Printing system and printing method

Abstract

A printing system comprises: a conveying device 2 that conveys a container 10 along a predetermined conveying path; an imaging device 3 that captures an image of the container 10 being conveyed by the conveying device 2; a laser printing device 4 that is disposed at a position downstream of the imaging device 3 in the conveying path and performs laser printing on the container 10 being conveyed by the conveying device 2; and a control device 6, wherein the control device 6 is capable of implementing a rotation angle identification function for identifying the rotation angle of the container 10 on the basis of the image captured by the imaging device 3, and a printing control function for controlling the laser printing device 4 to perform laser printing at a printing position determined on the basis of the rotation angle.

Description

Printing System and Printing Method

[0001] The present invention relates to a printing system and a printing method.

[0002] Products such as beverages and pharmaceuticals are handled in a state of being contained in some kind of container at places such as manufacturing, distribution, and consumption. In recent years, various means for managing each individual of industrially mass-produced products have been studied.

[0003] For example, Japanese Patent Application Laid-Open No. 2020-527891 (Patent Document 1) discloses a beverage container in which a circuit capable of transmitting data is attached to a cap. The beverage container of Patent Document 1 is configured to be able to transmit data only when it is opened. Japanese Patent Application Laid-Open No. 8-72883 (Patent Document 2) discloses a can body characterized in that a code mark related to the manufacture of the can body is printed on the outer periphery of the crimping portion of the can lid. Japanese Patent Application Laid-Open No. 2016-519804 (Patent Document 3) discloses an invention related to a can component on which a matrix bar code is formed, and as a specific embodiment thereof, an aspect in which the matrix bar code is formed on a tab is disclosed.

[0004] Japanese Patent Application Laid-Open No. 2020-527891 (or International Publication No. 2019 / 014450), Japanese Patent Application Laid-Open No. 8-72883, Japanese Patent Application Laid-Open No. 2016-519804 (or International Publication No. 2014 / 150647)

[0005] However, equipping the container with an electronic device as in Patent Document 1 can lead to an increase in cost. This is because, in addition to the electronic device itself being an additional element compared to conventional containers, the work of attaching the electronic device to the container is also additional. In addition, when the electronic device is damaged during the distribution process of the container, the expected function may not be exhibited. Further, the technology of Patent Document 2 only prints information at the manufacturing stage of the can body and is insufficient for identifying each individual of the product. In addition, although Patent Document 3 discloses that marking is to be performed on the tab stock during the residence time or while it is moving during the press process, a specific method for attaching a matrix bar code to a specific position of the tab is not sufficiently disclosed.

[0006] Therefore, there is a need for a printing system and method that can apply individual printing to each individual product. In particular, in order to commercially feasible individual printing on each product, it is necessary to perform printing without interrupting the continuous production of mass-produced products. Containers transported by conveying equipment between processes in continuous production rotate during transport, so even if a printing device is installed on the transport path, the relative position between the printing device and the container will not be constant. For this reason, it has been difficult to apply individual printing to the appropriate position on containers during transport.

[0007] The printing system according to the present invention comprises a transport device for transporting containers along a predetermined transport path, a photographing device for photographing the containers being transported by the transport device, a laser printing device positioned downstream of the photographing device in the transport path and performing laser printing on the containers being transported by the transport device, and a control device, wherein the control device is capable of realizing a rotation angle identification function for identifying the rotation angle of the container based on an image taken by the photographing device, and a printing control function for controlling the laser printing device to perform laser printing at a printing position determined based on the rotation angle.

[0008] The printing method according to the present invention is a printing method for performing laser printing on a container being transported by a transport device, and is characterized by comprising: a photographing step of photographing the container being transported by the transport device; a rotation angle determination step of determining the rotation angle of the container based on the image of the container photographed; and a printing step of performing laser printing at a printing position determined based on the rotation angle.

[0009] In this invention, the rotation angle of each individual container is individually identified, and the printing position is determined based on that rotation angle before laser printing is performed. Therefore, even if the container rotates during transport, printing can be applied to the appropriate position on the container. This makes it possible to apply individual printing to each product.

[0010] Preferred embodiments of the present invention will be described below. However, the scope of the present invention is not limited by the examples of preferred embodiments described below.

[0011] In one embodiment, the printing system according to the present invention may further implement a horizontal position determination function in which the control device determines the horizontal position of the top surface based on the image captured by the imaging device, and it is preferable that the printing position is determined in the printing control function based on the rotation angle and the horizontal position.

[0012] This configuration allows printing to be performed while considering not only the rotational displacement of the container but also the horizontal displacement, thus enabling printing to be performed in a more accurate position.

[0013] In one embodiment, the printing system according to the present invention further includes a detection sensor that detects when the container has moved beyond a predetermined position in the transport path, and it is preferable that the printing control function controls the laser printing apparatus based on the detection signal from the detection sensor.

[0014] This configuration makes it easier to recognize the relative relationship between the container and the laser printing device, allowing for more accurate printing.

[0015] In one embodiment of the printing system according to the present invention, it is preferable that the imaging device is configured to photograph the top surface of the container.

[0016] With this configuration, since the container can be photographed from above, interference between the imaging device and the transport path is less likely to be a problem. Therefore, there is a high degree of flexibility in the placement of the imaging device.

[0017] In one embodiment, the printing system according to the present invention is a can container having a tab on its top surface, and it is preferable that the rotation angle is determined in the rotation angle determination function based on the position of the tab in the image.

[0018] The tab has a distinctive shape and is a relatively large structure on the top surface of the container. Therefore, its position is easy to recognize in captured images, and the rotation angle can be easily determined.

[0019] In one embodiment, the printing system according to the present invention comprises a plurality of laser printing devices, and it is preferable that, in the printing control function, the first laser printing device and the second laser printing device are controlled independently.

[0020] This configuration allows for multiple prints to be applied to the container, making it possible to add more complex information.

[0021] Further features and advantages of the present invention will become clearer through the following description of exemplary and non-limiting embodiments, with reference to the drawings.

[0022] This is a schematic diagram showing the configuration of the printing system according to the embodiment. This is a plan view of the can container according to the embodiment. This is an example of determining the rotation angle and horizontal position of the can container.

[0023] Embodiments of the printing system and printing method according to the present invention will be described with reference to the drawings. Below, an example will be described in which the printing system according to the present invention is applied to a printing system 1 that prints on the top surface of a can container 10 (an example of a container) and a printing method using the same. The can container 10 is a packaged beverage product filled with a beverage.

[0024] [Configuration of the Printing System] The printing system 1 according to this embodiment comprises a transport device 2, a shooting device 3, a laser printing device 4, a detection sensor 5, and a control device 6 (Figure 1). The printing system 1 is a system that prints on can containers 10 while transporting them. The printing system 1 is incorporated as part of a continuous process for the continuous production of packaged beverage products, and in the order of upstream of the continuous process, it is provided in the following order: a filling machine that fills the can body with beverage, a seaming machine (seamer) that seams the can body with a can lid after it has been filled with beverage, and the printing system 1.

[0025] The printing system 1 is generally a system that prints on the top surface 11 of a can container 10 using a laser printing device 4. Since the can container 10 has a cylindrical shape, it rotates during transport by the transport device 2. Therefore, the orientation of each can container 10 when it reaches the laser printing device 4 is different, and the relative relationship between the laser printing device 4 and the printing position is not constant. In this embodiment, the printing position is adjusted based on the image captured by the imaging device 3, so that printing can be performed at a predetermined printing position regardless of the rotation of the can container 10.

[0026] The can container 10 handled in the printing system 1 is a so-called stay-on tab type can container, and has a stay-on tab 12 (an example of a tab) and a score panel 13 on its top surface 11 (Figure 2). The stay-on tab 12 is fixed by a rivet 14 provided in the center of the top surface 11 and extends generally along the radial direction of the top surface 11. The score panel 13 is provided in a position that is roughly in line with the stay-on tab 12 in the plan view.

[0027] In this embodiment, laser printing is performed on a printing area 15 that is set in a part of the margin area of ​​the top surface 11 where the stay-on tab 12 and score panel 13 are not provided. That is, the printing area 15 is set outside the linear area along the diameter of the top surface 11 where the stay-on tab 12 and score panel 13 are provided.

[0028] The conveying device 2 is a device that conveys the can containers 10 in a straight line. The conveying device 2 may be a known conveying device such as a belt conveyor or a roller conveyor. Along the conveying path in which the conveying device 2 conveys the can containers 10, a shooting device 3, a detection sensor 5, and a laser printing device 4 are provided in order from upstream. In at least the section in which these devices are provided, the conveying device 2 is configured to convey the can containers 10 in a line in the conveying direction. The conveying speed of the can containers 10 by the conveying device 2 is not particularly limited, but it may be, for example, about 100 to 200 m per minute.

[0029] The imaging device 3 is a device that photographs the top surface 11 of the can containers 10 being transported by the transport device 2. A known digital camera or the like can be used as the imaging device 3, but it is preferable that it has continuous shooting performance that allows it to photograph each of the multiple can containers 10 being transported continuously by the transport device 2. In other words, the specifications of the imaging device 3 can be determined considering the transport speed of the transport device 2. The imaging device 3 is installed in a downward position above the path through which the transport device 2 transports the can containers 10. The imaging device 3 is electrically connected to the control device 6 (image processing device 61), and the image of the top surface 11 taken by the imaging device 3 is transferred to the control device 6 (image processing device 61).

[0030] The laser printing device 4 is a device that performs laser printing on the top surface 11 of the can container 10 being transported by the transport device 2. As long as the laser printing device 4 is a device capable of laser printing on the material (such as aluminum) that makes up the top surface 11 of the can container 10, any known laser printing device can be used. The laser printing device 4 is installed in a downward position above the transport path through which the transport device 2 transports the can container 10. The laser printing device 4 is also installed downstream of the imaging device 3 in the transport path. The laser printing device 4 is electrically connected to the control device 6 (printing control device 62), and the operation of the laser printing device 4 is controlled by the control device 6 (printing control device 62).

[0031] The form of the design P printed by the laser printing device 4 is not particularly limited and may include, for example, information that enables individual identification of the can container 10, or information related to a promotional campaign for the can container 10. Such information may be printed in any form, such as a barcode, a two-dimensional code, an image, or text.

[0032] The distance between the imaging device 3 and the laser printing device 4 along the transport direction of the transport device 2 is preferably as small as possible, to the extent that the installation and operation of both devices do not interfere with each other, and can be around several tens of centimeters (for example, around 20 centimeters). By making the distance between the imaging device 3 and the laser printing device 4 as small as possible, the rotation of the can container 10 from the time it is photographed by the imaging device 3 until it reaches the laser printing device 4 can be virtually ignored, so that the adjustment of the printing position based on the image of the top surface 11 taken by the imaging device 3 works effectively.

[0033] The detection sensor 5 is a sensor that detects when the can container 10 has passed a predetermined position on the transport path, and may be, for example, a photoelectric sensor or an infrared sensor. In this embodiment, a straight detection line 51 intersecting the transport path is set at a position immediately in front of the laser printing device 4 on the transport path of the transport device 2, and the detection sensor 5 is configured to detect when the leading edge of the transported can container 10 crosses the detection line 51. Therefore, the detection sensor 5 is configured to emit light (visible light, infrared light, etc.) corresponding to the detection method of the detection sensor 5 toward the detection line 51. The detection sensor 5 is electrically connected to the control device 6 (printing control device 62), and the detection signal from the detection sensor 5 is input to the control device 6 (printing control device 62).

[0034] The control device 6 is a control device capable of at least image processing based on images captured by the imaging device 3, controlling the laser printing device 4, and receiving detection signals from the detection sensor 5. It is not prevented from being configured to perform other functions (for example, controlling the transport device 2).

[0035] The number of components constituting the control device 6 may be one or multiple. In this embodiment, the control device 6 is described as having an image processing device 61 that performs image processing and a print control device 62 that controls the laser printing device 4. The image processing device 61 and the print control device 62 are electrically connected and can communicate with each other.

[0036] The image processing device 61 is a device that performs image processing based on the image captured by the imaging device 3, and can be, for example, a well-known computer. Therefore, the image processing device 61 may have common computer components such as a processing unit such as a CPU, a storage device such as a hard disk drive, a display device such as a liquid crystal display, and input devices such as a keyboard and mouse. The image processing device 61 is electrically connected to the imaging device 3, and the image of the top surface 11 captured by the imaging device 3 is input to the image processing device 61.

[0037] The print control device 62 is a device that controls the laser printing device 4, and may be, for example, a programmable logic controller (PLC). The print control device 62 is electrically connected to the laser printing device 4 and transmits and receives signals for controlling the laser printing device 4. In addition, the detection signal from the detection sensor 5 is input to the print control device 62.

[0038] [Functions of the Control Device (Printing Method)] Next, the rotation angle identification function, horizontal position identification function, and print control function of the control device 6 will be described. Since printing by the printing system 1 is performed when each function of the control device 6 is realized, the following description also describes the printing method according to this embodiment.

[0039] (1) Rotation angle determination function The rotation angle determination function is a function that determines the rotation angle of the can container 10 (top surface 11) based on the image of the top surface 11 taken by the imaging device 3. The rotation angle determination function is realized by the image processing device 61.

[0040] First, the image processing device 61 performs a process to enhance the contour of the image of the top surface 11. Next, it identifies the portion of the stay-on tab 12 in the contour-enhanced image. Finally, it compares the direction in which the stay-on tab 12 extends in the image to be processed with the direction in which the stay-on tab 12 extends in a reference image previously stored in the image processing device 61 to determine the rotation angle of the can container 10 (top surface 11) in the image to be processed.

[0041] For example, an image of the top surface 11 in the orientation shown in Figure 2 is used as the reference image, and the rotation angle is defined with the direction in which the stayon tab 12 extends in the reference image (to the right in the Figure 2 plane) as the starting line. In the example shown in Figure 3, the stayon tab 12 extends in the downward right direction, and the rotation angle θ is determined as the angle that the direction in which the stayon tab 12 extends makes with the starting line. The determined rotation angle θ is input from the image processing device 61 to the print control device 62.

[0042] (2) Horizontal position determination function The horizontal position determination function is a function that determines the horizontal position of the can container 10 (top surface 11) based on the image of the top surface 11 captured by the imaging device 3. The horizontal position determination function is realized by the image processing device 61.

[0043] In the horizontal position specifying function, similar to the rotation angle specifying function, an image subjected to a process of emphasizing the contour is used. Since such a process is performed in the rotation angle specifying function, the same image may be used. The image processing apparatus 61 specifies the position of the station tab 12 in the image with the emphasized contour. Next, the position of the station tab 12 in the image to be processed is compared with the position of the station tab 12 in the aforementioned reference image, and the horizontal position of the can container 10 (top surface 11) in the image to be processed is specified.

[0044] For example, taking the image of the top surface 11 in the posture shown in FIG. 2 as a reference image, an XY coordinate system is set with the center of the top surface 11 in the reference image (i.e., the position of the rivet 14) as the origin. The X-axis is the conveyance direction by the conveyance apparatus 2 and extends rightward from the center of the paper surface of FIG. 2. The Y-axis is a direction orthogonal to the conveyance direction and extends upward from the center of the paper surface of FIG. 2. In the example shown in FIG. 3, the position of the station tab 12 is shifted upward and rightward from the origin of the XY coordinate system compared to the reference image, and the horizontal position of the top surface 11 is specified as the displacement amount (X, Y) of the station tab 12. The specified displacement amount (X, Y) is input from the image processing apparatus 61 to the printing control apparatus 62.

[0045] (3) Printing control function The printing control function is a function of controlling the laser printing apparatus 4 so that laser printing is performed with the printing area 15 of the top surface 11 as the printing position. The printing control function is realized by the printing control apparatus 62.

[0046] The printing control apparatus 62 stores in advance a control amount (hereinafter referred to as a reference control amount) to be transmitted in order to control the laser printing apparatus 4 so that laser printing is performed with the printing area 15 as the printing position when the can container 10 enters in the same posture as the reference image at the position where printing by the laser printing apparatus 4 is performed. The control amount includes parameters for controlling, for example, the irradiation direction, irradiation time, irradiation intensity, etc. of the laser. The control amount for performing laser printing on each can container 10 is determined by adding corrections based on the rotation angle θ and the displacement amount (X, Y) to the reference control amount.

[0047] Also, the timing when the laser printing device 4 actually operates is determined based on the detection signal of the detection sensor 5. Since the detection sensor 5 detects that the leading end of the conveyed can container 10 has crossed the detection line 51 in the conveyance direction, based on the timing of this detection, the timing when the can container 10 enters the position where printing is performed by the laser printing device 4 can be specified.

[0048] With the above rotation angle specifying function, horizontal position specifying function, and printing control function, laser printing can be performed with a predetermined printing area 15 as the printing position regardless of the rotation of the can container 10.

[0049] [Other Embodiments] Finally, other embodiments of the printing system and printing method according to the present invention will be described. Note that the configurations disclosed in each of the following embodiments can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction.

[0050] In the above embodiment, the configuration in which the imaging device 3 images the top surface 11 of the can container 10 has been described as an example. However, in the present invention, the imaging device only needs to be able to image any part of the container being conveyed by the conveying device, and that part is not limited to the top surface. For example, for a container having a characteristic part such as a mark or a label on the shoulder or the body, by providing the imaging device so that the characteristic part is included in the imaging range, the rotation angle of the container can be determined based on the position of the characteristic part in the image. Note that the number and arrangement of the imaging devices can be appropriately determined in consideration of the conveying device and the form of the container so that an image capable of determining at least the rotation angle of the container can be obtained.

[0051] In the above embodiment, a configuration in which there is one laser printing device 4 was described as an example. However, the number of laser printing devices is not limited in the present invention. Furthermore, when the present invention comprises multiple laser printing devices, the first laser printing device and the second laser printing device can be controlled separately. For example, it is possible to have the first laser printing device and the second laser printing device print different information, print on different locations on the top surface of the container, or have only one printing device that can perform appropriate printing on the printing area considering the rotation angle of the container perform printing. In addition, when the present invention comprises multiple laser printing devices, the number of imaging devices may be the same as or different from the number of laser printing devices.

[0052] In the above embodiment, a configuration in which the laser printing device 4 performs laser printing on the top surface 11 of the can container 10 was described as an example. However, in the present invention, the position where laser printing is performed is not limited to the top surface of the container. Furthermore, in the above embodiment, when laser printing is performed on the top surface of the container, a configuration in which the printing area 15 is set in a part of the blank area of ​​the top surface 11 where the stay-on tab 12 and score panel 13 are not provided was illustrated, but this is also merely an example. As other configurations for providing a printing area on the top surface of the container, the printing area may be provided on the stay-on tab or score panel in a can container, or on the lid in a resin container or glass container. The number and arrangement of laser printing devices can be appropriately determined considering the printing area to be set on the container.

[0053] In the above embodiment, a configuration in which the printing system 1 is equipped with a detection sensor 5 was described as an example. However, in the present invention, the presence or absence of a detection sensor is optional. In the case of a configuration without a detection sensor, for example, the timing at which the laser printing device 4 actually operates can be controlled based on the timing of the image capture by the imaging device 3.

[0054] In the above embodiment, a configuration in which a stay-on tab type can container 10 is used as the printing target was described as an example. However, the container to be printed on in the present invention is not limited and can be a plastic bottle, can, bottle, box, etc.

[0055] In the above embodiment, a configuration was described as one in which the rotation angle of the can container 10 (top surface 11) is determined based on the position of the stay-on tab 12. However, in the present invention, the specific method for determining the rotation angle of the container is not limited. For example, the rotation angle can be determined based on the position of any element installed, attached, or printed on the container, such as a score panel, rivets, braille markings, a logo, or printed materials such as labels or tags. Similarly, the determination of the horizontal position of the container is not limited to the method based on the position of the stay-on tab 12 in the above embodiment, but can be based on the position of any element, such as the container's contour, score panel, rivets, braille markings, a logo, or printed materials such as labels or tags.

[0056] In the above embodiment, a configuration in which a horizontal position identification function is realized was described as an example, but in the present invention, the realization of a horizontal position identification function is optional. Also, in the above embodiment, a configuration in which the horizontal position of the can container 10 (top surface 11) is identified as the displacement amount (X, Y) of the stayon tab 12 was illustrated, but for example, only the Y coordinate may be identified. Since the position of containers transported by a transport device may vary from one individual to another in the direction perpendicular to the transport direction, identifying the Y coordinate of the container, i.e., the horizontal position in the direction perpendicular to the transport direction, makes it easier to achieve printing at an accurate position. On the other hand, since the X coordinate is the horizontal position along the transport direction, the position in that direction can be corrected by other methods such as providing a detection sensor as in this embodiment.

[0057] With regard to other configurations, the embodiments disclosed herein are illustrative in all respects, and it should be understood that the scope of the present invention is not limited thereto. Those skilled in the art will readily understand that modifications can be made as appropriate without departing from the spirit of the invention. Therefore, other embodiments modified without departing from the spirit of the invention are naturally included within the scope of the present invention.

[0058] This invention can be used, for example, for laser printing on canned containers.

[0059] 1: Printing system 2: Transport device 3: Imaging device 4: Laser printing device 5: Detection sensor 51: Detection line 6: Control device 61: Image processing device 62: Printing control device 10: Can container 11: Top surface 12: Stay-on tab 13: Score panel 14: Rivet 15: Printing area

Claims

1. A printing system comprising: a transport device for transporting containers along a predetermined transport path; a photographing device for photographing the containers being transported by the transport device; a laser printing device positioned downstream of the photographing device in the transport path and performing laser printing on the containers being transported by the transport device; and a control device, wherein the control device is capable of realizing: a rotation angle identification function for identifying the rotation angle of the container based on an image taken by the photographing device; and a printing control function for controlling the laser printing device to perform laser printing at a printing position determined based on the rotation angle.

2. The printing system according to claim 1, wherein the control device can further implement a horizontal positioning function that identifies the horizontal position of the container based on an image captured by the imaging device, and the printing control function determines the printing position based on the rotation angle and the horizontal position.

3. The printing system according to claim 1, further comprising a detection sensor for detecting when the container has moved beyond a predetermined position in the transport path, wherein the printing control function controls the laser printing apparatus based on the detection signal of the detection sensor.

4. The printing system according to claim 1, wherein the imaging device is configured to photograph the top surface of the container.

5. The printing system according to claim 4, wherein the container is a can container having a tab on its top surface, and the rotation angle is determined in the rotation angle determination function based on the position of the tab in the image.

6. The printing system according to claim 1, comprising a plurality of the laser printing devices, wherein the first laser printing device and the second laser printing device are each controlled independently in the printing control function.

7. A printing method for laser printing on a container being transported by a transport device, comprising: a photographing step of photographing the container being transported by the transport device; a rotation angle determination step of determining the rotation angle of the container based on the image of the container photographed; and a printing step of performing laser printing on a printing position determined based on the rotation angle.

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