact force of the electrode elements against the electrode sheet.

[0010] However, the technology described in Patent Document 1 connects an electric wire extending from a voltmeter or constant current source to a single current collector (sliding terminal), and the current collector is pressed against the circumferential surface of the disk portion forming the electrode element by a leaf spring to form a current path. Therefore, there was a problem in that the circumferential surface of the disk portion that contacts the electrode sheet is easily worn due to sliding contact with the current collector, which makes it prone to measurement errors. As a result, even if the product quality meets the specifications, there is a possibility that it will be discarded due to measurement errors, which could reduce yield.

[0011] Furthermore, in a configuration in which one current collector is pressed against the peripheral surface of the disk, if the core material is a fabric or a mesh, the electrode element is subjected to greater vibration than in a flat electrode sheet, which makes it easier for the current flow between the current collector and the disk element to become unstable, and it was not possible to solve the problem of unreliable measured values ​​mentioned above. Also, since the configuration is limited to raising and lowering four electrode elements simultaneously, there is a possibility that the electrode elements may separate from the measurement object when the measurement object is in contact with a location of different thicknesses for each electrode element, such as the mesh, which results in poor versatility.

[0012] Patent Document 2 discloses an apparatus and method for measuring electrical resistance by the four-terminal measurement method, similar to Patent Document 1. In detail, it is said that it is possible to obtain the resistance distribution across the entire width of the sheet by providing a long measurement terminal with multiple concave and convex portions, bringing only the convex portions into contact with the sheet, and selecting convex portions at desired positions to measure the sheet resistance value while shifting it in the width direction.

[0013] However, the technology described in Patent Document 2 only discloses contacting a wire extending from a constant current source or a voltmeter with a disk-shaped convex portion. As a result, as with the technology described in Patent Document 1, when a conductive band using a core material with large undulations is measured, there is a possibility that vibrations may cause the electrical conduction state between the disk portion and the wire to become unstable, resulting in a problem of unreliable measured values.

[0014] Patent Document 3 discloses an electrical resistance measuring means developed by the present applicant for measuring the electrical resistance value of plated fiber yarn. The technology described in this document includes a metal roller that contacts the plated fiber yarn on a rotating shaft that forms a slip ring. Four metal rollers are arranged along the conveying direction of the plated fiber yarn.

[0015] A slip ring is made up of a disk and shaft that form a metal roller, a ring that is integral with the shaft, a brush that slides against the ring, a brush holder, and a housing that houses these, all arranged on the same axis.For plated fiber yarn, it is sufficient to arrange four metal rollers along the conveying direction, so even if the axial length of each measurement terminal is long, it is easy to ensure space for installing the electrical resistance measurement means.

[0016] To apply this metal roller to a conductive band, the four metal rollers must be aligned in a straight line, with their axes aligned in the width direction of the conductive band. This makes it difficult to apply this technology to products with narrow conductive band widths, limiting the number of applicable products. Therefore, the applicant set out to provide a roller terminal that can measure sheet resistance with high accuracy, even with a simpler structure than conventional slip rings. [Prior art documents] [Patent documents]

[0017] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-36767 Patent Document 2: Japanese Patent Application Laid-Open No. 2009-204369 Patent Document 3: Japanese Patent Application Laid-Open No. 2018-184625 Summary of the Invention [Problem to be solved by the invention]

[0018] The problem to be solved by this invention is to provide a roller terminal that can stabilize the electrical connection between the roller terminal and a constant current source / voltmeter, thereby improving the reliability of measured values, even when the roller terminal is subjected to vibration due to the unevenness of the core material that forms the conductive band. Also, to provide a sheet resistance measurement means that measures sheet resistance by a four-terminal measurement method by arranging four such roller terminals in a direction perpendicular to the conveyance direction of the conductive band. [Means for solving the problem]

[0019] A first aspect of the present invention is a roller terminal suitable for measuring the sheet resistance of a conductive band body having a conductive layer formed on the surface of a non-conductive core material extending in a strip-like shape, and comprising: a disk portion that is brought into rolling contact with the conductive band body; means for holding the disk portion; and means for stabilizing a current-carrying state, wherein the disk portion has a central shaft portion extending from at least one end face portion, the holding means holds the central shaft portion in a rotatable state with its tip end exposed, the stabilizing means having a plurality of sliding terminals and a plurality of biasing means, the sliding terminals being individually connected to electric wires forming independent current-carrying paths, and each of the biasing means being arranged at a desired interval around the exposed portion of the central shaft portion to bias the sliding terminals toward the central shaft portion and bring the sliding terminals into sliding contact with the outer peripheral surface of the exposed portion in a distributed manner, allowing the sheet resistance to be measured with current flowing stably between at least one of the electric wires and the central shaft portion.

[0020] The peripheral surface of the disk portion of the roller terminal is in rolling contact only with the conductive band during transport, and does not come into contact with the sliding terminal. In other words, unlike conventional technology, the peripheral surface of the disk portion does not experience wear due to sliding contact with the sliding terminal. This allows for long-term suppression of fluctuations in contact resistance between the roller terminal and the conductive band, and also allows for improved measurement accuracy by using a precious metal other than stainless steel, such as copper, which has low contact resistance.

[0021] The central shaft extending from the end face of the disk portion is held by a holding means. The central shaft may be provided on only one end face and held in a cantilevered manner by the holding means, but if central shafts are provided on both end faces and held by the holding means, the disk portion is less likely to wobble, making it easier to improve the reliability of measured sheet resistance values. In addition, the holding means holds the tip side of the central shaft in a state where it is exposed to the outside of the holding means so that it can be abutted by a sliding terminal.

[0022] The means for stabilizing the current flowing state is a plurality of sliding terminals and a plurality of biasing means. Each sliding terminal is individually connected to an electric wire forming an independent current path. More specifically, in the case of a roller terminal connected to a voltmeter, the sliding terminals are individually connected to a branched electric wire extending from either the positive or negative pole of the voltmeter, so that each sliding terminal is electrically connected to the voltmeter via an independent current path. The same applies when a roller terminal is connected to a constant current source.

[0023] The biasing means are arranged at desired intervals around the central shaft portion and bias the sliding terminals toward the exposed portion of the central shaft portion. Therefore, each sliding terminal is pressed against the central shaft portion at dispersed positions on the outer periphery of the exposed portion, and is in sliding contact with the central shaft portion. Therefore, even if vibrations are transmitted from the disk portion to the sliding terminals when the roller terminal overcomes the undulations of the conductive band, power can be supplied and electrical signals can be obtained through any normally conducting current path, so the electrical current state is maintained stably.

[0024] The sliding terminal and the biasing means may be separate or integrated. If they are integrated, a leaf spring is preferable due to its simple structure. Furthermore, distributing three or more sliding terminals at equal intervals makes it easier to improve the stability of the electrical connection. Furthermore, because the sliding terminals are in contact with the exposed part of the central shaft, the wear condition of the central shaft and the contact condition of the sliding terminals can be checked without disassembling the roller terminal, facilitating daily inspections.

[0025] According to the first aspect of the present invention, the sliding terminals are individually connected to the electric wires forming independent current paths, and the pressing means presses the sliding terminals against the central shaft to prevent them from coming off. Therefore, even if the conductive band is made of a highly undulating core material such as a woven fabric, nonwoven fabric, or mesh, the direct current supplied to the roller terminal and the electrical signal obtained from the roller are less susceptible to vibrations transmitted from the conductive band to the sliding terminal via the roller terminal. This provides an advantageous effect not found in prior art, namely, increased reliability of sheet resistance measurements.

[0026] The second invention of the present invention is a roller terminal of the first invention, characterized in that the central shaft portion comprises a short central shaft portion extending from one end face portion of the disk portion and a long central shaft portion extending from the other end face portion, and the holding means holds the central shaft portion so as to expose at least the tip end side of the long central shaft portion.

[0027] According to the second aspect of the present invention, at least the tip end of the long central shaft is held exposed from the holding means, and the sliding terminals are in contact with this exposed portion. Therefore, when placing the roller terminals at both ends and the roller terminal at the inner position next to each other in a four-terminal measurement method, by arranging them so that the surfaces with the short central shafts face each other, the roller terminals can be placed adjacent to each other in a small space, even if the sliding terminals are in contact with the central shaft rather than the peripheral surface of the disk.

[0028] Furthermore, because the holding means holds the pair of central shafts, the disk is less susceptible to vibration than if it were held in a cantilevered position, making it possible to produce a highly versatile roller terminal that can be easily applied to conductive bands with short widths, and further improving the reliability of measurement values.

[0029] The third invention of the present invention is a roller terminal of the first invention, characterized in that the roller terminal consists of a fixed portion and an advancing / retreating portion, and further includes a thickness tracking means, the fixed portion fixes the roller terminal at a desired height position, the advancing / retreating portion includes the disk portion, the holding means, and the stabilizing means, the thickness tracking means attaches the advancing / retreating portion to the fixed portion so that it can be advanced and retreated, and includes an elastic body and a resilient force adjustment means, the elastic body is interposed between the advancing / retreating portion and the fixed portion, and the resilient force adjustment means adjusts the interposition position of the elastic body along the advancing / retreating direction of the advancing / retreating portion, thereby making it possible to adjust the initial resilient force of the elastic body.

[0030] According to a third aspect of the present invention, the roller terminal comprises a fixed portion and an advancing / retracting portion, and the advancing / retracting portion is attached to the fixed portion so as to be advancing and retracting via a resilient member that serves as a thickness-adjusting member. The resilient member may be, for example, a helical spring that advances the resilient body toward the conductive band, thereby pressing the disk portion against the conductive band.

[0031] The elastic force adjusting means constituting the elastic means allows the position of the elastic body that pushes the advancing / retracting portion (the position where the reaction force is obtained) to be adjusted along the advancing / retracting direction. By moving the interposing position of the elastic body closer to the advancing / retracting portion, the elastic body is compressed and the initial elastic force is strengthened, and by moving the interposing position away from the advancing / retracting portion, the compression of the elastic body is relaxed and the initial elastic force can be weakened. The initial elastic force can be adjusted according to the undulating state of the core material of the conductive band.

[0032] As a result, even with a simple structure that does not have a means for detecting the pressure contact force between the roller terminal and the conductive terminal or a control mechanism for adjusting the pressure contact force, the individual roller terminals move forward and backward in response to changes in the thickness of the conductive band due to the undulations of the core material, making it less likely that the line contact state between the disk portion and the conductive band will change, making it less likely that measurement errors will occur.

[0033] A fourth aspect of the present invention provides a sheet resistance measurement means for measuring the sheet resistance of the conductive band while conveying the conductive band, the sheet resistance measurement means including any one of the roller terminals of the first to third aspects, a non-conductive roller arranged opposite the roller terminal with the conductive band sandwiched therebetween, a constant current source, and a voltmeter, wherein the first to fourth roller terminals are arranged in order along the width direction of the conductive band intersecting the conveying direction, and the first roller terminal is branched from one electrode of the constant current source. a second roller terminal connected to a second group of electric wires branching off from one electrode of the voltmeter; a third roller terminal connected to a third group of electric wires branching off from the other electrode of the voltmeter; and a fourth roller terminal connected to a fourth group of electric wires branching off from the other electrode of the constant current source, the electric wires constituting the electric wire groups being independent current paths and connected to the individual sliding terminals, and the sheet resistance value being measured while a stable supply of power and acquisition of an electric signal are maintained.

[0034] According to the fourth aspect of the present invention, the first through fourth roller terminals are arranged linearly along the width direction of the conductive band, and the sliding terminals of each roller terminal are individually connected to a group of branched electric wires. These groups of electric wires function as independent current paths. Therefore, even if one sliding terminal becomes dislocated from the central shaft of the roller terminal, current can be maintained from the remaining sliding terminals. This provides a highly reliable sheet resistance measurement method that does not result in a product being determined to be defective due to measurement errors or erroneous measurements, even when the desired conductive layer is formed. [Effects of the Invention]

[0035] According to the first aspect of the present invention, even when the conductive band is made of a core material with large undulations such as a woven fabric, nonwoven fabric, or mesh, DC current can be supplied with little fluctuation even through the roller terminal, and the voltage value acquired through the roller terminal is also less susceptible to vibration. This provides an advantageous effect not found in prior art, namely, increased reliability of the measured sheet resistance value. According to the second aspect of the present invention, a highly versatile roller terminal can be provided that can be easily applied to conductive bands with a short width, and the reliability of the measurement values ​​can be further improved.

[0036] According to the third aspect of the present invention, even with a simple structure that does not have a means for detecting the pressure contact force between the roller terminal and the conductive terminal or a control mechanism for adjusting the pressure contact force, the individual roller terminals move forward and backward in response to changes in the thickness of the conductive band due to the undulations of the core material, so the line contact state between the disk portion and the conductive band is less likely to change, making it less likely to cause measurement errors. According to the fourth aspect of the present invention, it is possible to provide a highly reliable sheet resistance measurement means that does not judge a product as defective due to measurement errors or erroneous measurements even when a desired conductive layer is formed. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 is a wiring diagram of a sheet resistance value measuring means (Example 1). [Figure 2] FIG. 1 is an explanatory diagram of a sheet resistance value measuring means (Example 1). [Figure 3] FIG. 2 is an explanatory side view of the roller terminal (Example 1). [Figure 4] FIG. 2 is an explanatory cross-sectional view of a roller terminal (Example 1). [Figure 5] 1 shows the results of sheet resistance measurement according to the present invention (Example 1). [Figure 6] 10 shows the results of sheet resistance measurement using a comparative sheet resistance measurement means (Comparative Example). [Figure 7] FIG. 10 is a wiring diagram of a sheet resistance value measuring means for comparison (Comparative Example). DETAILED DESCRIPTION OF THE INVENTION

[0038] The roller terminal, which constitutes the sheet resistance measurement means, is equipped with a disk portion that is brought into rolling contact with the conductive band, a means for holding the disk portion, and multiple sliding terminals and biasing means that constitute means for stabilizing the current flow. The disk portion has a central shaft portion extending from its end face, and the holder means holds the central shaft portion in a rotatable state with its tip exposed. Each sliding terminal is connected to an electric wire that forms an independent current path, and the biasing means causes the sliding terminals to slide in contact with the exposed parts of the central shaft in a distributed manner. By supplying a constant current or acquiring an electrical signal via the sliding terminals and the independent current path, sheet resistance can be measured without erroneous or error-prone measurements, even on conductive bands with large undulations. [Example]

[0039] In Example 1, a sheet resistance measurement means 1 for measuring the sheet resistance of a conductive strip using a four-terminal measurement method and a roller terminal 100 constituting the sheet resistance measurement means will be described with reference to FIGS. 1 to 7. FIG. 1 shows a wiring diagram of four roller terminals constituting the sheet resistance measurement means, a voltmeter, and a constant current source. FIG. 2 shows a front view of the sheet resistance measurement means. FIG. 3 shows an explanatory side view of the roller terminal. FIG. 4 shows an explanatory cross-sectional view of the roller terminal taken along the line AA in FIG. 3.

[0040] Figures 5 and 6 show line graphs of the test results obtained by repeatedly measuring the sheet resistance three times. Figure 5 shows the test results obtained using the sheet resistance measurement means of the present invention, and Figure 6 shows the test results obtained using a comparative sheet resistance measurement means. Figure 7 shows a wiring diagram of the comparative sheet resistance measurement means.

[0041] The sheet resistance measurement means 1 includes four roller terminals 100, a constant current source 10, a voltmeter 20, four sets of electric wires 30, and a recording terminal 40 (see FIG. 1). It also includes a non-conductive roller 210 arranged opposite the roller terminals 100 with the conductive strip 200 sandwiched between them (see FIG. 2). The four roller terminals 100 are arranged in a line in a direction intersecting the conveyance direction of the conductive strip in the order of first roller terminal 100a, second roller terminal 100b, third roller terminal 100c, and fourth roller terminal 100d from the left in the figure.

[0042] The detailed configuration of each roller terminal will be described later with reference to Figures 3 and 4. In Example 1, the roller terminals 100 are arranged in a row, but the arrangement of the roller terminals is not limited as long as measurement by the four-terminal measurement method is possible. Also, although not shown, the conductive strip 200 is fed in one direction by a feeding means. The sheet resistance value measuring means 1 is not limited to being installed midway along the conductive strip manufacturing line, but may also be installed in a quality inspection device separated from the manufacturing line.

[0043] The constant current source 10 has a first electric wire group 30a branching from one electrode and connected to the first roller terminal 100a, and a fourth electric wire group 30d branching from the other electrode and connected to the fourth roller terminal 100d (see FIG. 1). Each electric wire group 30 is made up of the same number of electric wires as the three sliding terminals 101 provided on each roller terminal 100, and each electric wire forms an independent current path that supplies a constant DC power to the first roller terminal 100a and the fourth roller terminal 100d. The DC power supplied to the first roller terminal and the fourth roller terminal is then supplied to the second roller terminal 100b and the third roller terminal 100c via the conductive band 200 (see FIG. 2).

[0044] Voltmeter 10 has second electric wire group 30b branching off from one electrode and connected to second roller terminal 100b, and third electric wire group 30c branching off from the other electrode and connected to third roller terminal 100c. These electric wire groups 30b and 30c are also made up of the same number of electric wires as slide terminals 101b and 101c (three each) provided on the roller terminals, and each electric wire forms an independent current path for acquiring an electric signal from the second roller terminal and the third roller terminal (see FIG. 1).

[0045] The recording terminal 40 communicates with the voltmeter 20 to acquire an electrical signal indicating the combined voltage value acquired by the voltmeter from the second electric wire group 30b and the third electric wire group 30c, and records the history of the change over time. Furthermore, the recording terminal 40 constantly calculates the sheet resistance value from the voltage value at each measurement and the current value of the stabilized DC power supplied from the constant current source 10. If a location where the sheet resistance value does not meet the product standard is detected, the location of the defect that does not meet the product standard is identified based on the sheet resistance value history of the conductive strip and the conductive strip feed speed, and the defect location is cut and removed, thereby preventing the shipment of a conductive strip that does not meet the product standard. The recording terminal may be a well-known general-purpose PC.

[0046] Non-conductive roller 210 is made of a shaft with a circular cross section that is wider than conductive band 200, and is disposed opposite four roller terminals 100 across conductive band 200. The shaft of the non-conductive roller is made of non-conductor 211 whose outer periphery is cylindrical, and central shaft 212 for maintaining the shape is inserted through the central hole of the non-conductor. Central shaft 212 is rotatably supported by bearings 213 that stand upright at both ends.

[0047] The material of the non-conductor 211 may be an insulating material made of resin. The non-conductive roller does not need to be rotated by a motor, but only needs to be able to rotate slowly by frictional resistance when it comes into contact with the conductive strip 200 being transported in one direction. Note that the conductive strip feed roller is not shown here because it may be provided in the plating equipment as a separate unit from the sheet resistance value measuring means 1.

[0048] Each roller terminal 100 comprises the sliding terminal 101, which also functions as a means for stabilizing the current-carrying state, a disk portion 102 that contacts the conductive band 200, and a holding means 103 that holds the disk portion (see FIGS. 3 and 4). Furthermore, the roller terminal 100 is composed of an advancing / retracting portion 110 and a fixed portion 120, and the advancing / retracting portion can be moved forward and backward by following the undulations of the conductive band using a thickness-following means 130. The advancing / retracting portion 110 includes the sliding terminal 101, the disk portion 102, and the holding means 103. The fixed portion 120 may be fixed to a suspension member 300 disposed above the conductive band 200 by a fixing means such as a screw.

[0049] First, the disk portion 102 has central shaft portions 104 extending from its left and right end faces (see Figures 3 and 4). Both central shaft portions 104 are cylindrical and have the same diameter, with a short central shaft portion 104a extending from one end face of the disk portion and a long central shaft portion 104b extending from the other end face. The disk portion 102, including the central shaft portions 104, is formed from a single piece of copper. Each central shaft portion 104 also has an annular recess 105 into which a bearing ball is fitted.

[0050] The holding means 103 is composed of a part with a roughly U-shaped cross section, which connects a pair of holding plates 106 arranged on the sides of both end faces of the disk portion. A bearing consisting of a bearing mechanism 107 is provided in the center of each holding plate 106. This bearing 107 rotatably supports the short central shaft portion 104a without exposing its tip end to the outside and without any play (see Figure 4). On the other hand, the long central shaft portion 104b is rotatably supported with its tip end exposed to the outside. Like a non-conductive roller, the disk portion 102 rotates gently due to frictional resistance when it comes into contact with a conductive band being transported in one direction.

[0051] The stabilizing means is the sliding terminal 101 made of a leaf spring, and the sliding terminal itself also functions as the biasing means (see FIG. 3). The leaf spring is formed by bending a generally L-shaped flat plate, with flat plate base 108 fixed along the outer surface of holding plate 106, and leaf spring tip 109 standing approximately perpendicular to flat plate base 108 and extending so as to contact the outer circumferential surface of central shaft 104b. Furthermore, the tip side of leaf spring tip 109 is bent so as to fit along the outer circumferential surface of central shaft 104b.

[0052] The bent tip of the leaf spring is further heat treated to give it the resilience of a leaf spring. The material of the sliding contact terminal can be iron, stainless steel, etc., but phosphor bronze (an alloy of copper, tin, and phosphorus) is preferred, as it has excellent spring properties and high electrical conductivity. Beryllium copper alloy and nickel silver (an alloy of copper, zinc, and nickel) are also suitable, as they have excellent spring properties and electrical conductivity.

[0053] Three sliding terminals 101, which also function as biasing means, are provided at equal intervals around the outer periphery of the central shaft (see FIGS. 3 and 4). Each sliding terminal is connected to an individual electric wire in the electric wire group to form an independent current path, which is connected to a constant current source or a voltmeter. There are no particular restrictions on the method for connecting the electric wires to the sliding terminal. For example, part of the sliding terminal may be bent and raised, and the electric wire may be welded or soldered to it.

[0054] Furthermore, the biasing means is not limited to forming sliding terminal 101 with a leaf spring, and may of course be separate from the sliding terminal. For example, a reaction wall may be provided facing the outer circumferential surface of central shaft portion 104b, and a resilient member may be sandwiched between the reaction wall and the central shaft portion to press the sliding terminal against the outer circumferential surface of the central shaft portion. In this case, too, the biasing means presses the sliding terminal against the central shaft portion, so that the sliding terminal will not separate from the central shaft portion not only when the sliding terminal is subjected to vibration, but also when central shaft portion 104b becomes thinner due to wear.

[0055] Even if the conductive band has large undulations and roller terminal 100 is subjected to large vibrations, a stable current flow state can be maintained as long as all of the independent current-carrying paths connected to three sliding terminals 101 do not simultaneously come off central shaft portion 104. This makes it extremely unlikely that erroneous measurements of sheet resistance will occur, resulting in a highly reliable sheet resistance measurement means.

[0056] The thickness tracking means 130 includes an elastic body 131 and a resilient force adjusting means 132 (see FIGS. 3 and 4). It also includes a pair of advancing and retreating shafts 133 (see FIGS. 3 and 4) for preventing the advancing and retreating portion 110 from pivoting along a horizontal plane relative to the fixed portion 120. When the thickness tracking means 130 brings the roller terminals 100 into contact with the conductive band to measure the sheet resistance, it is possible to move each roller terminal forward and backward in the vertical direction in accordance with the surface undulations of the conductive band.

[0057] This allows the pressure contact force to be maintained almost uniform even when roller terminal 100 comes into contact with an uneven surface, thereby suppressing changes in contact resistance. Here, elastic body 131 is made of a helical spring interposed between advancing / retreating portion 110 and fixed portion 120. Resilient force adjusting means 132 is made of bending plate 134 that can be moved vertically relative to fixed portion 120. Elastic body 101 is inserted around one of a pair of advancing / retreating shafts 133, advancing / retreating shaft 133a, located in the center, of a pair of advancing / retreating shafts 133 standing up from the top of holding means 103 (see Figure 3).

[0058] The lower end of elastic body 101 abuts against the top portion of holding means 103, and the upper end of the elastic body abuts against the lower horizontal portion of refracting plate 134 (see FIG. 4). Elastic body 101 receives a reactive force from refracting plate 134, causing advancing / retreating section 110 to move relative to fixed section 120 and pressing it against the conductive band with a desired pressure. To change the initial elastic force using elastic force adjusting means 132, the position where the reactive force is received from refracting plate 134, i.e., the interposition position of the upper end of elastic body 131, may be adjusted (see h1 in FIG. 4).

[0059] Specifically, to weaken the initial elastic force, the position of the refracting plate 134 can be shifted upward to reduce the amount of compression of the elastic body 131 (see FIG. 4(A)), and to strengthen the initial elastic force, the position of the refracting plate 134 can be shifted downward to increase the amount of compression of the elastic body 131 (see FIG. 4(B)). The shape of the refracting plate 134 is not limited, but here it is bent by approximately 90 degrees so that the upper and lower ends of the flat plate face in opposite directions.

[0060] The lower horizontal portion of the refracting plate 134 is provided with through holes 135 through which the pair of advance / retract shafts 133 are inserted (see FIG. 4), and the vertical portion of the refracting plate is provided with elongated holes 136 extending in the up-down direction (see FIG. 3). The refracting plate 134 is fixed to the side plate of the fixed part 120 using these elongated holes 136 so that its position can be changed. Specifically, female screw holes are provided in the side plate of the fixed part 120, and the female screw holes and elongated holes 136 are aligned. Male screws 137 are threaded into the female screw holes, and the both sides of the elongated holes 136 are tightened by the heads of the male screws to fix the plate.

[0061] Furthermore, a long bolt 141 constituting a means 140 for preventing the deflecting plate from shifting is abutted against the upper horizontal portion of the deflecting plate 134, preventing the deflecting plate 134 from shifting upward even after long-term use of the roller terminal 100. The long bolt is threadedly engaged with a protruding portion 121 provided on a side plate constituting the fixing portion 120 (see FIGS. 3 and 4). This protruding portion 121 is provided with a female threaded through hole 122 that penetrates in the vertical direction, and the lower end of the long bolt 141 protrudes below the protruding portion 121.

[0062] By changing the protruding length of the long bolt 141, the position of the upper horizontal portion of the bending plate 134 can be accurately changed (see h2 in Figure 4). To adjust the position of the bending plate 134, first loosen the male screws 137 that secure the bending plate 134 to the fixing portion 120 to allow the bending plate to be adjusted up and down. Next, adjust the screw length of the long bolt 141 so that the bending plates 134 of the four roller terminals 100 are secured at approximately the same height. Finally, after the upper horizontal portion of the bending plate is brought into contact with the lower end of the long bolt, tighten the male screws 137 to secure the bending plate in place. This allows the pressure contact force of the four roller terminals against the conductive band to be adjusted approximately uniformly even with a simple structure.

[0063] The pair of advancing and retreating shafts 133 are shafts that stand upright from the top of the holding means 103 (see FIG. 4). The upper side of the advancing and retreating shafts 133 is inserted into the internal space of the fixed part through a sliding hole 123 provided in the fixed part 120, and the top of the advancing and retreating shafts 133 is provided with a head 138 that is larger than the sliding hole, so that they are prevented from coming out of the sliding hole 123.

[0064] Since the advancing / retreating shaft 133 is merely inserted through the sliding hole 123, the sliding terminal 101, the disk part 102, and the holding means 103, which are integral with the advancing / retreating shaft and form the advancing / retreating part 110, are capable of advancing and retracting (moving up and down) relative to the fixed part 120. Specifically, when the disk part 102 rides up on the convex part of the conductive band, the elastic body 121 is compressed in accordance with the height of the convex part, the advancing / retreating shaft 133 is retracted (moved upward), and the entire advancing / retreating part 110 is retracted as a whole.

[0065] On the other hand, when the disk portion 102 rides over a convex portion of the conductive band, the elastic body 121 returns to its original length and the advance / retract shaft 133 advances (moves downward), mitigating the vibration transmitted to the disk portion 102 when riding over an undulation, like an automobile suspension. This also makes it possible to maintain a stable electrical connection between the roller terminal and the constant current source / voltmeter. When the conductive band has large undulations, specifically when the core material of the conductive band is made of a mesh, nonwoven fabric, fabric, etc., increasing the initial elastic force according to the undulations makes it easier to reduce the impact of vibration on measurement.

[0066] (Sheet resistance measurement test) The sheet resistance measurement test will now be described with reference to FIGS. 5 to 7. FIG. 5 shows test results according to the present invention, and FIG. 6 shows test results according to a comparative example. The graphs in FIGS. 5 and 6 show the results of three repeated measurements of the same conductive strip, superimposed on a single graph. FIG. 7 shows a schematic diagram of a comparative sheet resistance measurement device. The test specimen used in the measurement test was a conductive strip with a core made of nonwoven fabric with an average thickness of approximately 0.4 mm (400 μm), on whose surface a conductive layer with a thickness of approximately 2 μm to 20 μm was formed by electroless copper plating. The thickness of the conductive layer is easily affected by the unevenness of the nonwoven fabric, even under the same plating conditions, resulting in unevenness in the plating thickness depending on the position. As shown in the following test results, the present invention was able to measure sheet resistance more accurately and stably, even when there was unevenness in the plating thickness.

[0067] Since the conductive strip was not suitable for repeated measurements of sheet resistance at the same position in its long form, it was cut into a length of approximately 600 mm to serve as a test piece. In the measurement test, the test piece was fed by a roller at a speed of 7.0 mm per second, and the sheet resistance was measured once every 0.1 second (at approximately 0.7 mm intervals). This was repeated three times to confirm the occurrence of measurement errors in both devices.

[0068] Furthermore, after each test measurement, the feed roller is driven in the reverse direction to return the test piece to approximately the same initial position, and the test piece is accurately returned to the position without the operator touching it. Note that the graph of the measurement results shows the sheet resistance value over a length of approximately 420 mm (a total of approximately 600 measurements), with the point at which the test piece feed stabilizes being the measurement starting point (0 mm position on the graph).

[0069] Here, the configuration of a comparative sheet resistance measurement means (hereinafter referred to as a comparative device) will be briefly described with reference to Fig. 7. Comparative device 400 differs from the present invention only in the configuration of roller terminal 410. Specifically, as described above, in the present invention, each roller terminal 100 is provided with three sliding terminals 101 and an electric wire group 30 consisting of three electric wires, whereas in comparative device 400, comparative roller terminal 410 is provided with only one sliding terminal 411 and one electric wire 412.

[0070] In addition, to prevent the initial position of the test piece from shifting between measurements using the comparison device and measurements using the present invention, after the measurement test using the present invention, two sliding terminals and two electric wires are removed from each roller terminal 100, and the test is conducted using the comparison device 400.

[0071] The test results for sheet resistance are explained below. In the test results for the present invention (see FIG. 5), there were no significant errors in any of the three measurements, and the line graphs almost overlapped. In contrast, in the test results for the comparative device (see FIG. 6), the first and second measurements had relatively small variations, but in the third measurement, a large error occurred over almost the entire length of the test piece. In particular, significant errors occurred in the measurement position range from approximately 230 mm to approximately 280 mm from the measurement start point.

[0072] In particular, because there was a large error near 240 mm from the measurement start point, the measurement value at 240 mm will be specifically examined. In measurements using the comparative device, the average sheet resistance value for the first and second measurements was approximately 11.4 mΩ, while the average for the third measurement was approximately 12.2 mΩ, resulting in an error rate of approximately 8%. In measurements using the present invention, the three test results were approximately 12.7 mΩ, 12.8 mΩ, and 12.9 mΩ, resulting in an error rate of only approximately 1%.

[0073] The line graph showing the change in measured values ​​over time also shows that the measured values ​​of the present invention have less variation than the measured values ​​of the comparative test, demonstrating that the measured values ​​of the present invention are more reliable. Furthermore, the average sheet resistance over the entire length of the test piece (three measurements) measured using the comparative device also varied widely, ranging from approximately 10.6 mΩ to approximately 11.3 mΩ.

[0074] In contrast, measurements using the present invention yielded values ​​ranging from approximately 11.4 mΩ to approximately 11.5 mΩ, with almost no variation. These test results demonstrate that the roller terminal of the present invention achieves high reliability, even with a single measurement, equal to or greater than that achieved when multiple measurements are performed.

[0075] (others) For ease of understanding, this embodiment shows an example in which the second and third groups of wires are connected to one voltmeter, but it is also possible to connect each group of wires to multiple voltmeters and have the measurement values ​​of each voltmeter communicate with a recording terminal. There are no restrictions on which side the central shafts of the roller terminals should face. However, it is preferable to have the central shafts of the first and fourth roller terminals facing outward from the conductive band, and the central shafts of the second and third roller terminals facing toward the center of the conductive band, as this arrangement makes it easy to connect the wires even if the conductive band is narrow. The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The technical scope of the present invention is not limited to the above description, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0076] 1...sheet resistance value measuring means, 10... constant current source, 20... voltmeter, 30... group of electric wires, 40... recording terminal, 100... Roller terminal, 101... Sliding terminal (plate spring), 102...disk portion, 103...holding means, 104...center shaft portion, 105...annular recess portion, 106...holding plate, 107...bearing (bearing mechanism), 108...flat plate base, 109...Tip of leaf spring, 110...Advance / retreat part, 120...Fixed part, 121...protruding portion, 122...female threaded through hole, 123...sliding hole, 130... thickness following means, 131... elastic body (helical spring), 132... elastic force adjusting means, 133...advance / retract shaft, 134...refracting plate, 135...through hole, 136...long hole, 137...male screw, 138...head, 140... misalignment prevention means, 141... long bolt, 200...conductive band body, 210...non-conductive roller, 211...non-conductor, 212...central shaft body, 213...bearing portion, 300...suspension member, 400...Comparative device, 410...(comparison) roller terminal, 411...1 sliding terminal, 412...1 electric wire

Claims

1. A roller terminal suitable for measuring the sheet resistance of a conductive strip, which is made by forming a conductive layer on the surface of a non-conductive core material extending in a strip shape, a disk portion that is brought into rotational contact with the conductive band body, a means for holding the disk portion, and a means for stabilizing a current-carrying state, the disk portion has a central shaft portion extending from at least one end surface portion, the holding means holds the central shaft portion rotatably and with its tip end side exposed, the stabilizing means includes a plurality of sliding contact terminals and a plurality of biasing means; The sliding terminals are individually connected to electric wires forming independent current paths, The biasing means are arranged at desired intervals around the exposed portion of the central shaft portion to bias the sliding terminals toward the central shaft portion and bring the sliding terminals into sliding contact with the outer peripheral surface of the exposed portion in a distributed manner; measuring a sheet resistance value while stably maintaining electrical conduction between at least one of the electric wires and the central shaft portion; A roller terminal characterized by:

2. the central shaft portion comprises a short central shaft portion extending from one end surface portion of the disk portion and a long central shaft portion extending from the other end surface portion, The holding means holds the central shaft portion so that at least the tip end side of the elongated central shaft portion is exposed.

2. The roller terminal according to claim 1.

3. The roller terminal comprises a fixed portion and a retractable portion, and further includes a thickness tracking means, The fixing portion fixes the roller terminal at a desired height position, the advancing / retreating unit includes the disk unit, the holding means, and the stabilizing means; the thickness following means is provided with an elastic body and a resilient force adjusting means, and the advancing / retreating portion is attached to the fixed portion so as to be advancing / retreating; the elastic body is interposed between the advance / retreat portion and the fixed portion, The elastic force adjusting means adjusts the position of the elastic body along the advancing / retracting direction of the advancing / retracting section, thereby making it possible to adjust the initial elastic force of the elastic body.

2. The roller terminal according to claim 1.

4. a sheet resistance value measuring means for measuring the sheet resistance value of the conductive band while transporting the conductive band, a roller terminal according to any one of claims 1 to 3, a non-conductive roller arranged opposite the roller terminal with the conductive band sandwiched therebetween, a constant current source, and a voltmeter; the first to fourth roller terminals are arranged in order along a width direction of the conductive band that intersects with a conveying direction of the conductive band, a first roller terminal connected to a first group of electric wires branching off from one electrode of the constant current source; a second roller terminal connected to a second group of electric wires branching off from one electrode of the voltmeter; a third roller terminal connected to a third group of electric wires branching off from the other electrode of the voltmeter; a fourth roller terminal connected to a fourth group of electric wires branching off from the other electrode of the constant current source; The electric wires constituting the group of electric wires are made into independent current-carrying paths and connected to the individual sliding terminals, and the sheet resistance value is measured in a state where power supply and acquisition of electric signals are stably maintained. A sheet resistance value measuring means characterized by:

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