Marking reading device for metal molding, management system for metal molding, and marking reading method for metal molding

Abstract

To provide a marking reading device, a management system, and a marking reading method, capable of improving the reading rate of a marking indicated on a metal molding.SOLUTION: A reading unit 50 includes: a first illumination device 51a that irradiates a can bottom portion 6a with light; a reader that captures an image of a marking M in synchronization with the irradiation timing of the first illumination device 51a; a second illumination device 52a that irradiates the can bottom portion 6a with light from a direction different from that of the first illumination device 51a in a state where the surface of the can bottom portion 6a is viewed from a normal direction; and a reader that captures an image of the marking in synchronization with the irradiation timing of the second illumination device 52a.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a marking reading device, a management system, and a marking reading method for metal formed products manufactured from rolled material. [Background technology]

[0002] Conventionally, in order to clearly image a marking on the surface of a rolled metal material, there has been a device that images the surface of the rolled material while illuminating it in a direction parallel to the rolling direction (for example, Patent Document 1). However, it is extremely difficult to store, transport, etc., metal molded products formed from rolled material so that the rolling direction is constant. For this reason, conventional devices have been unable to stably obtain clear images of metal molded products. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-123111 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a marking reading device, a management system, and a marking reading method that can clearly image markings on metal formed products manufactured from rolled material. [Means for solving the problem]

[0005] One form of the present invention is a marking reading device for a marking shown on a marking formation portion on the surface of a metal molded product manufactured, for example, from a rolled metal plate, characterized in that the device comprises a first illumination unit that irradiates light onto the marking formation portion, a first imaging unit that images the marking in synchronization with the irradiation timing of the first illumination unit, a second illumination unit that irradiates light onto the marking formation portion from a direction different from that of the first illumination unit while viewing the marking formation portion from a normal direction, and a second imaging unit that images the marking in synchronization with the irradiation timing of the second illumination unit. Moreover, one embodiment of the present invention is a marking reading method for a marking shown on a marking formation portion on the surface of a metal molded product manufactured, for example, from a rolled metal plate, characterized in that the method includes a first illumination step of irradiating light onto the marking formation portion, a first imaging step of imaging the marking in synchronization with the irradiation timing of the first illumination step, a second illumination step of irradiating light onto the marking formation portion from a direction different from that of the first illumination step while viewing the marking formation portion from the normal direction, and a second imaging step of imaging the marking in synchronization with the irradiation timing of the second illumination step. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a management system 1 for cans 6 according to an embodiment. [Diagram 2] 11 is a diagram for explaining information stored in a process history storage unit 25b in the embodiment. FIG. [Diagram 3] 10 is a diagram illustrating a state in which light L30 from an illumination device 30 according to an embodiment is reflected on the surface of a rolled metal material 5. FIG. [Figure 4] 11A to 11C are diagrams illustrating verification results in which a captured image of a can bottom 6a in an embodiment changes depending on an irradiation angle θ30. [Diagram 5] FIG. 2 is a diagram illustrating a reading unit 50 according to an embodiment. [Figure 6]FIG. 6 is an enlarged view of a portion of FIG. 5(C), illustrating the focusing of light by the focusing lens 53 of the embodiment and the reflection of light at the rim 6b of the can bottom 6a. [Figure 7] 1 is a diagram showing an example in which a reading unit 60 according to an embodiment is installed in the vicinity of a transport wheel 24d of an inspection device 24 as a reading unit 24b. [Figure 8] 1 is a diagram showing an example in which a reading unit 60 according to an embodiment is installed in the vicinity of a transport wheel 24d of an inspection device 24 as a reading unit 24b. [Figure 9] FIG. 13 is a diagram showing an example in which the reading unit 70 of the embodiment is attached to the mandrel wheel 23d of the printing device 23 as the reading unit 23b. [Figure 10] 2 is an enlarged view showing a configuration in the vicinity of a reading unit 70 according to an embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] (Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating the configuration of a management system 1 for cans 6 according to an embodiment. FIG. 2 is a diagram illustrating information stored in the process history storage unit 25b according to the embodiment. As shown in Fig. 1, management system 1 is a system for manufacturing cans 6 (metal formed products, metal formed cans) from rolled metal (aluminum, steel, etc.), and a system for managing the process history of the manufactured cans 6. The cans 6 manufactured by management system 1 are empty cans. In the embodiment, a two-piece can will be described as an example. In the embodiment, the can 6 is not limited to a finished product, but includes an intermediate product to be processed into the can 6 (for example, an intermediate product after a cupping press process, etc.). The can 6 has a rim 6b provided on the can bottom 6a (see FIG. 5(C) etc.). The rim 6b is a protrusion provided in an annular range on the periphery of the can bottom 6a when viewed in the can axial direction. The rim 6b protrudes downward in the can axial direction from this annular range. The management system 1 includes a manufacturing system 10 (a can manufacturing system) and a management device 25.

[0008] (Manufacturing System 10) The manufacturing system 10 is a system installed on a manufacturing line in a factory for manufacturing cans 6. The manufacturing system 10 includes a cupping press device 21, a can body processing device 22, a printing device 23, and an inspection device 24. The cupping press device 21, the can body processing device 22, the printing device 23, and the inspection device 24 can communicate with the management device 25 via a communication network 2 such as a LAN. In a configuration in which the management device 25 is provided in a management facility outside the manufacturing plant, in cloud computing, or the like, the communication network 2 may include a line such as the Internet.

[0009] In the embodiment, a computer refers to a device including an electronic calculator equipped with a storage device, a control device, an arithmetic device, etc., and the cupping press device 21, the can body processing device 22, the printing device 23, the inspection device 24, the management device 25, and the reading units 50, 60, 70 each include a storage unit, a control unit, etc., and are included in the concept of a computer. Furthermore, each device is not limited to being configured by a single electronic calculator, and may be configured by multiple electronic calculators as necessary. The storage unit is a storage device such as a hard disk or a semiconductor memory device for storing programs, information, etc. required for the operation of each device. The control unit is a device that performs arithmetic processing required for the operation of each device and controls each device in an integrated manner. The control unit is composed of, for example, a CPU (Central Processing Unit) etc. The control unit realizes various functions of the embodiment by appropriately reading and executing various programs stored in the storage unit.

[0010] The cupping press device 21, the can body processing device 22, the printing device 23, and the inspection device 24 are arranged in this order from the upstream side to the downstream side of the production line. The cupping press device 21, the can body processing device 22, the printing device 23, and the inspection device 24 are equipped with reading units 21b, 22b, 23b, and 24b, and control units 21i, 22i, 23i, and 24i, respectively.

[0011] The reading units 21b, 22b, 23b, and 24b are devices that read the markings M on the can bottom 6a in each process, as will be described later. In each process, when processing, etc. is carried out in multiple lanes, a reading unit may be provided in each lane, or one reading unit may be configured to read the markings M of cans 6 being processed, etc. in multiple lanes.

[0012] In the latter case, for example, one reading unit may read the marking M of a can 6 upstream of the lane, and then determine to which of the multiple lanes the read can 6 has moved. For example, in a can body processing process where multiple lanes are each provided with a can body processing device 22, one reading unit may be placed upstream of the lanes. This reading unit may be capable of communicating with a sorting device that sorts the cans 6 to the lanes. The reading unit may then obtain information from the sorting device as to which lane the can 6 whose marking M has been read has been transported.

[0013] The cupping press device 21 is a device that performs the cupping process. Although not shown in the drawings, the cupping press device 21 is equipped with a press machine and performs punching, drawing, and the like. In the punching process, the rolled material 5 pulled out from the rolls is punched into a disk shape using a punching die. In the drawing process, the rolled material 5 punched into a disk shape is drawn into a cup shape using a metal mold (die, punch, etc.). In the drawing process, the can bottom 6a is formed into a dome shape, a flat shape, etc. depending on the type of can 6. In the embodiment, the drawing process in the cupping step is also referred to as cupping, and the cup-shaped member machined from the rolled material 5 is also referred to as a metal cup, as appropriate.

[0014] The cupping press device 21 includes a marking device 21a. The marking device 21a is a device that prints or stamps the marking M in an area that forms the can bottom 6a of the can 6. The marking device 21a is, for example, an inkjet printer, a laser marker, or the like. The marking device 21a may print or stamp a marking M on the area of ​​the rolled material 5 that has been punched but not yet cupped, which will be processed into the can bottom 6a, or may print or stamp a marking M on the can bottom 6a of the metal cup produced by cupping the rolled material 5. The marking M is a display including can identification information that is identification information with which the can 6 can be identified. The can identification information may be, for example, a sequential number, a symbol, or the like. The marking M is a display in which the can identification information is coded. In the embodiment, an example is described in which the marking M is a two-dimensional code having information in which information including the can identification information is encoded, but the marking M is not limited to this, and may be, for example, a one-dimensional code or may be the can identification information itself (numbers, symbols, etc.). The can identification information may be issued by the marking device 21a. Alternatively, the management device 25 may issue the can identification information, and the marking device 21a may acquire the can identification information.

[0015] The can body processing device 22 is a device that executes a can body processing process (also called a body maker process). Although not shown in the drawings, the can body processing device 22 includes a processing device for ironing the metal cup, etc. In the ironing process, an ironing die is used to thinly stretch the can body in the can axial direction.

[0016] The printing device 23 is a device that executes the printing process. The printing device 23 includes a blanket 23f that transfers ink to the can body, a burnish roller 23h that applies a varnish, and the like (see FIG. 9).

[0017] The inspection device 24 is a device that executes the inspection process. Inspection device 24 is equipped with a camera that captures images of cans 6. Inspection device 24 can determine the quality of cans 6 (e.g., appearance inspection, dimensional inspection, etc.) by analyzing the captured images. Based on the quality results, inspection device 24 determines whether the appearance quality of cans 6 is OK (pass) or NG (reject).

[0018] The control units 21i, 22i, 23i, and 24i of each of the above devices correspond the can identification information obtained by decoding the marking M read by the inspection device 24 to the manufacturing information of the can 6, and output the can identification information-manufacturing information to the management device 25. The manufacturing information is information related to the manufacturing facilities of each device (see FIG. 2). The manufacturing information for each device is as follows: Cupping press device 21: punching die model numbers 1 to 5 Can body processing device 22: Lane numbers 1 to 5 Printing device 23: Blanket number 1-5 Inspection device 24: Inspection results NG, OK

[0019] In addition, the manufacturing information is not limited to the above information, but may be, for example, information on the processing date and time, processing conditions of each device (e.g., press pressure, feed speed during printing, temperature of various processing liquids, etc.), and may include two or more pieces of information.

[0020] (Management device 25) Management device 25 is a device that manages the manufacturing history of cans 6. Management device 25 is, for example, a device such as a server or a personal computer. The management device 25 includes a storage unit 25a and a control unit 25i. The storage unit 25a includes a process history storage unit 25b. As shown in FIG. 2, the process history storage unit 25b stores can identification information and manufacturing information in association with each other. The control unit 25i performs processes for storing and managing the manufacturing history in the process history storage unit 25b based on the can identification information-manufacturing information output from each device. The manufacturing history is a history of manufacturing information in the manufacturing process of the cans 6. For example, the marking M of a can 6 bearing a marking M having "can identification information=0001" is read by each of the reading units of the cupping press device 21, the can body processing device 22, the printing device 23, and the inspection device 24. Then, each device outputs the can identification information-manufacturing information having "can identification information=0001" to the management device 25. Based on the can identification information-manufacturing information transmitted from each device, the control unit 25i of the management device 25 associates the "can identification information=0001" with the manufacturing information of each device and stores them sequentially in the process history storage unit 25b. In this way, the management device 25 can store and manage the manufacturing history of the can 6 bearing a marking M having "can identification information=0001".

[0021] Here, the order of conveyance of the multiple cans 6 in the manufacturing process is irregular. For this reason, for example, even if the can 6 with "can identification information=0001" finishes processing before the can 6 with "can identification information=0002" in the cupping press process, the can 6 with "can identification information=0002" may be processed before the can 6 with "can identification information=0001" in the can body processing process. For this reason, the manufacturing history of the cans 6 cannot be managed based on the order in which they were manufactured.

[0022] In contrast, in the embodiment, the production history can be stored and managed based on the can identification information-production information output from each device. Therefore, the production information of each can 6 can be tracked based on the can identification information. This allows the management system 1 to manage the production information of cans 6 on the production line, cans 6 after shipment, etc., based on the can identification information of the can 6.

[0023] [Relationship between irradiation angle and captured image] Here, the relationship between the irradiation angle θ30 of the lighting device 30 that irradiates the can bottom with illumination light when reading the marking M, and the captured image of the can bottom 6a will be described. FIG. 3 is a diagram illustrating a state in which light L30 from an illumination device 30 according to the embodiment is reflected on the surface of a rolled metal material 5. As shown in FIG. In the embodiment, the angle between the optical axis of the illumination light from the illumination device and the rolling direction RD of the rolled metal material 5 when the surface of the rolled metal material 5 is viewed from the normal direction is also referred to as the irradiation angle θ30. The probability that the reading unit can decode the captured image of the marking M is also referred to as the reading rate.

[0024] 3, the surface of the rolled metal material 5 has a number of stripes along a rolling direction RD, which is one direction. The stripes are formed by grooves with a minute depth. When light L30 emitted by the lighting device 30 reaches the surface of the metal, it is diffusely reflected by the grooves. As shown in FIG. 3(A), the amount of light L30 from the lighting device 30 that is diffusely reflected on the surface of the metal increases as the irradiation angle θ30 approaches 90 degrees. 3(B), the amount of light L30 from the lighting device 30 that is specularly reflected by the metal surface increases as the irradiation angle θ30 approaches 0 degrees (i.e., as the optical axis of the lighting device 30 approaches parallelism with the rolling direction RD). In other words, the amount of diffusely reflected light decreases as the irradiation angle θ30 approaches 0 degrees.

[0025] (Verification of the image of marking M) FIG. 4 is a diagram illustrating the verification result that the captured image of the can bottom 6a of the embodiment changes depending on the irradiation angle θ30. FIG. 4 is a schematic diagram of a captured image. For reference, Fig. 4 also illustrates an obtuse irradiation angle θ30 that exceeds 90 degrees, but basically, if the absolute value of the difference between the irradiation angle θ30 and 90 degrees (|θ30-90 degrees|) is the same, the conditions for the irradiation angle θ30 are the same for acute and obtuse angles. For example, as shown in parentheses in Fig. 4, the irradiation angle θ30=100 degrees and the irradiation angle θ30=80 degrees have the same conditions.

[0026] In the verification, the marking M was engraved in the center of the can bottom 6a of an aluminum can 6 with a laser marker, and the can bottom 6a was irradiated at multiple irradiation angles θ30. The shape of the can bottom 6a is dome-shaped. The part of the can bottom 6a where the marking M was engraved (the marking formation part) is within a range that can be considered to be a surface perpendicular to the can axis. The angle of incidence of the light L30 on the can bottom 6a (the angle between the optical axis of the illumination light and the normal to the surface of the can bottom 6a) was 45 degrees. Then, an image was taken from directly above the can bottom 6a with a reader, and it was verified whether or not the can identification information could be decoded from the captured image of the marking M. 4, in the image of the marking M on the can bottom 6a, as the irradiation angle θ30 approaches 90 degrees, the influence of diffuse reflection becomes greater, and the contrast between the marking M and the exposed part of the metal surface becomes smaller. On the other hand, as the irradiation angle θ30 approaches 0 degrees, the contrast between the marking M and the exposed part of the metal surface becomes greater.

[0027] In addition, when the irradiation angle θ30 was 80 degrees, 90 degrees, or 100 degrees, the captured image of the marking M was unclear, and therefore it was impossible to decode the can identification information. On the other hand, when the irradiation angle θ30 was 0 degrees, 60 degrees, 70 degrees, and 110 degrees, 120 degrees, or 130 degrees, Because the image of the marking M was clear, it was possible to decode the can identification information. From these results, it was confirmed that when the irradiation angle θ30 is between 80 degrees and 100 degrees, the image of the marking M is unclear and it is impossible to decode the can identification information; on the other hand, when the irradiation angle θ30 is between 70 degrees and 110 degrees, the image of the marking M is clear and it is possible to decode the can identification information.

[0028] That is, in this verification, it was confirmed that the state in which decoding based on marking M is most difficult is when the irradiation angle θ30 is 90 degrees. It was also confirmed that the reading rate of marking M improves as the irradiation angle θ30 deviates from the state in which the irradiation angle θ30 is 90 degrees.

[0029] [Reading units 50, 60, 70] The reading units 50, 60, and 70 will now be described in detail. (Reading unit 50 (basic configuration)) FIG. 5 is a three-sided view illustrating the reading unit 50 according to the embodiment. FIG. 5(A) is a view of FIG. 5(B) seen from the left side (a direction perpendicular to the can axis in FIG. 5(B) as seen from the first lighting device 51a side). FIG. 5(B) is a diagram showing reading unit 50 when the surface of can bottom 6a of can 6 placed at the reading position is viewed from below in the can axial direction. FIG. 5(C) is a diagram of FIG. 5(B) viewed from below (a diagram of FIG. 5(B) viewed from the second lighting device 52a side in a direction perpendicular to the can axis). FIG. 6 is an enlarged view of a portion of FIG. 5(C), illustrating the focusing of light by the focusing lens 53 of the embodiment and the reflection of light at the rim 6b of the can bottom 6a. In the drawings, only the surface (outer surface) of the can 6 is shown, and the thickness of the can 6 is omitted. In the embodiment, the normal direction of the apex of the dome of the can bottom 6a (the surface of the can bottom 6a) coincides with the can axial direction (the direction of the central axis of the can 6). The state when viewed in the normal direction of the apex of the dome of the can bottom 6a is the same as the state when viewed from the can axial direction (the direction of the central axis of the can 6).

[0030] The reading unit 50 is the basic configuration of the reading unit of the embodiment. Reading unit 50 includes first lighting device 51a, second lighting device 52a, reader 55 (one imaging unit), and control unit 59. First lighting device 51a, second lighting device 52a, and reader 55 are fixed around can 6 placed at the reading position by fixing members (not shown) such as brackets or stays. The first lighting device 51a and the second lighting device 52a are devices that irradiate the can bottom 6a with illumination lights L51a and L52a, respectively. The first lighting device 51a is installed so that the optical axis (the central axis of the light flux of the illumination light L51a) faces the center of the surface of the can bottom 6a (i.e., the top of the dome). The incidence angle θ50a of the illumination light L51a of the first lighting device 51a on the surface of the can bottom 6a is set to an illuminance that allows the marking M to be decoded, for example, 40 degrees or more and 55 degrees or less. If the incidence angle θ50a is too small, the illuminance increases, but diffuse reflection light due to rolling is more likely to enter. On the other hand, if the incidence angle is too large, the rim 6b blocks the light to the installation range of the marking M.

[0031] As shown in FIG. 6, the first illumination device 51a includes a condenser lens 53. The condenser lens 53 is an optical member that condenses the illumination light L51a (see hatching in FIG. 6) emitted by the first lighting device 51a onto the inside of the rim 6b of the can bottom 6a. The condenser lens 53 may be provided inside the first lighting device 51a or outside the first lighting device 51a. The height h51a of the first lighting device 51a (the distance between the light-emitting portion of the first lighting device 51a and the top of the can bottom 6a) is, for example, about 15 mm or more.

[0032] Here, the can bottom 6a is provided with a rim 6b that contacts the ground surface. The rim 6b is provided so as to protrude downward in the can axial direction from the range of the outer edge of the can bottom 6a. The light L51d (see dotted line) that reaches the rim 6b is reflected by the surface of the rim 6b and travels toward the inside of the can bottom 6a. In this way, the reflected light that travels toward the inside of the can bottom 6a excessively increases the illuminance of the can bottom 6a or is reflected by the surface of the can bottom 6a. For this reason, such reflected light causes the captured image of the marking M to become unclear. The amount of reflected light is greater in the case of regular reflection than in the case of diffuse reflection. Therefore, the captured image of the marking M is more susceptible to the influence of the light reflected by the rim 6b as the irradiation angle becomes smaller (i.e., as the optical axis of the illumination light L51a of the first illumination device 51a approaches parallel to the rolling direction when viewed from the can axis direction).

[0033] The condenser lens 53 condenses the illumination light L51a of the first illumination device 51a onto the inside of the rim 6b, and thus sufficiently reduces the light components that reach the rim 6b, thereby reducing the reflected light. This allows the reading unit 50 to prevent the captured image of the marking M from becoming unclear, and improves the reading rate. 6 illustrates a state in which the entire illumination light L51a is focused on the inside of the rim 6b, but it is sufficient if light L51d that is about to reach the inner surface of the rim 6b (more specifically, the portion of the inner surface of the rim 6b that faces the first lighting device 51a) can be focused on the inside of the rim 6b. That is, this is because light L51e (see dotted line) that reaches the outer surface of the rim 6b (the portion of the outer surface of the rim 6b that faces the first lighting device 51a) is basically reflected toward the outside of the rim 6b.

[0034] The second lighting device 52a is a device similar to the first lighting device 51a. That is, the direction of the optical axis of the second lighting device 52a is directed toward the center of the can bottom 6a. In addition, the incident angle of the illumination light of the second lighting device 52a to the can bottom 6a, the installation height of the second lighting device 52a, etc. are similar to those of the first lighting device 51a. Furthermore, the second lighting device 52a includes a condenser lens (not shown). Furthermore, as shown in FIG. 5(B), when viewed from the can axis direction, the optical axis of the illumination light L51a of the first lighting device 51a and the optical axis of the illumination light L52a of the second lighting device 52a are perpendicular to each other, that is, the angle θ50b between the two optical axes is a right angle.

[0035] The reader 55 is a device having a camera function for acquiring an image of the can bottom 6a. It is preferable that the optical axis O55 of the reader 55 (the optical axis of the optical lens of the reader 55) coincides with the can axis direction. This reduces distortion of the captured image of the marking M when the marking M is provided near the dome-shaped top of the can bottom 6a. However, as with readers 71b, 72b, etc. described below, the optical axis of the reader may be slightly inclined with respect to the can axis due to reasons such as the installation space for the reader, as long as the distortion of the captured image is sufficiently small and the image of the marking M can be decoded. The installation height h55 of the reader 55 (the distance between the light entrance part of the reader 55 and the top of the can bottom 6a) is, for example, about 200 mm.

[0036] With the above configuration, the control unit 59 acquires imaging information of the can bottom 6a (first imaging step) by controlling the reader 55 when the illumination of the first illumination device 51a is turned on (first illumination step). Furthermore, the control unit 59 acquires imaging information of the can bottom 6a by controlling the reader 55 when the illumination of the second illumination device 52a is turned on (second illumination step) after the first illumination device 51a is turned off (second imaging step). Then, the control unit 59 executes a process for decoding the marking M and acquiring the can identification information based on these two pieces of image information.

[0037] As described above, the angle θ50b between the optical axis of the illumination light L51a and the optical axis of the illumination light L52a is 90 degrees when viewed from the can axis direction. Therefore, even if the control unit 59 cannot decode based on one piece of imaging information, there is an extremely high probability that it can decode based on the other piece of imaging information. This is because even if the irradiation angle θ30 of one lighting device is within the range of 80 degrees≦θ30≦100 degrees, the irradiation angle θ30 of the other lighting device is within the range of 0 degrees≦θ30<80 degrees or 100 degrees<θ30≦180 degrees (see FIG. 4). That is, more specifically, when the irradiation angle θ30 of one lighting device is within the range of 80 degrees≦θ30≦100 degrees, the irradiation angle θ30 of the other lighting device is within the range of 0 degrees≦θ30≦10 degrees or 170 degrees≦θ30≦180 degrees. Furthermore, even if the irradiation angle θ30 of one lighting device is within the range of 70 degrees<θ30<110 degrees, the irradiation angle θ30 of the other lighting device is within the range of 0 degrees≦θ30<20 degrees or 160 degrees<θ30≦180 degrees. Furthermore, referring to the verification results in Figure 4, in order to improve the reading rate of marking M, it is not limited to θ50b = 90 degrees, but it is preferable that 20 degrees < θ50b < 160 degrees, and it is more preferable that 40 degrees ≦ θ50b ≦ 140 degrees.

[0038] (Reading units 60, 70) The reading unit can have various configurations depending on the state of the can 6 to be read. That is, in the manufacturing process, the can 6 rotates about its axis and moves for transportation, etc. The reading unit can have various configurations depending on the state of the can 6. The basic configuration of the reading units 60 and 70 for capturing an image of the can bottom 6 a is similar to that of the reading unit 50 . For example, the installation height of each illumination device and each reader of reading units 60, 70 is the same as the installation height of illumination devices 51a, 52a and reader 55 of reading unit 50. The incidence angle of each illumination device of reading units 60, 70 to can bottom 6a is the same as the incidence angle of illumination devices 51a, 52a of reading unit 50 to can bottom 6a. When viewed from the can axial direction, the optical axis of each first illumination device and the optical axis of each second illumination device are perpendicular to each other.

[0039] (Reading unit 60, inspection device 24) Reading unit 60 is configured to be suitable for reading marking M when can 6 is not rotating around the can axis and is moving (moving in a direction perpendicular to the can axis). In the embodiment, an example in which reading unit 60 is provided in inspection device 24 will be described. 7 and 8 are three-sided views illustrating the reading unit 60 according to the embodiment. 7 and 8 show an example in which the reading unit 60 is installed in the vicinity of the transport wheel 24d of the inspection device 24 as the reading unit 24b (see FIG. 1). FIG. 7 shows a state in which the can 6 is disposed in the first position P61. 7(A) to 7(C) correspond to the illustrated directions of FIGS. 5(A) to 5(C), respectively. FIG. 8 shows a state in which the transport wheel 24d has rotated from the state shown in FIG. 7, so that the can 6 is disposed at the second position P62. FIG. 8(A) is a view of FIG. 8(B) viewed from the left of tangent B (a tangent to the arc that is the movement trajectory of the center of can 6, which passes through the center of can 6 placed at second position P62). FIG. 8(B) is a diagram showing the reading unit 60 when the can 6 disposed at the second position P62 is viewed from below in the can axial direction. FIG. 8(C) is a view of FIG. 8(B) viewed from the outside in radial direction C (the direction of a straight line passing through the center of the can 6 placed at the second position P62 within the diameter of the transport wheel 24d). It should be noted that the first reader 61b is omitted in FIGS. 7(A) and 8(A).

[0040] As shown in FIG. 7, the inspection device 24 includes a transport wheel 24d. The transport wheel 24d is a member having a disk shape, a cylindrical shape, or the like. The outer periphery of the transport wheel 24d has a plurality of arc-shaped cutouts 24e (also called pockets, etc.). The cans 6 are accommodated in these cutouts 24e, and the transport wheel 24d rotates around its central axis (see arrow θ24d), causing the cans 6 to move along the outer periphery of the transport wheel 24d (see arrow A24d). The shape of the cutouts 24e may be an arc shape that opens widely outward in the radial direction. Conveyor wheel 24d of inspection device 24 is provided with a suction device (not shown) that sucks up accommodated cans 6 and holds them in notches 24e. As a result, conveyor wheel 24d of inspection device 24 moves cans 6 accommodated in notches 24e without rotating them around the can axis.

[0041] The reading unit 60 includes a first unit 61, a second unit 62, and a control unit 69. The first unit 61 reads the marking M on the can bottom 6a when the can 6 is placed in the first position P61. The second unit 62 reads the marking M on the can bottom 6a when the can 6 is placed in the second position P62. The second position P62 is a position rotated about a few degrees circumferentially from the first position P61 (see FIG. 8). That is, as the can 6 passes the first position P61, the first unit 61 captures an image of the marking M. Thereafter, as the can 6 moves from the first position P61 along the outer periphery and passes the second position P62, the second unit 62 captures an image of the marking M. The first position P61 and the second position P62 may be spaced apart enough so that a first reader 61b and a second reader 62b, which will be described later, do not interfere with each other.

[0042] The first unit 61 includes a first illumination device 61a and a first reader 61b (first imaging section). As shown in Figure 7 (B), when viewed from the can axial direction, the optical axis of the illumination light L61a from the first lighting device 61a points toward the center of the can 6 placed at the first position P61 and is tangent to the arc (see the arc-shaped arrow A24d) that is the movement trajectory of the center of the can 6. As shown in FIG. 7(C), the optical axis O61b of the first reader 61b coincides with the axial direction of the can 6 placed at the first position P61.

[0043] The second unit 62 includes a second illumination device 62a and a second reader 62b (a second imaging section). 8(A), the optical axis O62b of the second reader 62b coincides with the can axial direction of the can 6 placed at the second position P62. The optical axis of the illumination light L62a is directed toward the center of the can bottom 6a of the can 6 placed at the second position P62, and is in the normal direction of the arc that is the movement trajectory of the center of the can 6 when viewed from the can axial direction (i.e., the radial direction C). In this way, second lighting device 62a and second reader 62b are installed according to the position of can 6 after it has been moved to second position P62. This allows second unit 62 to read marking M in a manner that compensates for the movement of can 6 caused by the rotation of transport wheel 24d.

[0044] As shown in Fig. 7(C) and other figures, the control unit 69 controls the first lighting device 61a when the can 6 passes the first position P61 to irradiate the can bottom 6a with illumination light L61a (first lighting step). The control unit 69 also controls the first reader 61b in synchronization with the control of the first lighting device 61a to capture an image of the can bottom 6a while the first lighting device 61a is illuminating the can bottom 6a (first imaging step). Then, the control unit 69 turns off the illumination of the first lighting device 61a while the can 6 moves from the first position P61 to the second position P62.

[0045] As shown in Fig. 8(A) and other figures, the control unit 69 then controls the second lighting device 62a when the can 6 passes the second position P62 to irradiate the can bottom 6a with illumination light L62a (second lighting step). The control unit 69 also controls the second reader 62b in synchronization with the control of the second lighting device 62a to capture an image of the can bottom 6a while the second lighting device 62a is illuminating the can bottom 6a (second imaging step). Then, the control unit 69 turns off the illumination of the second lighting device 62a until the next can 6 moves to the first position P61.

[0046] As a result, when the can 6 is placed at the first position P61 and the second position P62, the control unit 69 of the reading unit 60 can obtain the imaging information of the marking M from the first reader 61b and the second reader 62b, respectively, and then obtain the can identification information by decoding processing. Then, when the control unit 69 is able to obtain the can identification information from both the imaging information from the first reader 61b and the imaging information from the second reader 62b, it only needs to output the can identification information obtained from at least one of them to the control unit 24i of the inspection device 24. On the other hand, when the control unit 69 is able to obtain the can identification information from only one of the imaging information from the first reader 61b and the imaging information from the second reader 62b, it only needs to output the can identification information obtained from only one of them to the control unit 24i of the inspection device 24.

[0047] Control unit 24i of inspection device 24 associates the can identification information acquired from reading unit 60 with the inspection result (OK or NG) of can 6, and outputs them to management device 25.

[0048] (Reading unit 70, printing device 23) The reading unit 70 is configured to be suitable for reading the marking M when the can 6 is rotating around the can axis and moving. In the embodiment, an example in which the reading unit 70 is provided near the printing device 23 will be described. FIG. 9 is a diagram showing an example in which the reading unit 70 of the embodiment is attached to the mandrel wheel 23d of the printing device 23 as the reading unit 23b (see FIG. 1). FIG. 10 is an enlarged view showing the configuration in the vicinity of the reading unit 70 according to the embodiment. The directions shown in FIGS. 10(A) to 10(C) correspond to the directions shown in FIGS. 5(A) to 5(C), respectively.

[0049] 9, the printing device 23 includes a mandrel wheel 23d, a blanket 23f, and a burnish roller 23h. Although not shown, the printing device 23 includes a plate cylinder and other components that apply ink to the blanket 23f. Mandrel wheel 23d rotates about its central axis (see arrow θ23d), thereby moving can 6 held by mandrel 23e along a circumference centered on the central axis (see arrow A23d). As will be described later, in the printing process, the can 6 held by the mandrel 23e rotates about the can axis.

[0050] The blanket 23f is a plate that prints on the outer peripheral surface of the can body while the can 6 is held by the mandrel 23e. In FIG. 9, the blanket number is shown in parentheses next to the reference number of the blanket 23f. Five blankets 23f (23f(1) to 23f(5)) are fixed in the circumferential direction to the outer peripheral surface of a cylindrical blanket roller 23g. While the blanket roller 23g rotates around its central axis (see arrow θ23g), each blanket 23f transfers ink to the outer peripheral surface of the can body of the can 6. In response to this, the can 6 rotates around the can axis (see arrow θ1). The burnish roller 23h is a device that applies a varnish to the outer peripheral surface of the can 6 after printing in order to protect the outer peripheral surface of the can 6. The varnish is attached to the outer peripheral surface of the burnish roller 23h. The burnish roller 23h applies the varnish to the outer peripheral surface of the can body by rotating in the same manner as the blanket roller 23g (see arrow θ23h). In response to this, the can 6 rotates around the can axis (see arrow θ2).

[0051] The reading unit 70 reads the marking M on the can bottom 6a of the can 6 after the varnish has been applied. Therefore, the reading position P70 of the reading unit 70 is a position to which the can 6 after being coated with varnish has moved along a circumference centered on the central axis of the mandrel wheel 23d.

[0052] The reading unit 70 includes a first unit 71 and a second unit 72 . The imaging operation of second unit 72 is performed after the imaging operation of first unit 71. However, the period between the two imaging operations is sufficiently short (e.g., 1 / 100 seconds or less). Therefore, during the period between the two imaging operations, the rotation angle of can 6 about the can axis is, for example, 10 degrees or less, and the movement distance of can 6 is so small that it can be ignored. In the embodiment, it is assumed that first unit 71 and second unit 72 acquire images with can 6 placed at the same position. In other words, the position where can 6 is placed when first unit 71 and second unit 72 capture an image of can bottom 6a is assumed to be reading position P70.

[0053] The first unit 71 includes a first illumination device 71a and a first reader 71b (first imaging section). The optical axis of the first lighting device 71a is the same as the optical axis of the first lighting device 61a, that is, when viewed from the can axial direction, it points toward the center of the can 6 placed at the reading position P70 and is tangent to the arc (see arc-shaped arrow A23d) that is the movement trajectory of the center of the can 6. The first reader 71b is disposed in the space above the can bottom 6a disposed at the reading position P70 so as to be able to image the can bottom 6a. The optical axis O71b of the first reader 71b passes through the center of the can bottom 6a disposed at the reading position P70. The optical axis O71b of the first reader 71b does not coincide with the can axis direction, that is, the first reader 71b is disposed at a slight angle with respect to the can axis 6d (see FIG. 10(A)).

[0054] The second unit 72 includes a second illumination device 72a and a second reader 72b (second imaging section). The configuration of the second illumination device 72a is the same as that of the second illumination device 62a, except that, when viewed from the can axis direction, the optical axis of the illumination light L72a of the second illumination device 72a and the optical axis of the illumination light L71a of the first illumination device 71a are perpendicular to each other (see FIG. 10(B)).

[0055] As shown in FIGS. 9 and 10(B), when viewed from the can axial direction, the first leader 71b and the second leader 72b are arranged side by side in the radial direction of the mandrel wheel 23d. As shown in Fig. 10(A), when viewed from a direction perpendicular to the can axis (a tangent direction of a circle centered on the central axis of the mandrel wheel 23d), the first leader 71b and the second leader 72b are disposed at the same height. Therefore, the distance between the first leader 71b and the can bottom 6a is equal to the distance between the second leader 72b and the can bottom 6a. The first leader 71b and the second leader 72b are disposed so as to be line-symmetrical with respect to the can axis 6d. The angle between the optical axis O71b of the second leader 72b and the can axis 6d is equal to the angle between the optical axis O72b of the second leader 72b and the can axis 6d, and is, for example, about 5 degrees to 10 degrees.

[0056] In this way, the first reader 71b and the second reader 72b are arranged with a slight radial shift, so that they are arranged at the same height without interfering with each other. This allows the first reader 71b and the second reader 72b to capture an image of the can bottom 6a with the can 6 placed in the same position. The first reader 71b and the second reader 72b capture an image of the marking M on the can bottom 6a at an angle of about 5 to 10 degrees from the can axis. Distortion of the captured image caused by this degree of inclination has almost no effect on decoding of the marking M.

[0057] As shown in Fig. 10(C), when the can 6 passes the reading position P70, the control unit 79 controls the first lighting device 71a to irradiate the can bottom 6a with illumination light L71a (first lighting step). The control unit 79 also controls the first reader 71b in synchronization with the control of the first lighting device 71a to capture an image of the can bottom 6a while the first lighting device 71a is illuminating the can bottom 6a (first imaging step). The control unit 79 controls the first lighting device 71a to turn off within 1 / 100 seconds or the like after starting illumination.

[0058] As shown in Fig. 10(A), the control unit 79 then controls the illumination of the second illumination device 72a to irradiate the can bottom 6a with illumination light L72a (second illumination step). The control unit 79 also controls the second reader 72b in synchronization with the control of the second illumination device 72a to capture an image of the can bottom 6a while the second illumination device 72a is illuminating the can bottom 6a (second imaging step). The control unit 79 then turns off the illumination of the second illumination device 72a until the next can 6 moves to the reading position P70.

[0059] As a result, with the can 6 placed in the same position, the control unit 79 of the reading unit 70 can obtain the imaging information of the marking M from each of the first reader 71b and the second reader 72b, and then obtain the can identification information by decoding processing. Then, like the control unit 69 of the reading unit 60, when the control unit 79 is able to obtain the can identification information from both the imaging information from the first reader 71b and the imaging information from the second reader 72b, it only needs to output the can identification information obtained from at least one of them to the control unit 23i of the printing device 23. When the control unit 79 is able to obtain the can identification information from only one of the imaging information from the first reader 71b and the imaging information from the second reader 72b, it only needs to output the can identification information obtained from only one of them to the control unit 23i of the printing device 23.

[0060] During the period between the timing when the first reader 71b acquires the image information and the timing when the second reader 72b acquires the image information, the can 6 held by the mandrel 23e rotates around the can axis by inertia in association with the rotation of the burnish roller 23h. This period is within 1 / 100 seconds or the like. Therefore, the rotation angle of the can 6 during this period is within 10 degrees or the like. Also, when viewed from the can axis direction, the angle formed by the optical axis of the first lighting device 71a and the optical axis of the second lighting device 72a is 90 degrees. Therefore, even if the irradiation angle θ30 (see FIG. 4) of one of the first lighting device 71a and the lighting device 72a is 80 degrees or more and 100 degrees or less (i.e., |θ30-90 degrees|≦10 degrees), the irradiation angle θ30 of the other lighting device is less than 80 degrees or greater than 100 degrees. That is, as mentioned above, when the illumination angle θ30 of one lighting device is within the range of 80 degrees≦θ30≦100 degrees, the illumination angle θ30 of the other lighting device is within the range of 0 degrees≦θ30≦10 degrees or 170 degrees≦θ30≦180 degrees. In this case, even if can 6 rotates by about 10 degrees due to inertia, the other irradiation angle θ30 will be within the range of 0 degrees≦θ30≦20 degrees or 160 degrees≦θ30≦180 degrees (that is, 20 degrees≦|θ30-90 degrees|). This allows the control unit 79 to improve the probability of being able to decode the marking M based on the captured image of the other of the first reader 71b and the second reader 72b.

[0061] The control unit 23i of the printing device 23 outputs to the management device 25 the can identification information, blanket number (1 to 5), and printing plate number (not shown) acquired from the reading unit 70 in association with each other. The control unit 79 can determine the number of the mandrel 23e that held the can 6 when printing on each can 6, the blanket numbers 1 to 5, and the plate number of the printing plate by using a detection unit such as an encoder. The control unit 23i can also determine which of the multiple mandrels 23e is located at the printing position or the reading position. Therefore, the control unit 23i can associate the blanket numbers 1 to 5 with the can identification information acquired based on the image information of the can 6 placed at the reading position.

[0062] As described above, the reading units 60, 70 are attached to the inspection device 24 and the printing device 23, but the reading units can have various configurations depending on the manufacturing device to which they are attached. For example, the reading unit to be attached to a manufacturing device in which the cans 6 do not rotate around the can axis and do not move the cans 6 may be the basic reading unit 50 (see FIG. 5) as is. In this case, the first lighting device 51a and the second lighting device 52a sequentially illuminate the can bottoms 6a of the cans 6 arranged at the same position (first illumination step, second illumination step), and the reader 55 captures images of the can bottoms 6a at the illumination timings of the first lighting device 51a and the second lighting device 52a (first imaging step, second imaging step).

[0063] In addition, in a manufacturing device (such as the printing device 23) in which the can 6 rotates around the can axis and moves, the first lighting device may irradiate light of a first wavelength, and the second lighting device may irradiate light of a second wavelength that is different from the first wavelength. In this case, the first lighting device and the second lighting device may simultaneously irradiate light of the first wavelength and light of the second wavelength to the can 6 arranged at the same position (first lighting step, second lighting step). In this case, the first reader may be a device capable of capturing an image of the light of the first wavelength reflected by the can bottom 6a, and the second reader may be a device capable of capturing an image of the light of the second wavelength reflected by the can bottom 6a. The first reader and the second reader may capture an image of the can bottom 6a at the same irradiation timing of the first lighting device and the second lighting device (first imaging step, second imaging step).

[0064] In addition, when the reader is a device capable of capturing images of the first wavelength light and the second wavelength light independently, one reader may serve as both the first reader and the second reader. In this case, the reader may be configured to be capable of acquiring a plurality of captured images by capturing images continuously in one imaging operation, or may be configured to include a half mirror or the like that separates the subject light.

[0065] As described above, the reading unit of this embodiment can improve the reading rate of the marking M indicated on the can bottom 6a of the can 6 during the manufacturing process.

[0066] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and various modifications and changes are possible, such as the modified forms described below, which are also within the technical scope of the present invention. Furthermore, the effects described in the embodiment are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiment. Note that the configurations of the above-mentioned embodiment and the modified forms described below can be used only in part, or in appropriate combination, but detailed description will be omitted.

[0067] (Variations) (1) In the embodiment, the manufacturing system includes a cupping press device, a can body processing device, a printing device, and an inspection device, but is not limited to this. The manufacturing system may include various devices for manufacturing cans (for example, a cleaning device, a neck processing device that performs a process such as drawing the opening edge of the can, etc.). In addition, the reading unit may be provided in a device that fills empty cans with beverages, etc.

[0068] (2) In the embodiment, the angle between the optical axis of the first lighting device and the optical axis of the second lighting device when viewed from the can axis direction is 90 degrees, but this is not limited to this. This angle may be such that when one of the two readers cannot decode the can identification information based on the marking included in the captured image acquired by the other reader, the can identification information can be decoded based on the captured image acquired by the other reader. In other words, this angle may be such that the can identification information can be decoded based on at least one of the two captured images acquired by the two readers.

[0069] (3) In the embodiment, the marking is formed by laser marking or printing ink, but the marking is not limited to this. For example, the marking may be formed by attaching a sticker. In the case of a metal molded can or the like on which paint is applied in a spray process, the print contrast is reduced. Markings formed by laser marking are easily affected by paint, but the method of the embodiment is less susceptible to diffused light from lighting compared to, for example, ring lighting. This makes it possible to suppress a decrease in readability after paint is applied, even for markings formed by laser marking. (4) In the above embodiment, the cans are conveyed along a circumference, but the present invention is not limited to this. For example, the cans may be conveyed along a straight line.

[0070] (5) In the embodiment, an example in which the lighting device includes a condensing lens has been shown, but this is not limiting. For example, if the rim does not block the light from the lighting device, such as when the distance between the lighting device and the bottom of the can is sufficiently small, the lighting device does not need to include a condensing lens. On the other hand, if the rim blocks the light from the lighting device, such as when the distance between the lighting device and the bottom of the can is large, the lighting device only needs to include a condensing lens.

[0071] (6) In the embodiment, the marking forming portion (the portion where the marking is formed) is the bottom of the metal can, but is not limited thereto. The marking forming portion is not limited as long as it is the surface of the metal can and is within a range that can be imaged by the reading unit, and may be, for example, the peripheral surface of the can body, the top surface of the can lid, etc. Furthermore, the markings read by the reading unit are not limited to markings formed on metal molded cans, but may also be markings formed on other types of metal molded products (including those that involve a predetermined movement or rotation) manufactured by shaping rolled metal material. Furthermore, the shape of the metal can is not limited to a cylindrical shape, but may be substantially cylindrical (including a cross-sectional shape having an elliptical curved shape), or may be circular or substantially circular (including an elliptical shape) in cross-sectional shape. [Explanation of symbols]

[0072] 1: Management system 6: Can 6a: Can bottom 6b: Rim 21b, 22b, 23b, 24b, 50, 60, 70: Reading unit 30: Lighting equipment 51a, 61a, 71a: 1st lighting device 52a, 62a, 72a: 2nd lighting device 53: Condenser lens 55: Leader 61,71: 1st unit 61b, 71b: First Leader 62,72: 2nd unit 62b, 72b: Second Leader M: Marking

Claims

1. A marking reading device for a marking indicated on a marking formation portion on a surface of a metal molded product manufactured from a rolled metal plate, comprising: a first illumination unit that irradiates light onto the marking forming unit; a first imaging unit that images the marking in synchronization with an irradiation timing of the first illumination unit; a second illumination unit that irradiates the marking forming portion with light from a direction different from that of the first illumination unit when the marking forming portion is viewed from a normal direction; a second imaging unit that images the marking in synchronization with the irradiation timing of the second illumination unit; A marking reading device for a metal molded product.

2. The cross-sectional shape of the metal molded product is approximately circular.

2. The marking reading device for a metal molded product according to claim 1,

3. The metal part is generally cylindrical in shape.

2. The marking reading device for a metal molded product according to claim 1,

4. The metal molded product is a metal molded can, The marking forming portion is a bottom portion of the metal molded can.

2. The marking reading device for a metal molded product according to claim 1,

5. the marking reading device is a device for capturing an image of the marking of the marking forming unit when the metal molded product is disposed at a first position and a second position moved from the first position, When the metal molded product is disposed at the first position, the first illumination unit is disposed at a position where it irradiates the marking forming unit with light, and the first imaging unit is disposed at a position where it images the marking, When the metal molded product is disposed at the second position, the second illumination unit is disposed at a position where it irradiates the marking forming unit with light, and the second imaging unit is disposed at a position where it images the marking.

5. The marking reading device for a metal molded product according to claim 1, wherein the marking reading device is a metal molded product.

6. the marking reading device is a device for imaging the marking of the marking forming portion while the metal molded product is in a stationary state, The first illumination unit and the second illumination unit irradiate the marking forming unit with light at different timings, The first imaging unit and the second imaging unit are a single imaging unit, The one imaging unit images the marking at the respective illumination timings of the first illumination unit and the second illumination unit.

5. The marking reading device for a metal molded product according to claim 1, wherein the marking reading device is a metal molded product.

7. the marking reading device is a device for capturing an image of the marking of the marking forming portion in a state in which the metal molded product is rotating and in a state in which the metal molded product is disposed at a first position and a second position moved from the first position; The first position and the second position have a small separation distance that can be approximated to the same position, a rotational movement of the metal molded article between the first position and the second position is sufficiently small; When the metal molded product is disposed at the first position, the first illumination unit is disposed at a position where it irradiates the marking forming unit with light, and the first imaging unit is disposed at a position where it images the marking, When the metal molded product is disposed at the second position, the second illumination unit is disposed at a position where it irradiates the marking forming unit with light, and the second imaging unit is disposed at a position where it images the marking.

5. The marking reading device for a metal molded product according to claim 1, wherein the marking reading device is a metal molded product.

8. the marking reading device is a device for capturing an image of the marking of the marking forming portion while the metal molded product is rotating and moving, The first illumination unit emits light having a first wavelength, The second illumination unit emits light having a second wavelength that is different from the first wavelength at the same timing as the first illumination unit, The first imaging unit reads the marking based on an intensity of light corresponding to the first wavelength, The second imaging unit images the marking based on the intensity of light corresponding to the second wavelength.

5. The marking reading device for a metal molded product according to claim 1, wherein the marking reading device is a metal molded product.

9. the marking has encoded thereon information; When the marking formation portion of the metal molded product arranged at the reading position is viewed from a normal direction, an angle formed by an irradiation direction of the first illumination unit and an irradiation direction of the second illumination unit is such that the marking can be decoded based on at least one of the imaging information acquired by the first imaging unit and the imaging information acquired by the second imaging unit.

5. The marking reading device for a metal molded product according to claim 1, wherein the marking reading device is a metal molded product.

10. When the marking forming portion of the metal molded product arranged at the reading position is viewed from the normal direction, the angle θ between the irradiation direction of the first illumination unit and the irradiation direction of the second illumination unit is 20 degrees < θ < 160 degrees.

10. The marking reading device for a metal molded product according to claim 9.

11. the can bottom of the metal can has a protrusion protruding downward within an annular range, and the marking is provided on a surface on an inner side of the annular range, The first illumination unit and the second illumination unit condense illumination light to a region inside the annular range.

5. The marking reading device for a metal molded product according to claim 4.

12. A plurality of processing devices of different types that execute the process of manufacturing the metal molded product; a marking reading device for a metal molded product according to any one of claims 1 to 4, which is provided in each of the plurality of processing devices; A management system for the metal molded product, comprising a management device capable of communicating with each of the processing devices, The marking has identification information of the metal molded product, Each of the processing devices is The marking reading information acquired by each of the marking reading devices is associated with processing information, and the associated information is output to the management device; The management device includes: A storage unit; and a control unit that executes a process of storing in the storage unit, in association with identification information of each of the metal molded products and the processing information of the multiple types of the processing devices, based on outputs from the multiple processing devices.

4. The management system for metal molded products according to claim 1,

13. A method for reading a marking shown on a marking formation portion on a surface of a metal molded product manufactured from a rolled metal plate, comprising the steps of: a first illumination step of irradiating the marking forming portion with light; a first imaging step of imaging the marking in synchronization with irradiation timing of the first illumination step; a second illumination step of irradiating the marking forming portion with light from a direction different from that of the first illumination step while the marking forming portion is viewed from a normal direction; and a second imaging step of imaging the marking in synchronization with the irradiation timing of the second illumination step. A method for reading markings on a metal molded product, comprising:

Images