Electrolytic marking device, electrolytic marking method, and metal sheet material

Abstract

This electrolytic marking device 100 includes: a feed-out part 1; an electrolytic marking part 2 that is disposed downstream of the feed-out part 1 and marks an identification mark 60 on a metal sheet material 50; and a take-up part 3 that is disposed downstream of the electrolytic marking part 2 and takes up the metal sheet material 50 marked with the identification mark 60 in the shape of a roll.

Description

Electrolytic marking processing device, electrolytic marking processing method, and metal plate material

[0001] The present invention relates to an electrolytic marking processing device, an electrolytic marking processing method, and a metal plate, and more particularly to an electrolytic marking processing device and an electrolytic marking processing method for marking an identification mark on a metal plate, and a metal plate marked with an identification mark.

[0002] BACKGROUND ART An electrolytic marking processing apparatus for marking a metal plate is known, for example, as disclosed in Japanese Patent No. 6792379.

[0003] The above-mentioned Japanese Patent No. 6792379 discloses an electrolytic marking processing device that includes a power supply control unit, a marking head electrically connected to one electrode of the power supply control unit, a liquid retention unit that is placed on the marking head and that retains an electrolyte, a stencil that is placed on the liquid retention unit and has an area that allows the electrolyte to pass through, formed to match the shape of the marking, and a metal marking iron that is electrically connected to the other electrode of the power supply control unit.

[0004] In the electrolytic marking processing device described in the above-mentioned Japanese Patent No. 6792379, a power supply control unit supplies AC voltage to the marking head and the marking iron. Also, while the power supply control unit is supplying AC voltage to the marking head and the marking iron, the electrolytic marking process is performed on the object by manually operating the marking iron and moving the object while pressing the object against the stencil.

[0005] Patent No. 6792379

[0006] In the electrolytic marking processing device disclosed in the above-mentioned Patent Publication No. 6792379, the object (metal plate) is pressed against a stencil, and the electrolytic marking process is performed by manually operating a marking iron that electrically connects the power supply control unit and the object to move the object. This creates the problem that it is not easy to adjust the position of the object relative to the marking iron, making it difficult to perform the electrolytic marking process efficiently.

[0007] In addition, the marking processing device disclosed in the above-mentioned Japanese Patent No. 6792379 moves the object (metal plate) and positions it at a predetermined position opposite the marking head before performing electrolytic marking on the object. Therefore, in order to perform the next electrolytic marking on the object that has already undergone electrolytic marking, it is necessary to move the object so that the next object to be marked faces the marking head, and then adjust the relative position between the marking head and the object. Therefore, the electrolytic marking processing device disclosed in Japanese Patent No. 6792379 has the problem that it is not easy to perform electrolytic marking on long objects continuously and efficiently, and is not suitable for mass-producing long objects (metal plate) that have undergone electrolytic marking.

[0008] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide an electrolytic marking processing device and electrolytic marking processing method suitable for mass production that can continuously and efficiently perform electrolytic marking processing to mark identification marks on long metal plate materials, and a metal plate material marked with an identification mark.

[0009] An electrolytic marking processing device according to a first aspect of the present invention comprises an unwinding section that flattens a roll of metal plate material and sends it out, an electrolytic marking processing section that is arranged downstream of the unwinding section and marks an identification mark on the metal plate material, and a winding section that is arranged downstream of the electrolytic marking processing section and winds up the metal plate material marked with the identification mark into a roll, wherein the electrolytic marking processing section comprises a rotating shaft section that constitutes one of a pair of electrodes, and the electrolytic marking processing section surrounds the outer surface of the rotating shaft section so that one side is in contact with the rotating shaft section and the other side is in contact with the metal plate material as the metal plate material is wound around it, the electrolytic marking processing section includes a conductive roll section including an insulating member having a through hole extending from one side to the other, a storage tank in which an electrolyte is stored and in which the portion of the metal plate material wrapped around the insulating member is immersed, a counter electrode member that constitutes the other of the pair of electrodes and contacts the metal plate material, and an AC power supply section having a pair of connection terminals that are electrically connected to the conductive roll section and the counter electrode member, and the electrolytic marking processing section is configured to mark an identification mark on the metal plate material via the electrolyte supplied to the through hole by immersion using AC power supplied by the AC power supply section.

[0010] As described above, the electrolytic marking processing device according to the first aspect of the present invention includes an unwinding unit, an electrolytic marking processing unit located downstream of the unwinding unit and configured to mark an identification mark on a metal sheet, and a winding unit located downstream of the electrolytic marking processing unit and configured to wind up the metal sheet marked with the identification mark into a roll. This allows the identification mark to be marked on the metal sheet while the metal sheet is transported roll-to-roll. This allows the identification mark to be continuously and efficiently marked on the metal sheet, thereby enabling the continuous and efficient production of metal sheet materials marked with the identification mark. Furthermore, the electrolytic marking processing device is configured to mark the identification mark on the metal sheet using an electrolyte supplied to the through hole by immersing the wrapped portion of the metal sheet around the insulating member in a storage tank. As the rotating shaft rotates, the through hole (opening of the through hole) provided in the insulating member comes into contact with the metal sheet wrapped around the other side of the insulating member of the conductive roll, thereby continuously marking identification marks having shapes corresponding to the through hole (opening of the through hole) at predetermined positions on the metal sheet. Furthermore, by immersing the portion of the metal plate that wraps around the insulating member, it is possible to supply a sufficient amount of electrolyte for electrolytic marking to the through-hole of the insulating member at the portion where the metal plate wraps around, compared to when the portion of the metal plate that wraps around the insulating member is not immersed. As a result, it is possible to provide an electrolytic marking treatment device that is suitable for mass production and that can efficiently perform electrolytic marking on long metal plates.

[0011] In the electrolytic marking processing device according to the first aspect, preferably, the through holes have a shape corresponding to the identification mark, and a plurality of through holes are provided. With this configuration, the plurality of through holes having a shape corresponding to the identification mark causes the plurality of through holes (openings of the through holes) in the insulating member to continuously contact the metal plate material that wraps around the other side of the insulating member of the conductive roll portion as the rotating shaft rotates. Therefore, it is possible to mark a plurality of identification marks on the metal plate material during one rotation, and it is also possible to continuously mark a plurality of identification marks on the metal plate material through continuous rotation. As a result, it is possible to provide an electrolytic marking processing device suitable for mass production that can more efficiently perform electrolytic marking on long metal plate materials.

[0012] In the electrolytic marking processing device according to the first aspect, the counter electrode member is preferably arranged upstream or downstream of the conductive roll section and configured as a roll that rotates while in contact with the metal sheet. With this configuration, since the counter electrode member is configured as a roll, electricity can be easily passed between the rotating roll (counter electrode member) and the metal sheet by wrapping the metal sheet around the roll and rotating it, or by pressing the roll against the surface of the metal sheet and rotating it. Furthermore, the contact area between the metal sheet and the counter electrode member (roll) can be easily increased. This makes it easier to pass electricity between the metal sheet and the counter electrode member (roll). Furthermore, when the counter electrode member rotates, frictional resistance of the counter electrode member (roll) is reduced, unlike when the counter electrode member does not rotate, thereby suppressing wear of the counter electrode member (roll) and preventing scratches on the metal sheet.

[0013] A second aspect of the present invention provides a metal plate material on which an identification mark has been marked by the electrolytic marking processing device according to the first aspect. By marking the identification mark on the metal plate material, it is possible to reliably distinguish between the front and back surfaces of the metal plate material, even if the front and back surfaces have similar colors. The metal plate material may be a bimetal. Since the thermal expansion coefficient of the front surface of a bimetal differs from the thermal expansion coefficient of the back surface, by marking the identification mark on at least one surface, it is possible to reliably distinguish between the surface with a high thermal expansion coefficient and the surface with a low thermal expansion coefficient.

[0014] According to a second aspect of the present invention, there is provided a metal plate material on which an identification mark has been marked by the electrolytic marking processing device according to the first aspect and on which an oxide film has been formed. The formation of the oxide film on the metal plate material on which the identification mark has been marked improves the oxidation resistance of the surface of the metal plate material, thereby making it possible to suppress corrosion due to oxidation of the surface of the metal plate material.

[0015] An electrolytic marking method according to a third aspect of the present invention includes the steps of: supplying a metal sheet from an unwinding section to an electrolytic marking processing section; wrapping the metal sheet supplied to the electrolytic marking processing section around one side of an insulating member that surrounds the outer surface of a rotating shaft that constitutes a rotating conductive roll section and has one side in contact with the other side of the rotating shaft; immersing the wrapped portion of the metal sheet around the insulating member in an electrolyte stored in a reservoir; supplying the electrolyte to a through hole extending from one side to the other side of the insulating member; supplying AC power between the metal sheet and the rotating shaft while the wrapped portion of the metal sheet around the insulating member is immersed in the electrolyte, thereby forming and marking an identification mark on the metal sheet via the electrolyte supplied to the through hole; and winding up the metal sheet marked with the identification mark in a winding section.

[0016] As described above, the electrolytic marking method according to the third aspect of the present invention includes the steps of supplying a metal plate from an unwinding section to an electrolytic marking processing section, forming and marking an identification mark on the metal plate using an electrolyte supplied to the through hole, and winding up the metal plate marked with the identification mark in a winding section, thereby making it possible to mark the identification mark on the metal plate while transporting the metal plate in a roll-to-roll manner. This provides a method for continuously and efficiently marking an identification mark on a metal plate and continuously and efficiently producing metal plate materials marked with an identification mark. The method further includes a step of wrapping the metal sheet supplied to the electrolytic marking processing unit around the outer surface of a rotating shaft that constitutes a rotating conductive roll, contacting one side of the insulating member with the other side of the rotating shaft, and immersing the wrapped portion of the metal sheet around the insulating member in an electrolyte stored in a reservoir, thereby supplying the electrolyte to the through-holes in the insulating member. This allows the through-holes (openings of the through-holes) in the insulating member to contact the metal sheet wrapped around the other side of the insulating member of the conductive roll as the rotating shaft rotates, thereby continuously marking predetermined positions on the metal sheet with identification marks of shapes corresponding to the through-holes (openings of the through-holes). Furthermore, by immersing the insulating member, sufficient electrolyte can be supplied to the through-holes in the insulating member for electrolytic marking, compared to when the insulating member is not immersed. As a result, an electrolytic marking method suitable for mass production can be provided, which allows efficient electrolytic marking of long metal sheets.

[0017] A fourth aspect of the present invention provides a metal plate material on which an identification mark has been marked by the electrolytic marking method according to the third aspect. By marking the identification mark on the metal plate material, it is possible to reliably distinguish between the front and back surfaces of the metal plate material, even if the front and back surfaces have similar colors. The metal plate material may be a bimetal. Since the thermal expansion coefficient of the front surface of a bimetal differs from the thermal expansion coefficient of the back surface, by marking the identification mark on at least one surface, it is possible to reliably distinguish between the surface with a high thermal expansion coefficient and the surface with a low thermal expansion coefficient.

[0018] According to a fourth aspect of the present invention, there is provided a metal plate material on which an identification mark has been marked by the electrolytic marking method according to the third aspect and on which an oxide film has been formed. The formation of an oxide film on the metal plate material on which an identification mark has been marked improves the oxidation resistance of the surface of the metal plate material, thereby making it possible to suppress corrosion due to oxidation of the surface of the metal plate material.

[0019] (Additional Note) In addition to the electrolytic marking processing device of the first aspect, as a fifth aspect, the electrolytic marking processing device of the present invention may have the following configuration.

[0020] and an AC power supply unit having a pair of connection terminals electrically connected to the conductive roll unit and the counter electrode member. The electrolytic marking processing unit is configured to mark the metal plate with the identification mark using AC power supplied from the AC power supply unit. The electrolytic marking processing unit includes a conductive roll unit including a rotating shaft unit constituting one of a pair of electrodes, an insulating member surrounding the outer surface of the rotating shaft unit, in contact with the metal plate, extending from the metal plate side to the rotating shaft unit side and having a through hole filled with an electrolyte.

[0021]

[0009] Thus, by including an unwinding unit, an electrolytic marking processing unit located downstream of the unwinding unit and configured to mark an identification mark on a metal plate, and a winding unit located downstream of the electrolytic marking processing unit and configured to wind up the metal plate marked with the identification mark into a roll, it is possible to mark an identification mark on a metal plate while transporting the metal plate in a roll-to-roll manner. Therefore, it is possible to continuously mark an identification mark on a long metal plate to continuously manufacture long metal plate materials marked with an identification mark. Furthermore, the electrolytic marking processing unit includes a rotating shaft and an insulating member having a through hole extending from the metal plate side to the rotating shaft side, and is configured to mark the identification mark on the metal plate via the electrolyte inside the through hole using AC power supplied by an AC power supply. Therefore, as the rotating shaft rotates, the through hole (the opening of the through hole) of the insulating member abuts against and comes into contact with the metal plate, thereby continuously marking the identification mark on the surface of the metal plate. As a result, it is possible to provide an electrolytic marking processing apparatus suitable for mass production, which is capable of carrying out electrolytic marking processing continuously and efficiently.

[0022] Furthermore, apart from the electrolytic marking method of the third aspect, the electrolytic marking method of the sixth aspect may have the following configuration.

[0023] The electrolytic marking method of the sixth aspect includes the steps of: supplying a metal sheet from an unwinding section to an electrolytic marking processing section; bringing the metal sheet supplied to the electrolytic marking processing section into contact with an insulating member of a rotating conductive roll section, and supplying an electrolyte into a through hole provided in the insulating member that extends from the metal sheet side to the rotating shaft side; supplying AC power while the electrolyte is supplied inside the through hole at the contact portion between the metal sheet and the insulating member, thereby forming and marking an identification mark on the metal sheet via the electrolyte inside the through hole; and winding up the metal sheet marked with the identification mark in a winding section.

[0024] This method includes the steps of supplying a metal sheet from a winding section to an electrolytic marking processing section, forming and marking an identification mark on the metal sheet using an electrolyte supplied to the through hole, and winding the metal sheet marked with the identification mark in a winding section. This allows the metal sheet to be marked with an identification mark while being transported roll-to-roll. Therefore, it is possible to continuously mark a long metal sheet with an identification mark by continuously marking the long metal sheet with an identification mark. Furthermore, by including the steps of contacting the metal sheet supplied to the electrolytic marking processing section with an insulating member of a rotating conductive roll and supplying an electrolyte to a through hole in the insulating member extending from the metal sheet side to the rotating shaft side, the through hole (the opening of the through hole) of the insulating member abuts and contacts the metal sheet as the rotating shaft rotates, thereby continuously marking the identification mark on the surface of the metal sheet. This provides an electrolytic marking processing apparatus suitable for mass production, capable of efficiently performing electrolytic marking processing continuously.

[0025] According to the present invention, it is possible to provide an electrolytic marking processing device and an electrolytic marking processing method suitable for mass production that can continuously and efficiently perform electrolytic marking processing to mark identification marks on long metal plate material, and a metal plate material marked with an identification mark or a metal plate material formed with an oxide film.

[0026] Fig. 5 is a diagram showing the overall configuration of an electrolytic marking processing device according to this embodiment. Fig. 6 is a diagram showing an example of a metal plate according to this embodiment. Fig. 7 is a diagram showing an example of a metal plate marked with an identification mark according to this embodiment. Fig. 8 is a diagram showing a state in which a metal plate is wrapped around a conductive roll section according to this embodiment. Fig. 9 is a diagram for explaining an electrolytic marking processing section according to this embodiment, where (A) is an overall view and (B) is a partially enlarged view of Fig. 5(A). Fig. 10 is a diagram for explaining the principle of electrolytic marking processing.

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0028] As shown in FIG. 1 , an electrolytic marking processing device 100 according to an embodiment of the present invention is used to mark (apply) an identification mark 60 (see FIG. 3 ) on a metal sheet 50 being transported in the direction indicated by the arrow. In this embodiment, the transport direction of the metal sheet 50 in the electrolytic marking processing device 100 is represented by the X direction, with the upstream side being designated X1 and the downstream side being designated X2. The direction perpendicular to the X direction, in which the rotating shaft portion 22a of the conductive roll portion 22 (described later) extends, is referred to as the Y direction. The thickness direction of the metal sheet 50, perpendicular to the X and Y directions, is referred to as the Z direction. In this specification, the term "roll" refers to at least one of "a rotatable object" and "a wound object," and does not refer to a specific shape. Furthermore, the term "rolled" refers to a wound state, and does not refer to a specific shape.

[0029] As shown in FIG. 2 , in this embodiment, the metal plate 50 is, for example, a bimetal. The bimetal is made of two types of metal materials (or may be more than two types) with different thermal expansion coefficients, and has a high thermal expansion layer 51 made of a metal material with a high thermal expansion coefficient and a low thermal expansion layer 52 made of a metal material with a low thermal expansion coefficient. When the temperature of the bimetal increases, the high thermal expansion layer 51 expands more than the low thermal expansion layer 52, causing the bimetal to bend toward the low thermal expansion layer 52. As an example, an Mn—Cu—Ni alloy is used as the metal material on the high thermal expansion layer 51 side. As an example, an Fe—Ni alloy is used as the metal material on the low thermal expansion layer 52 side.

[0030] A device using a bimetal, such as that shown in FIG. 2, utilizes the property of the bimetal to bend as its temperature rises. Bimetals are used in electronic devices, such as thermoswitches, which are triggered to open or close when a predetermined temperature is reached. A bimetal cannot function as intended unless the high thermal expansion layer 51 and the low thermal expansion layer 52 are properly assembled. Therefore, an identification mark 60 is marked on the surface of the metal plate 50 to distinguish the high thermal expansion layer 51 and the low thermal expansion layer 52 of the bimetal to ensure proper assembly. While FIG. 3 shows an example in which the word "Proterial" is marked on the surface of the high thermal expansion layer 51 of the metal plate 50 as the identification mark 60, it may also be marked on the surface of the low thermal expansion layer 52. The identification mark 60 marked on the metal plate 50 may be any one or a combination of letters, figures, numbers, etc.

[0031] 1 , the electrolytic marking processing device 100 includes an unwinding unit 1, an electrolytic marking processing unit 2, and a winding unit 3. The electrolytic marking processing device 100 is a device that marks an identification mark 60 on a metal sheet material 50 using a roll-to-roll method while transporting the metal sheet material 50 from the unwinding unit 1 toward the winding unit 3. In detail, the electrolytic marking processing device 100 supplies the metal sheet material 50 from the unwinding unit 1 to the electrolytic marking processing unit 2, marks the identification mark 60 on the metal sheet material 50 in the electrolytic marking processing unit 2, and then winds the metal sheet material 50 into a coil in the winding unit 3.

[0032] The unwinding unit 1 is a device that continuously feeds out a rolled metal sheet material 50 (coil material) while stretching it into a flat plate. The coil material is set in the unwinding unit 1. The unwinding unit 1 has a rotation axis that extends in the Y direction.

[0033] The electrolytic marking processing unit 2 includes an AC power supply unit 21, a conductive roll unit 22, a counter electrode member 23, and a storage tank 24. The electrolytic marking processing unit 2 forms an electric circuit between the AC power supply unit 21, the conductive roll unit 22, the metal plate 50, and the counter electrode member 23, and marks an identification mark 60 on the surface of the metal plate 50 using the electrolyte 30 in the storage tank 24.

[0034] The AC power supply unit 21 has a pair of connection terminals electrically connected to the conductive roll unit 22 and the counter electrode member 23. The AC power supply unit 21 changes the direction of current, thereby switching between the anode and the cathode. Specifically, the case where the conductive roll unit 22 is the anode and the counter electrode member 23 is the cathode and the case where the conductive roll unit 22 is the cathode and the counter electrode member 23 is the anode are alternately repeated. The AC power supply unit 21 is configured to output an AC current whose voltage value, current value, frequency, etc. are controlled to predetermined values.

[0035] 4, the conductive roll unit 22 includes a rotating shaft 22a extending in the Y direction and an insulating member 22b extending along the rotating shaft 22a. The conductive roll unit 22 rotates about the Y direction as the rotating shaft 22a rotates. As the conductive roll unit 22 rotates, it marks the identification mark 60 on the metal plate 50 wrapped around the insulating member 22b while sending the metal plate 50 downstream.

[0036] In the conductive roll unit 22, the rotating shaft unit 22a constitutes one of a pair of electrodes. The rotating shaft unit 22a is electrically connected to one connection terminal of the AC power supply unit 21 via wiring. The rotating shaft unit 22a is made of a conductive material that is resistant to the electrolyte 30. As an example, the rotating shaft unit 22a is made of stainless steel. The rotating shaft unit 22a serves as the rotation axis of the conductive roll unit 22, which rotates around the Y direction.

[0037] In the conductive roll portion 22, the insulating member 22b surrounds the outer surface of the rotating shaft portion 22a with one side (inner side). The insulating member 22b contacts the metal plate 50 with the other side (outer side). The metal plate 50 is wrapped around the other side (outer side) of the insulating member 22b. The insulating member 22b is made of an insulating material that is resistant to the electrolyte 30. As an example, the insulating member 22b is made of an insulating resin-based material.

[0038] The insulating member 22b also includes a through hole 22c. The through hole 22c penetrates the insulating member 22b from one side (inner side) to the other side (outer side) and has openings that open to the one side (inner side) and the other side (outer side) of the insulating member 22b. The through hole 22c has a shape corresponding to the identification mark 60. Specifically, the opening of the through hole 22c that opens to the other side of the insulating member 22b has a shape corresponding to the identification mark 60. The shape of the opening of the through hole 22c may be any shape that corresponds to the identification mark 60, and may be, for example, a symbol or a letter. A plurality of through holes 22c are provided in the insulating member 22b. The electrolytic solution 30 is supplied to the through holes 22c of the insulating member 22b. As a result, in the conductive roll portion 22, the metal plate 50 and the rotating shaft portion 22a, which is electrically connected to the AC power supply portion 21, can be electrically connected via the electrolytic solution 30 in the through holes 22c. On the other hand, the metal plate material 50 is wrapped around and in contact with the counter electrode member 23, which is electrically connected to the AC power supply unit 21. Therefore, the counter electrode member 23 can electrically connect the metal plate material 50 and the counter electrode member 23, which is electrically connected to the AC power supply unit 21, via the wrapped portion. Therefore, with the above configuration, an AC current output from the AC power supply unit 21 flows through the metal plate material 50 with which the through hole 22c (opening) abuts, and the identification mark 60 is marked on the surface of the metal plate material 50.

[0039] The counter electrode member 23 constitutes the other electrode of the pair of electrodes. The counter electrode member 23 is electrically connected to the other connection terminal of the AC power supply unit 21 via a wire. The counter electrode member 23 is disposed either upstream (X1 side) or downstream (X2 side) of the conductive roll unit 22. In the embodiment, the counter electrode member 23 is configured as a rotating roll and is disposed upstream (X1 side) of the conductive roll unit 22. The counter electrode member 23 is not limited to the roll, and may be configured to include, for example, a contact portion that contacts the metal plate material 50. The counter electrode member 23 comes into contact with the metal plate material 50 by, for example, the metal plate material 50 being wrapped around the counter electrode member 23.

[0040] As shown in FIG. 1 , the storage tank 24 stores the electrolyte 30. The portion of the metal sheet 50 wound around the insulating member 22b is immersed in the storage tank 24. The storage tank 24 is disposed below the conductive roll portion 22. The electrolyte 30 in the storage tank 24 can be circulated using a pump or the like. The electrolyte 30 is a solution containing an ionic substance (conductive salt) at an appropriate concentration suitable for the metal sheet 50 to be subjected to the electrolytic marking process. The ionic substance (conductive salt) is a substance that dissociates into positive ions and negative ions when dissolved in a polar solvent such as water. The electrolyte 30 is a solution that exhibits the property that, when a current flows, positive ions migrate to the cathode and negative ions migrate to the anode. Note that the counter electrode member 23 is not immersed in the storage tank 24.

[0041] 1, the winding unit 3 is disposed downstream of the electrolytic marking processing unit 2. The winding unit 3 winds up the flat metal sheet material 50 marked with the identification mark 60 into a roll of metal sheet material 50. The winding unit 3 has a rotation axis extending in the Y direction.

[0042] The electrolytic marking processing device 100 further includes a cleaning section 4 , a drying section 5 , a liquid draining section 6 , deflector rolls 7 ( 7 a , 7 b , 7 c , 7 d ), and an application section 8 .

[0043] The cleaning unit 4 is disposed downstream of the conductive roll unit 22. The cleaning unit 4 cleans the metal plate material 50 marked with the identification mark 60. The cleaning unit 4 cleans the metal plate material 50 with a cleaning liquid. The cleaning unit 4 cleans the metal plate material 50 by, for example, immersing the metal plate material 50 in a cleaning liquid in a cleaning tank, pouring a cleaning liquid onto the metal plate material 50, wiping the metal plate material 50 with a brush or wiper, or combining the above methods as necessary. The cleaning unit 4 uses the above methods to wash away the electrolyte 30 and dust on the metal plate material 50.

[0044] The drying unit 5 is disposed downstream (X2 side) of the cleaning unit 4. The drying unit 5 dries the metal plate material 50 cleaned in the cleaning unit 4. The drying unit 5 dries the metal plate material 50 by, for example, blowing hot air onto the metal plate material 50 to evaporate the cleaning liquid adhering to the metal plate material 50, by contacting a water-absorbing roller with the metal plate material 50 to absorb the cleaning liquid adhering to the metal plate material 50, or by combining the above methods as necessary. The metal plate material 50 is dried by the drying unit 5 using the above methods.

[0045] The drainer unit 6 is disposed downstream (X2 side) of the conductive roll unit 22 or upstream (X1 side) of the cleaning unit 4. The drainer unit 6 removes excess electrolyte 30 and dust from the metal plate material 50 marked with the identification mark 60. The drainer unit 6 includes, for example, a brush or a wiper. The drainer unit 6 removes most of the electrolyte 30 and dust from the metal plate material 50.

[0046] As shown in FIG. 1 , in the electrolytic marking processing device 100, deflector rolls 7 are arranged on the upstream side (X1 side) and downstream side (X2 side) as needed. The deflector rolls 7 adjust the wrapping amount (wrapping angle) of the metal sheet 50 to change the angle (conveyance angle) of the metal sheet 50 with respect to the conveyance direction (X direction). Specifically, the electrolytic marking processing device 100 includes four deflector rolls 7 (7a, 7b, 7c, 7d). The first deflector roll 7a is arranged downstream (X2 side) of the unwinding section 1 and changes the conveyance angle of the metal sheet 50 sent out from the unwinding section 1. The second deflector roll 7b is arranged upstream (X1 side) of the conductive roll section 22 and changes the conveyance angle of the metal sheet 50 so that the metal sheet 50, whose conveyance angle has been changed by the first deflector roll 7a, is immersed in the electrolyte 30 in the storage tank 24. The third deflector roll 7c is disposed downstream (X2 side) of the conductive roll unit 22, and changes the conveying angle of the metal sheet material 50 in order to lift the metal sheet material 50 marked with the identification mark 60 from the electrolyte 30. The fourth deflector roll 7d changes the conveying angle of the metal sheet material 50 in order to wind up the metal sheet material 50, the conveying angle of which has been changed by the third deflector roll 7c, by the winding unit 3.

[0047] The coating unit 8 is disposed downstream (X2 side) of the drying unit 5 or upstream (X1 side) of the winding unit 3. The coating unit 8 coats, for example, a rust inhibitor or a transparent polymer onto the metal plate material 50 dried by the drying unit 5. An example of the rust inhibitor is rust-preventive oil. An example of the transparent polymer is liquid silicone rubber (LSR). The coating unit 8 may be configured to include any one of felt, sponge, and nonwoven fabric.

[0048] As shown in FIG. 5A, in the electrolytic marking process, by using the electrolyte 30, an electric circuit is formed in which a current flows between one connection terminal of the AC power supply unit 21, the rotating shaft 22a, the electrolyte 30 inside the through hole 22c (see FIG. 5B), the metal plate 50, the counter electrode member 23, and the other connection terminal of the AC power supply unit 21. Also, as shown in FIG. 5B, by immersing the metal plate 50 in the electrolyte 30 in the storage tank 24, the electrolyte 30 is supplied to the inside of the through hole 22c of the insulating member 22b located between the rotating shaft 22a and the metal plate 50. Specifically, as shown by the dashed arrow in FIG. 5A, the electrolyte 30 is supplied to the through hole 22c from a gap between the insulating member 22b and the metal plate 50 formed upstream (X1 side) of the portion where the metal plate 50 is wrapped around the insulating member 22b. The supplied electrolyte 30 enters the through-hole 22c and fills the interior of the through-hole 22c. Then, as an AC current flows and the electrolytic marking process is performed, a deposit 40 gradually deposits and builds up on the surface of the metal plate 50, and the deposit 40 becomes the identification mark 60. Note that, for convenience, in FIG. 5 , the metal plate 50 passing through the electrolyte 30 in the storage tank 24 (shown in cross section) due to the rotation of the conductive roll unit 22 is not wrapped around the insulating member 22b. However, in reality, the metal plate 50 forms a wrapped portion around the insulating member 22b (see FIG. 4 ). Also, for convenience, in FIG. 5 , the electrolyte 30 in the through-hole 22c is not in contact with the rotating shaft 22a. However, in reality, the electrolyte 30 contacts the rotating shaft 22a (the electrolyte 30 is supplied to fill the entire interior of the through-hole 22c).

[0049] The principle of the electrolytic marking process will now be described with reference to FIG. 6 . When an electric current (alternating current) flows from the metal plate 50 toward the rotating shaft 22a of the conductive roll portion 22, the state shown in FIG. 6A is reached. In this state, the metal plate 50 serves as the anode, and the rotating shaft 22a of the conductive roll portion 22 serves as the cathode. At this time, specific atoms (metal atoms such as Ni) contained in the metal plate 50 are ionized on the surface of the metal plate 50 and eluted into the electrolyte 30. In FIG. 6A , the specific atoms (ions) eluted into the electrolyte 30 are indicated by white circles.

[0050] As shown in Fig. 6B, specific atoms (ions) dissolved from the metal plate 50 into the electrolyte 30 bond with ionic substances dissociated in the electrolyte 30 to form products. The products are metal oxides containing, for example, Fe, Ni, Cr, etc. In Fig. 6B, the products are represented by black circles.

[0051] When the polarity of the current (AC) is reversed and the current (AC) flows from the rotating shaft 22a of the conductive roll portion 22 toward the metal plate 50, the state shown in FIG. 6C is reached. In this state, the metal plate 50 becomes the cathode, and the rotating shaft 22a of the conductive roll portion 22 becomes the anode. At this time, a product in the electrolytic solution 30 precipitates and adheres to the surface of the metal plate 50. The product precipitated and adhered to the surface of the metal plate 50 is colored, and can be recognized as a colored identification mark 60. The product precipitated and adhered to the surface of the metal plate 50 is called a precipitate 40. The precipitate 40 is a metal oxide, etc. For example, if the metal plate 50 is made of a Ni alloy, the precipitate 40 is a Ni-based oxide. Therefore, the black identification mark 60 is a color specific to the Ni-based oxide that constitutes the precipitate 40. The color of the identification mark 60 can be selected by selecting the electrolyte 30 containing an ionic substance according to the composition (metal element to be dissolved) of the metal plate 50. Furthermore, by adhering the precipitate 40 more thickly, the identification mark 60 can be formed in a darker color.

[0052] In this embodiment, the insulating member 22b is disposed between the rotating shaft portion 22a and the metal plate 50, so that the rotating shaft portion 22a and the metal plate 50 are not in direct contact with each other. Therefore, when current (AC) is supplied from the AC power supply unit 21, the current (AC) flows between the rotating shaft portion 22a and the metal plate 50 via the electrolytic solution 30 supplied to the through-hole 22c of the insulating member 22b, but the current (AC) does not flow in positions other than the through-hole 22c of the insulating member 22b where the electrolytic solution 30 is not supplied. Therefore, the current (AC) flows only through the portion of the rotating shaft portion 22a and the portion of the metal plate 50 that are in contact with the electrolytic solution 30 supplied to the through-hole 22c of the insulating member 22b.

[0053] When the rotating shaft 22a of the conductive roll portion 22 becomes the cathode and the metal plate 50 becomes the anode, as shown in FIG. 6A, current flows from the metal plate 50 to the rotating shaft 22a of the conductive roll portion 22. As a result, specific atoms (ions) are dissolved from the metal plate 50 into the electrolyte 30 inside the through-holes 22c. The specific atoms (ions) dissolved from the metal plate 50 into the electrolyte 30 then bond with ionic substances dissociated in the electrolyte 30 to form a product. When the polarity of the current (AC) is reversed, the rotating shaft 22a of the conductive roll portion 22 becomes the anode and the metal plate 50 becomes the cathode, as shown in FIG. 6C, the product in the electrolyte 30 precipitates and adheres as a precipitate 40 to the surface of the metal plate 50 sealing the through-holes 22c (openings). That is, the precipitate 40 adheres to the surface of the metal plate 50 in accordance with the shape of the through-holes 22c (openings). Therefore, by forming the through-hole 22c (opening) in a desired shape, it is possible to mark the metal plate 50 with an identification mark 60 in a desired shape.

[0054] (Electrolytic Marking Treatment Method) The electrolytic marking treatment method will be described with reference to FIG. The electrolytic marking processing method includes the steps of: supplying a metal sheet material (50) from an unwinding unit (1) to an electrolytic marking processing unit (2); wrapping the metal sheet material (50) supplied to the electrolytic marking processing unit (2) around an insulating member (22b) that surrounds the outer surface of a rotating conductive roll unit (22) and has one side in contact with a rotating shaft (22a) of the rolling roll unit (22); immersing the wrapped portion of the metal sheet material (50) around the insulating member (22b) in an electrolyte (30) stored in a storage tank (24); and supplying the electrolyte (30) to through holes (22c) extending from one side to the other side of the insulating member (22b); supplying AC power between the metal sheet material (50) and the rotating shaft (22a) in a state in which the wrapped portion of the metal sheet material (50) around the insulating member (22b) is immersed in the electrolyte (30), thereby forming and marking an identification mark (60) on the metal sheet material (50) via the electrolyte (30) supplied to the through holes (22c); and winding up the metal sheet material (50) marked with the identification mark (60) in a winding unit (3).

[0055] The process of supplying the metal sheet material 50 from the unwinding section 1 to the electrolytic marking processing section 2 is a process of continuously feeding out the rolled metal sheet material 50 (coil material) attached to the unwinding section 1 while stretching it into a flat plate. The continuously fed metal sheet material 50 has its conveying angle adjusted by the first deflector roll 7a, and is then supplied to the electrolytic marking processing section 2.

[0056] The metal sheet material 50 supplied to the electrolytic marking processing unit 2 is wound around and brought into contact with the other side of an insulating member 22b that surrounds the outer surface of a rotating shaft portion 22a constituting the rotating conductive roll portion 22 and has one side in contact with the rotating shaft portion 22a, and the wound portion of the metal sheet material 50 around the insulating member 22b is immersed in an electrolyte 30 stored in a storage tank 24, and the electrolyte 30 is supplied to a through hole 22c extending from one side to the other side provided in the insulating member 22b. In this process, the metal sheet material 50 supplied to the electrolytic marking processing unit 2 first comes into contact with the counter electrode member 23 (roll), and after the conveying angle is changed by a second deflector roll 7b arranged on the upstream side (X1 side) of the conductive roll portion 22, it comes into contact with the insulating member 22b of the conductive roll portion 22. At this time, the metal plate material 50 is wound around and comes into contact with one side of the insulating member 22b, one side of which is in contact with the rotating shaft portion 22a and surrounds the outer surface of the rotating shaft portion 22a constituting the rotating conductive roll unit 22. The counter electrode member 23 (roll) may be disposed downstream (X2 side) of the second deflector roll 7b. In this case, the metal plate material 50 comes into contact with the second deflector roll 7b before coming into contact with the counter electrode member 23 (roll).

[0057] When the metal plate 50 is wound around and contacts one side of the insulating member 22b, one side of which is in contact with the rotating shaft 22a and surrounds the outer surface of the rotating shaft 22a constituting the rotating conductive roll unit 22, the other side of the insulating member 22b is immersed in the electrolyte 30 stored in the storage tank 24. The electrolyte 30 in the storage tank 24 is then supplied into the through hole 22c of the insulating member 22b located between the metal plate 50 and the rotating shaft 22a. Specifically, the electrolyte 30 is supplied from a gap between the insulating member 22b and the metal plate 50, which is formed upstream (X1 side) of the winding portion of the metal plate 50 around the insulating member 22b. The supplied electrolyte 30 enters the through hole 22c and fills the interior of the through hole 22c. Immediately thereafter, the through-hole 22c (opening) is sealed (blocked) by the wrapped portion of the metal plate 50, causing the through-hole 22c to be filled with the electrolyte 30. At this time, the inside of the through-hole 22c present within the range of the wrapped portion of the metal plate 50 around the insulating member 22b is filled with the electrolyte 30. The wrapped portion of the metal plate 50 can be expressed as the product (wrapped area) of the length of the metal plate 50 wrapped around the insulating member 22b in the conveyance direction (X direction) and the length of the metal plate 50 in the width direction (Y direction). Therefore, the inside of the through-hole 22c present within the wrapped area is filled with the electrolyte 30.

[0058] In the process of forming and marking the identification mark 60 on the metal plate 50 via the electrolyte 30 supplied to the through hole 22c by supplying AC power between the metal plate 50 and the rotating shaft 22a while the portion of the metal plate 50 wrapped around the insulating member 22b is immersed in the electrolyte 30, first, current (AC) is supplied from the AC power supply 21 while the portion of the metal plate 50 wrapped around the insulating member 22b is immersed in the electrolyte 30. This forms an electric circuit through which current flows among one connection terminal of the AC power supply 21, the rotating shaft 22a, the electrolyte 30 inside the through hole 22c (see FIG. 5B ), the metal plate 50, the counter electrode member 23, and the other connection terminal of the AC power supply 21. An electric current (alternating current) flows to form an electric circuit. When the current flows such that the rotating shaft portion 22a serves as the cathode and the metal plate material 50 serves as the anode, specific atoms (ions) of the metal plate material 50 dissolve into the electrolyte 30, and ionic substances dissociate in the electrolyte 30. When the current flows in the opposite direction, such that the rotating shaft portion 22a serves as the anode and the metal plate material 50 serves as the cathode, the specific atoms (ions) of the metal plate material 50 that have dissolved into the electrolyte 30 and the ionic substances that have dissociated from the electrolyte 30 precipitate as products (e.g., oxides). The products form precipitates 40 and adhere to the metal plate material 50. The precipitates 40 (products) are metal oxides containing, for example, Fe, Ni, Cr, etc. When the precipitates 40 adhere thickly to the metal plate material 50, they become visible, and an identification mark 60 is formed (marked) on the metal plate material 50.

[0059] The formation (marking) of the identification mark 60 is performed from immediately after the specific portion of the metal plate 50 to be marked comes into contact with the insulating member 22b to form a wound portion (winding start) until the specific portion of the metal plate 50 is transported downstream (toward X2) by the rotation of the conductive roll unit 22, and immediately before the specific portion of the metal plate 50 and the insulating member 22b separate and the wound portion is released (winding end). Note that the time (reaction time) during which the identification mark 60 is actually formed (marked) by the adhesion of the precipitate 40 from the start of winding the metal plate 50 around the insulating member 22b to the end of winding is the time while the specific portion of the metal plate 50 and the opening of the through hole 22c of the insulating member 22b are maintained in a sealed state, which is, for example, 0.5 seconds. Furthermore, by increasing the length of the wrapped portion of the metal plate 50 around the insulating member 22b, i.e., the length from the upstream (X1 side) end of the wrapped portion to the downstream (X2 side) end of the wrapped portion, it is possible to ensure a longer energization time for each through-hole 22c. Furthermore, since the identification mark 60 is formed by the deposit 40 that gradually accumulates and adheres to the metal plate 50, the amount (thickness) of the deposit 40 increases as the energization time increases, allowing the identification mark 60 to become thicker.

[0060] Next, before the process of winding the metal plate material 50 marked with the identification mark 60 in the winding unit 3, the conveying angle of the metal plate material 50 is changed by the third deflector roll 7c, and then excess electrolyte 30 is drained off in the draining unit 6. After the electrolyte 30 is drained off, the metal plate material 50 is washed in the washing unit 4 and dried in the drying unit 5. The metal plate material 50 dried in the drying unit 5 is coated with a rust inhibitor or the like as needed in the coating unit 8, and then the conveying angle is changed by the fourth deflector roll 7d and supplied to the winding unit 3. Then, the process of winding the metal plate material 50 marked with the identification mark 60 in the winding unit 3 is performed. In detail, the winding unit 3 winds the flat metal plate material 50 into a roll to form a coil material.

[0061] <Effects of this embodiment> In this embodiment, the following effects can be obtained.

[0062] As described above, this embodiment includes the unwinding section 1, the electrolytic marking processing section 2 that is arranged downstream (X2 side) of the unwinding section 1 and that marks the metal plate material 50 with the identification mark 60, and the winding section 3 that is arranged downstream (X2 side) of the electrolytic marking processing section 2 and that winds up the metal plate material 50 marked with the identification mark 60 in a roll, thereby making it possible to mark the metal plate material 50 with the identification mark 60 while transporting the metal plate material 50 in a roll-to-roll manner. This makes it possible to continuously and efficiently mark the metal plate material 50 with the identification mark 60, and to continuously and efficiently produce metal plate materials 50 marked with the identification mark 60. Furthermore, the electrolytic marking device 100 is configured to mark the identification mark 60 on the metal plate 50 via the electrolyte 30 supplied to the through hole 22c by immersing the wrapped portion of the metal plate 50 around the insulating member 22b in the storage tank 24. Therefore, as the rotating shaft 22a rotates, the through hole 22c (opening of the through hole 22c) provided in the insulating member 22b contacts the metal plate 50 wrapped around the other side of the insulating member 22b of the conductive roll portion 22, thereby continuously marking the identification mark 60 at predetermined positions on the metal plate 50 with a shape corresponding to the through hole 22c (opening of the through hole 22c). Furthermore, by immersing the insulating member 22b, the through hole 22c of the insulating member 22b can be supplied with sufficient electrolyte 30 for the electrolytic marking process compared to when the insulating member 22b is not immersed. As a result, an electrolytic marking processing apparatus 100 suitable for mass production can be provided, which can efficiently perform electrolytic marking on long metal plates 50.

[0063] Furthermore, in this embodiment, the through holes 22c have a shape corresponding to the identification mark 60, and a plurality of the through holes 22c are provided. As a result, with a plurality of through holes 22c having a shape corresponding to the identification mark 60, the plurality of through holes 22c (openings of the through holes 22c) in the insulating member 22b are continuously brought into contact with the metal plate material 50 that is wrapped around the other side of the insulating member 22b of the conductive roll portion 22 as the rotating shaft portion 22a rotates. Therefore, a plurality of identification marks 60 can be marked on the metal plate material 50 during one rotation, and a plurality of identification marks 60 can be continuously marked on the metal plate material 50 by continuous rotation. As a result, it is possible to provide an electrolytic marking processing apparatus 100 that is suitable for mass production and that can more efficiently perform electrolytic marking on long metal plate materials 50.

[0064] Furthermore, in this embodiment, the counter electrode member 23 is arranged on the upstream side or downstream side of the conductive roll section 22 and is configured as a roll that rotates while in contact with the metal plate material 50. This allows the metal plate material 50 to be wound around the roll, thereby increasing the contact area between the counter electrode member 23 (roll) and the metal plate material 50. This makes it easier to pass electricity from the counter electrode member 23 (roll) to the metal plate material 50. Furthermore, because the counter electrode member 23 is configured as a roll that rotates while in contact with the metal plate material 50, frictional resistance of the counter electrode member 23 (roll) is reduced, unlike when the counter electrode member 23 does not rotate, and therefore scratches on the metal plate material 50 can be suppressed.

[0065] In this embodiment, the metal plate 50 is a metal plate 50 on which an identification mark 60 has been marked by the electrolytic marking processing device 100. By marking the identification mark 60 on the metal plate 50, it is possible to reliably distinguish between the front and back surfaces of the metal plate 50, even if the front and back surfaces have similar colors. The metal plate 50 may be a bimetal. Since the thermal expansion coefficient of the front surface of a bimetal is different from the thermal expansion coefficient of the back surface, by marking the identification mark 60 on at least one surface, it is possible to reliably distinguish between the surface with a high thermal expansion coefficient and the surface with a low thermal expansion coefficient.

[0066] Furthermore, in this embodiment, the process includes a step of supplying the metal plate material 50 from the unwinding unit 1 to the electrolytic marking processing unit 2, a step of forming and marking the identification mark 60 on the metal plate material 50 via the electrolyte 30 supplied to the through hole 22c, and a step of winding up the metal plate material 50 marked with the identification mark 60 in the winding unit 3, so that the identification mark 60 can be marked on the metal plate material 50 while the metal plate material 50 is transported roll-to-roll. This makes it possible to provide a method for continuously and efficiently marking the identification mark 60 on the metal plate material 50 and continuously and efficiently producing metal plate materials 50 marked with the identification mark 60. In addition, the method includes a step of wrapping the metal sheet material 50 supplied to the electrolytic marking processing unit 2 around the outer surface of the rotating shaft 22a constituting the rotating conductive roll unit 22 and contacting one side of the insulating member 22b with the other side of the insulating member 22b, and immersing the wrapped portion of the metal sheet material 50 around the insulating member 22b in the electrolyte 30 stored in the storage tank 24, and supplying the electrolyte 30 to the through holes 22c provided in the insulating member 22b.As the rotating shaft 22a rotates, the through holes 22c (openings of the through holes 22c) provided in the insulating member 22b come into contact with the metal sheet material 50 wrapped around the other side of the insulating member 22b of the conductive roll unit 22, and it is possible to continuously mark the metal sheet material 50 at predetermined positions with identification marks 60 having shapes corresponding to the through holes 22c (openings of the through holes 22c). Furthermore, by immersing the insulating member 22 b, it is possible to supply a sufficient amount of electrolyte 30 for the electrolytic marking process to the through holes 22 c of the insulating member 22 b compared to when the insulating member 22 b is not immersed. As a result, it is possible to provide an electrolytic marking process method suitable for mass production, which can efficiently perform electrolytic marking process on long metal plates 50.

[0067] In this embodiment, as described above, the metal plate 50 is marked with an identification mark 60 by the electrolytic marking method. By marking the identification mark 60 on the metal plate 50, it is possible to reliably distinguish between the front and back surfaces of the metal plate 50, even if the front and back surfaces have similar colors. Furthermore, the metal plate 50 may be a bimetal. Since the thermal expansion coefficient of the front surface is different from the thermal expansion coefficient of the back surface of a bimetal, by marking the identification mark 60 on at least one surface, it is possible to reliably distinguish between the surface with a large thermal expansion coefficient and the surface with a small thermal expansion coefficient.

[0068] [Modifications] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, not by the description of the above-mentioned embodiments and examples, and further includes all modifications (modifications) within the meaning and scope equivalent to the claims.

[0069] For example, in the present embodiment, an example in which the metal plate material is a bimetal has been described, but the present invention is not limited to this. In the present invention, for example, the metal plate material may be made of a single type of metal, may be a metal plate material with a two-layer structure that is not a bimetal, or may have a layer structure of three or more layers. Furthermore, when the metal plate material has a multilayer structure, it may be a rolled material (clad material), or may be a laminated material laminated by a method other than rolling, such as plating or vapor deposition.

[0070] In addition, although the rotating shaft portion is made of stainless steel in the present embodiment, the present invention is not limited to this, and the rotating shaft portion may be made of a titanium alloy.

[0071] In addition, although the present embodiment has been described with reference to an example in which a plurality of through holes are provided in the insulating member, the present invention is not limited to this. In the present invention, the insulating member may be provided with one through hole.

[0072] In addition, although the present embodiment illustrates an example in which the insulating member is made of a resin-based material, the present invention is not limited to this. In the present invention, the insulating member is made of a resin-based material containing rubber, for example. Rubber-based insulating resin-based materials include butyl rubber, which has excellent electrical insulation properties, fluorine-based rubber, which has excellent solvent resistance and heat resistance, and silicone rubber, which has excellent heat resistance. Resins other than rubber that may be used to form the insulating member include tetrafluoroethylene-based resins, polyethylene terephthalate-based resins, polycarbonate-based resins, polypropylene-based resins, and the like, which have excellent chemical resistance, electrical insulation properties, and abrasion resistance.

[0073] In addition, although the counter electrode member is formed of a roll in this embodiment, the present invention is not limited to this. In the present invention, the counter electrode member may be formed of something other than a roll, such as a plate-like member.

[0074] In addition, although the present embodiment has shown an example in which the counter electrode member and the deflector roll are configured separately, the present invention is not limited to this. In the present invention, the counter electrode member may be configured as a deflector roll. In this case, the deflector roll serving as the counter electrode member is disposed either upstream or downstream of the conductive roll portion, and, for example, either the second deflector roll or the third deflector roll can also serve as the counter electrode member.

[0075] In addition, although the present embodiment shows an example in which the deflector rolls are provided at four locations, the present invention is not limited to this. In the present invention, the deflector rolls may be provided upstream and downstream of the conductive roll portion to form the wrapping portion of the metal sheet material, and may not be provided at other locations. In addition, in the present invention, the number of locations in which the deflector rolls are provided may be any of two, three, four, and five or more.

[0076] In the present embodiment, an example has been shown in which the electrolytic marking processing device includes a cleaning unit, a draining unit, a drying unit, and an application unit, but the present invention is not limited to this. In the present invention, the electrolytic marking processing device does not have to be provided with a cleaning unit, a draining unit, a drying unit, and an application unit, and may be provided with one or more of the cleaning unit, the draining unit, the drying unit, and the application unit.

[0077] In the present embodiment, an example has been shown in which the cleaning unit immerses the metal plate material in the cleaning tank to clean it, but the present invention is not limited to this. In the present invention, the cleaning unit may clean the metal plate material by spraying a cleaning liquid or by pouring a cleaning liquid over the metal plate material.

[0078] In the present embodiment, an example is shown in which the drying unit dries the metal plate by blowing hot air onto it, but the present invention is not limited to this. In the present invention, the drying unit may dry the metal plate by blowing cold air onto it, or may dry the metal plate by irradiating it with infrared rays.

[0079] In the present embodiment, an example in which the liquid drainer includes a wiper has been described, but the present invention is not limited to this. In the present invention, the liquid drainer may include a doctor blade or a roller instead of a wiper. Furthermore, the liquid drainer may be configured to blow an air current to remove the electrolyte.

[0080] In the present embodiment, an example has been shown in which a metal plate is marked with an identification mark using an electrolytic marking processing device or electrolytic marking method without forming an oxide film, but the present invention is not limited to this. In the present invention, the metal plate may be a metal plate on which an identification mark is marked using an electrolytic marking processing device or electrolytic marking method and on which an oxide film is formed. In other words, the present embodiment includes cases in which an oxide film is formed by electrolytic marking and cases in which an oxide film is not formed. For example, the chemical analysis values ​​shown in Table 1 are an example of an analysis of a metal plate before and after marking with an identification mark using an electrolytic marking processing device according to the present invention, which is configured using the electrolytic marking method according to the present invention.

[0081]

[0082] As shown in Table 1, the metal plate material marked with an identification mark has an increased O (oxygen) ratio of approximately 14 mass %, and is thought to have formed an oxide film made of an oxide containing Cr. If the O (oxygen) ratio of the metal plate material is as high as shown in Table 1, the oxidation resistance of the surface of the metal plate material can be improved, and corrosion due to oxidation of the surface of the metal plate material can be expected to be suppressed.

[0083] REFERENCE SIGNS LIST 1 Unwinding section 2 Electrolytic marking processing section 3 Winding section 4 Cleaning section 5 Drying section 7 Deflector roll 8 Coating section 21 AC power supply section 22 Conductive roll section 22a Rotating shaft section 22b Insulating member 22c Through hole 23 Counter electrode member 24 Reservoir 30 Electrolyte 50 Metal plate material 60 Identification mark 100 Electrolytic marking processing device

Claims

1. A system comprising: an unwinding section which converts a roll of metal sheet material into a flat plate and sends it out; an electrolytic marking processing section which is located downstream of the unwinding section and which marks the metal sheet material with an identification mark; and a winding section which is located downstream of the electrolytic marking processing section and which winds up the metal sheet material marked with the identification mark into a roll; the electrolytic marking processing section includes: a rotating shaft section which constitutes one of a pair of electrodes; and an insulating member which surrounds the outer surface of the rotating shaft section and has one side in contact with the rotating shaft section, the other side in contact with the metal sheet material as the metal sheet material is wrapped around the insulating member and has a through hole extending from one side to the other side; a storage tank which stores an electrolyte and in which the wound portion of the metal sheet material around the insulating member is immersed; a counter electrode member which constitutes the other of the pair of electrodes and which contacts the metal sheet material; and an AC power supply section which has a pair of connection terminals which are electrically connected to the conductive roll section and the counter electrode member. The electrolytic marking processing unit is configured to mark the identification mark on the metal plate material via the electrolyte supplied to the through hole by immersion using AC power supplied by the AC power supply unit.

2. The electrolytic marking processing device according to claim 1, wherein the through hole has a shape corresponding to the identification mark and a plurality of through holes are provided.

3. The electrolytic marking processing device according to claim 1, wherein the counter electrode member is arranged on the upstream or downstream side of the conductive roll section and is constituted by a roll that rotates while in contact with the metal plate material.

4. A metal plate material having an identification mark marked thereon by the electrolytic marking processing device according to any one of claims 1 to 3.

5. The metal plate according to claim 4, wherein the metal plate is a bimetal.

6. A metal plate material on which an identification mark has been marked and an oxide film has been formed by the electrolytic marking processing device according to any one of claims 1 to 3.

7. A method for electrolytic marking comprising the steps of: supplying a metal sheet from an unwinding section to an electrolytic marking processing section; wrapping the metal sheet supplied to the electrolytic marking processing section around an outer surface of a rotating shaft section constituting a rotating conductive roll section, contacting one side of the metal sheet with the other side of an insulating member which surrounds the outer surface of the rotating shaft section and contacts the rotating shaft section, and immersing the wrapped portion of the metal sheet around the insulating member in an electrolyte stored in a storage tank, and supplying the electrolyte to a through hole extending from one side to the other side of the insulating member; supplying AC power between the metal sheet and the rotating shaft section while the wrapped portion of the metal sheet around the insulating member is immersed in the electrolyte, thereby forming and marking an identification mark on the metal sheet via the electrolyte supplied to the through hole; and winding up the metal sheet marked with the identification mark in a winding section.

8. A metal plate material having an identification mark marked thereon by the electrolytic marking method according to claim 7.

9. The metal sheet of claim 8, wherein the metal sheet is a bimetal.

10. A metal plate material on which the identification mark has been marked by the electrolytic marking method described in claim 7 and on which an oxide film has been formed.

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