Barrel printing method and barrel printing system

Abstract

To provide a barrel printing method and a barrel printing system capable of performing a printing of high discriminability on an outside surface of a returnable metallic barrel without using a plastic film such as label, by using an existing barreling system.SOLUTION: A barrel printing system 10 is a barrel printing system which performs printing on an outside surface of a barrel, in a barreling system 1 for charging a content into a returnable barrel 100. The barreling system 1 includes: a conveyance device 5 which conveys the barrel along a prescribed conveyance path 6; and an inside washing device 3 which washes an inner surface of the barrel conveyed by the conveyance device 5 to perform sterilization with steam of 100°C or higher. The barrel printing system 10 includes a printing device 11 which attaches ink onto the outer surface of the barrel, on an upstream of the conveyance device 5 from the inside washing device 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a barrel printing method and system. [Background technology]

[0002] Returnable barrels are known as metal barrels for storing beverages such as beer. They are distributed on the market, and once the contents are consumed, they are collected and reused. Quality control information consisting of letters, numbers, or symbols, such as lot numbers, is printed on the outer surface of returnable barrels. After collection, the printing is removed when the outer surface of the barrel is washed, and information about the newly filled contents is printed instead (see, for example, Patent Document 1). Patent Document 1 proposes a barrel printing device that prevents the printing from chipping or bleeding even if the barrel is not sufficiently dried after washing, and describes the printing format as letters, numbers, or symbols. Plastic labels are also sometimes attached to the surface of barrels (see, for example, Patent Document 2).

[0003] A technique has been proposed for applying highly decorative letters, designs, or patterns to the outer surface of a returnable container (see, for example, Patent Document 3). Patent Document 3 proposes a technique in which an inkjet printer is used to draw a pattern or the like on the outer surface of a returnable container using a first ink that can be removed with a solvent, and after hardening this pattern or the like, letters or the like are overlaid on the pattern made with the hardened first ink using a second ink.

[0004] When printing on the outer surface of a three-dimensional object of revolution, such as a cylinder, a method is generally used in which a printed image is formed while the three-dimensional object of revolution is rotating (see, for example, Patent Document 4). In this case, if the outer surface of the container is made of a non-absorbent material, such as metal, that does not absorb the printing ink, the ink may flow and smear during the rotation of the three-dimensional object of revolution. To solve this problem, a method has been proposed in which a clear printed image is printed on the non-ink-absorbent surface of a cylindrical container using inkjet printing ink with a special composition (see, for example, Patent Document 5). Patent Document 5 discloses a method in which the non-absorbent surface of a cylindrical container is adjusted to a temperature of 25 to 100°C, then inkjet printing is performed using inkjet printing ink with a special composition, and then a finishing varnish is applied. The method also discloses a method for controlling the temperature of the non-absorbent surface, such as indirectly heating the cylindrical container by heating the mandrel that supports and fixes the cylindrical container, or directly heating the non-absorbent surface of the cylindrical container itself using hot air, high-frequency heating, or infrared heating. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-131858 [Patent Document 2] Japanese Patent Publication No. 2022-51477 [Patent Document 3] Patent Publication No. 2021-107255 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-136217 [Patent Document 5] Japanese Patent Application Laid-Open No. 2013-177571 Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 describes letters, numbers, or symbols (hereinafter, letters, numbers, or symbols may be collectively referred to as letters, etc.) as the form of printing, but there is a demand for not only letters, but also decorative designs including images to be displayed on the outer surface of the barrel. Conventionally, such decorative designs have been printed on plastic film, such as labels or stretch labels as in Patent Document 2, and the plastic film has been attached or wrapped around the outer surface of the barrel to display it. However, with the recent promotion of reducing the amount of plastic used, there is a demand for decorative designs to be printed on the outer surface of the barrel without using plastic film.

[0007] Furthermore, with labels such as those in Patent Document 2, the printing design is fixed, and adding a new design including a one-dimensional or two-dimensional code containing information requires the production of a new plate, which is very costly. There is also the problem that adding different information for each barrel is not possible with plate printing.

[0008] Patent Document 3 proposes a method for printing highly decorative letters, designs, or patterns on the outer surface of returnable containers, but does not consider a method for in-line printing in a keg system. A method for forming a printed image while rotating a rotating three-dimensional object, as in Patent Document 4, may be applicable to in-line printing, but as mentioned above, there is the problem of ink flow during rotation, and it is necessary to use inkjet printing ink with a special composition, as in Patent Document 5. The ink in Patent Document 5 is intended for seamless cans, which are one-way containers, and therefore is not intended to remove the printing by washing after collection, as is the case with returnable kegs, and therefore cannot be applied to printing on returnable kegs.

[0009] Furthermore, printing a design tends to require a larger amount of ink than printing letters, numbers, or symbols as in Patent Document 1. The greater the amount of ink used, the longer the drying time required to fix the ink, making it a challenge to dry the ink within the limited time it takes to pass through the kegging system. While one technique for quickly drying ink uses high-temperature hot air, this technique has the problem of causing color unevenness and damaging the aesthetic appearance. Furthermore, this requires the introduction of new equipment to generate high-temperature hot air, which necessitates changes to the factory layout and increases production costs. Due to these circumstances, no technology has been developed to print a design on the outer surface of a keg inline in a kegging system.

[0010] Currently, returnable barrels use plastic labels such as stretch labels to identify the product during the distribution process. There is a demand to reduce the amount of plastic used and provide an environmentally friendly product by replacing plastic labels with printing that uses ink directly on the barrel surface (hereinafter, printing that uses ink directly on the barrel surface will also be referred to as direct printing). To realize direct printing on returnable barrels, it is necessary to ensure the same level of product identification and distribution suitability as current plastic labels, as well as ensure the reusability of the barrels as returnable containers.

[0011] Direct printing on barrels requires features such as suppressing color unevenness and ensuring product identifiability even when rubbed during handling to maintain product distinctiveness. To achieve these features, it is important to dry the ink evenly after direct printing to prevent color unevenness or ink dripping. When printing on paper, the paper absorbs the ink, fixing the printed design, and high-temperature hot air allows the ink to dry evenly. On the other hand, direct printing on barrels has issues with ink absorption, resulting in poor fixation of the printed design. Furthermore, drying the ink with high-temperature hot air can result in color unevenness and prolonged drying times. Furthermore, if the temperature of the barrel when the ink is applied is higher than the boiling point of the solvent, such as water or organic solvent, contained in the ink, the solvent instantly evaporates from the barrel's surface. This prevents ink droplets from spreading, creating gaps between the ink droplets, exposing the barrel's surface and obscuring the color, reducing distinctiveness. Furthermore, because barrels are returnable containers, alkaline cleaning during the manufacturing process is required to remove ink components to maintain reusability.

[0012] The present disclosure aims to provide a barrel printing method and barrel printing system that can apply highly identifiable printing to the outer surface of returnable metal barrels without using plastic films such as labels, by utilizing an existing barreling system. [Means for solving the problem]

[0013] The barrel printing method of the present invention is a barrel printing method for printing on the outer surface of a returnable barrel in a barrel filling system that transports the barrel along a predetermined transport path and fills the barrel with contents, wherein the barrel filling method in the barrel filling system includes a steam sterilization process in which steam at 100°C or higher is introduced into the internal space of the barrel, and the barrel printing method is characterized in that it includes an ink application process that is carried out before the steam sterilization process in which ink is applied to the outer surface of the barrel, and a main drying process that, after the steam sterilization process, uses the temperature rise of the barrel in the steam sterilization process to completely dry the ink that has been applied to the outer surface of the barrel in the ink application process.

[0014] In the barrel printing method according to the present invention, the barrel filling method preferably further includes an external washing step of washing the external surface of the barrel with an external washing liquid before the steam sterilization step, and the ink application step is preferably performed after the external washing step. Dirt and printed ink adhering to the external surface of barrels returned from the market can be removed to make the surface easier to print on.

[0015] The barrel printing method according to the present invention preferably further includes a draining step of removing the external washing liquid adhering to the outer surface of the barrel after the external washing step and before the ink application step, thereby preventing chipping or bleeding of the print.

[0016] In the barrel printing method according to the present invention, the exterior washing step preferably includes a finishing washing step in which the exterior washing liquid is a finishing liquid at 40 to 100°C. The barrel printing method preferably further includes a pre-drying step, which is performed after the ink application step and before the steam sterilization step, in which the ink applied to the exterior surface of the barrel in the ink application step is pre-dried by increasing the temperature of the barrel in the finishing washing step. This allows the ink applied to the exterior surface of the barrel to dry at a more appropriate drying rate. As a result, the ink droplets are spread out, reducing the gaps between the ink droplets and preventing ink dripping.

[0017] In the barrel printing method according to the present invention, the ink application step is preferably carried out while the temperature of the outer surface of the barrel is maintained at 40 to 100°C. This allows the ink applied to the outer surface of the barrel to dry at a more appropriate drying rate. As a result, the ink droplets are wetted and spread, reducing the gaps between the ink droplets and preventing ink dripping.

[0018] In the barrel printing method according to the present invention, the time from the end of the ink application process to the start of the steam sterilization process is preferably shorter than the time from the end of the external washing process to the start of the ink application process. This allows the ink to be fixed by main drying before it bleeds. Furthermore, this also prevents the print from bleeding due to dripping of water remaining on the barrel.

[0019] In the barrel printing method according to the present invention, the ink is preferably a water-based ink. This makes it easier to remove the ink by alkaline cleaning than when oil-based ink is used. In addition, printing can be performed more safely.

[0020] In the barrel printing method according to the present invention, the barrel filling method includes an embodiment further including a filling step of filling the contents into the barrel after the steam sterilization step.

[0021] The barrel printing system of the present invention is a barrel printing system that prints on the outer surface of a returnable barrel in a barrel filling system that fills contents into the barrel, and is characterized in that the barrel filling system comprises a conveying device that conveys the barrel along a predetermined conveying path, and an internal cleaning device that cleans the inner surface of the barrel conveyed by the conveying device with an internal cleaning liquid and sterilizes it with steam at 100°C or higher, and the barrel printing system comprises a printing device that applies ink to the outer surface of the barrel upstream of the internal cleaning device on the conveying path.

[0022] The barreling system according to the present invention preferably further comprises an external washing device located upstream of the internal washing device along the transport path for washing the external surfaces of the barrels with an external washing liquid, and the printing device applies the ink to the external surfaces of the barrels downstream of the external washing device along the transport path. This removes dirt and printed ink from the external surfaces of barrels returned from the market, making the surfaces easier to print on.

[0023] The barrel printing system according to the present invention preferably further includes a draining device located downstream of the external washing device along the conveying path and upstream of the printing device along the conveying path, for removing the external washing liquid adhering to the outer surface of the barrels after washing in the external washing device. This can prevent chipping or bleeding of the print.

[0024] In the barrel printing system according to the present invention, the external washing device preferably includes a finishing liquid supply device that supplies finishing liquid at a temperature of 40 to 100°C. This allows the ink adhering to the outer surface of the barrel to dry at a more appropriate drying rate. As a result, the ink droplets are spread out, reducing the gaps between the ink droplets and preventing ink dripping. [Effects of the Invention]

[0025] According to the present disclosure, it is possible to provide a barrel printing method and barrel printing system that can apply highly identifiable printing to the outer surface of returnable metal barrels by utilizing an existing barreling system without using plastic films such as labels. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic configuration diagram illustrating an example of a barrel printing system according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram showing an example of a returnable barrel. [Figure 3] FIG. 2 is a schematic diagram for explaining a lifting and rotating device. [Figure 4] These are the results of an evaluation to confirm the relationship between the temperature of the outer surface of the barrel and the drying of the ink, and show the results when the temperature of the outer surface of the barrel was 20°C, 30°C, and 40°C. [Figure 5] These are the results of an evaluation to confirm the relationship between the temperature of the outer surface of the barrel and the drying of the ink, and show the results when the temperature of the outer surface of the barrel was 50°C, 90°C, and 120°C. [Figure 6] These are the results of an evaluation to confirm the relationship between the temperature of the barrel's outer surface and the wetting and spreading of ink. Images are shown at barrel outer surface temperatures of 20°C, 30°C, and 40°C. [Figure 7] These are the results of an evaluation to confirm the relationship between the temperature of the barrel's outer surface and the wetting and spreading of ink. Images are shown at barrel outer surface temperatures of 50°C, 90°C, and 120°C. DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention will be described with reference to the accompanying drawings, but the present invention is not limited to these descriptions. Various modifications may be made to the embodiments as long as the effects of the present invention are achieved.

[0028] First, a barrel printing system according to this embodiment will be described. Fig. 1 is a schematic diagram showing an example of a barrel printing system according to this embodiment. The barrel printing system 10 according to this embodiment is a barrel printing system that prints on the outer surface of a returnable barrel 100 (for example, as shown in Fig. 2) in a kegging system 1 that fills contents into the barrel. The kegging system 1 includes a conveying device 5 that conveys the barrel along a predetermined conveying path 6, and an interior washing device 3 that cleans the inner surface of the barrel conveyed by the conveying device 5 with an interior washing liquid and sterilizes it with steam at 100°C or higher. The barrel printing system 10 includes a printing device 11 that applies ink to the outer surface of the barrel upstream of the interior washing device 3 on the conveying path 5.

[0029] FIG. 2 is a schematic diagram showing an example of a returnable barrel. The barrel 100 has a body 101 for accommodating the contents, and an upper skirt 102 and a lower skirt 103 connected to the top and bottom of the body 101. A nozzle 101a is provided at the upper end of the body 101, and the contents are filled and poured through the nozzle 101a. The upper and lower skirts 102, 103 are provided so as to extend the outer periphery of the body 101 in the upper and lower directions, respectively. The upper skirt 102 is provided with a handle 104 that can be grasped by an operator when transporting the barrel 100. The contents are not particularly limited, but may be, for example, beer, happoshu, or other sparkling alcoholic beverages. The capacity of the barrel 100 is typically 7 to 20 L, but is not particularly limited in the present invention.

[0030] The outer surface of the keg 100 that constitutes the printing area includes, for example, the side of the barrel 101, the side of the upper skirt 102, and the side of the lower skirt 103. The printing area may be provided on only a portion of the circumference of the barrel's side, or may be provided intermittently or continuously over the entire circumference of the barrel's side. For example, it is preferable that printing is performed continuously or intermittently over the entire circumference of the side of the barrel 101. The printed content may consist of only text, only images, or both text and images. For example, Figure 2 shows an example in which the product name "Kirin Lager Beer" (Kirin Lager is a registered trademark), the variety "beer," the volume "20L," and a two-dimensional code are printed on the side of the barrel 101. However, the present invention is not limited to this. The printing area may be limited to the side of the body 101, or may extend to the side of the body 101 as well as the side of the upper skirt 102 and / or the side of the lower skirt 103, or may be limited to the side of the upper skirt 102 or the side of the lower skirt 103. While FIG. 2 shows an image processed to grayscale, a more accurate representation is possible using a color image before processing to grayscale. For example, full color printing may be used, with the text in red and the image in black.

[0031] 2 shows a metal barrel as an example, but the present invention is not limited to this and the barrel may be made of resin, or the barrel may have a metal body 101 and rubber upper skirt 102 and lower skirt 103. In consideration of heat resistance, a metal barrel is more preferable.

[0032] The kegging system 1 is a kegging line that cleans and sterilizes returnable kegs collected from stores and other markets, and then refills them with their contents.

[0033] The internal washing device 3 is a device for cleaning and sterilizing the internal surface of a barrel. For example, an internal washing liquid is introduced into the barrel to clean the internal surface of the barrel, and then steam is introduced into the barrel to sterilize the internal surface of the barrel. The internal washing liquid and steam are introduced through the nozzle part 101a of the barrel (shown in FIG. 2). The internal washing device 3 may be a rotary type internal washing device that cleans and sterilizes the barrel while moving it along a circular conveying path 6, as shown in FIG. 1, or it may be a lane type internal washing device with a linear conveying path.

[0034] The barreling system 1 preferably further comprises an external washing device 2, which is located upstream of the internal washing device 3 on the conveying path 6 and washes the external surfaces of the barrels with external washing liquid. The external washing device 2 is a device that removes dirt from the external surfaces of the barrels and removes ink and the like printed on the external surfaces, and for example, sprays external washing liquid onto the barrels while they are being conveyed by the conveying device 5 to wash them. The external washing device 2 may be an inverted type that conveys the barrels with the nozzle 101a (shown in Figure 2) facing downwards, or an upright type that conveys the barrels with the nozzle 101a facing upwards.

[0035] In the barrel printing system according to this embodiment, the external washing device 2 preferably has at least a finishing liquid supply device that supplies finishing liquid at 40 to 100°C. The finishing liquid supply device is a device that sprays finishing liquid heated to a predetermined temperature onto the outer surface of the barrel. The finishing liquid supply device may also have a finishing liquid heating device. By having the external washing device 2 have a finishing liquid supply device, the ink applied to the outer surface of the barrel by the printing device 11 (described later) can be dried at a more appropriate drying speed. As a result, the ink droplets can be spread out to reduce the gaps between the ink droplets, while preventing ink dripping.

[0036] The barrel filling system 1 may also include a configuration further including a filling device 4 that fills the contents into barrels, downstream of the internal cleaning device 3 on the conveying path 6. As shown in Figure 1, the filling device 4 may be a rotary type filling device that continuously fills barrels while moving them along the circular conveying path 6, or a lane type filling device that has a linear conveying path and intermittently fills them.

[0037] The conveying device 5 is a device, such as a belt conveyor, that moves the barrels along the conveying path 6. In this embodiment, the conveying device 5 includes a conveying device 5a located upstream of the conveying path 6 of the external washing device 2, a conveying device 5b located between the external washing device 2 and the internal washing device 3, a conveying device 5c located between the internal washing device 3 and the filling device 4, and a conveying device 5d located downstream of the conveying path 6 of the filling device 4.

[0038] The predetermined conveying path 6 is a path along which the barrels are moved by the conveying device 5. Taking the barreling system 1 shown in Figure 1 as an example, the predetermined conveying path 6 includes, for example, a path for guiding the barrels to the external washing device 2, a path for passing the barrels through the external washing device 2, a path for guiding the barrels coming out of the external washing device 2 to the internal washing device 3, a path for passing the barrels through the internal washing device 3, a path for guiding the barrels coming out of the internal washing device 3 to the filling device 4, a path for passing the barrels through the filling device 4, and a path for guiding the barrels coming out of the filling device 4 to, for example, an inspection area.

[0039] In the barreling system 1, barrels are transported by the conveying device 5a to the exterior washing device 2, where their exterior surfaces are washed to remove ink and other materials printed on the exterior surfaces, and then transported by the conveying device 5b to the interior washing device 3. Next, the barrels, whose interior surfaces have been washed and sterilized in the interior washing device 3, are transported by the conveying device 5c to the filling device 4. At this time, the barrels are discharged from the interior washing device 3 with steam introduced therein, so steam sterilization continues until they reach the filling device 4, where they are transported by the conveying device 5c. After arriving at the filling device 4, the barrels are filled with the contents, transported by the conveying device 5d, and after inspection, loaded onto a pallet or the like. In the barreling system 1, multiple barrels are transported continuously at predetermined intervals by the conveying device 5, undergo exterior and interior washing, and are then filled with the contents.

[0040] The barrel printing system 10 is incorporated into an existing barreling system 1 and is a system for printing on the outer surface of the barrel.

[0041] Typically, when printing on ink-permeable substrates such as paper, the ink is dried using a hot air dryer. In this case, the ink is absorbed into the paper, fixing the printed design. Subsequent drying with high-temperature hot air allows the ink to dry evenly. On the other hand, when printing directly onto barrels, the substrate is metal, so the ink is not absorbed and the printed design is not fixed. For this reason, drying with a hot air dryer poses challenges, such as the ink being washed away by the hot air, resulting in uneven color and prolonged drying times. Furthermore, when printing, ink droplets wet and spread across the substrate surface, and when adjacent ink droplets come into contact with each other, the substrate surface is covered with ink, resulting in clearer prints and enhanced distinctiveness. However, when the substrate temperature to which the ink is applied is high, around 100°C, the ink solvent evaporates instantly, preventing the ink droplets from wetting and spreading across the substrate, resulting in gaps between the ink droplets. This can leave exposed areas of the substrate in the printed design, potentially obscuring the print and reducing distinctiveness. After steam sterilization in the internal washing device 3, the temperature of the barrel rises. For example, the temperature of the barrel's outer surface reaches a high temperature of around 100°C. Therefore, if ink is applied downstream of the internal washing device 3 on the conveying path 6, the ink droplets may not wet and spread, resulting in reduced identifiability. The inventors discovered that by applying ink to the barrel's outer surface before steam sterilization in the internal washing device 3, the ink droplets can be adequately wetted and spread on the barrel's outer surface. Then, by utilizing the temperature increase caused by steam sterilization at 100°C or higher in the internal washing device 3, the ink solvent can be quickly evaporated. This allows the ink to be uniformly dried and fixed, resulting in highly identifiable printing, without the need for an additional dedicated drying device. This led to the completion of the present invention. Specifically, in the barrel printing system 10 according to this embodiment, the printing device 11 is positioned within the barreling system 1 so that ink can be applied to the barrel's outer surface upstream of the internal washing device 3 on the conveying path 5. As a result, the ink applied to the barrel's outer surface dries as the temperature of the barrel increases due to steam sterilization in the internal washing device 3. Therefore, there is no need to provide a dedicated drying device for drying the ink, and the barrel printing system 10 can be incorporated into the existing barreling system 1 without changing the layout thereof.

[0042] The printing device 11 is not particularly limited as long as it can adhere ink to the outer surface of the barrel, and may be, for example, an inkjet printer, a transfer printer, a brush coating device, or a spray coating device. Of these, the printing device 11 is preferably an inkjet printer, and more preferably a drop-on-demand full-color inkjet printer. This allows for high flexibility, such as small-lot, high-mix production and variable printing. In addition, the barrel printing system 10 can be easily incorporated into the existing barreling system 1 simply by installing the inkjet printer along the conveyance path 6 of the barreling system 1.

[0043] The barrel printing system 10 according to this embodiment includes a form of printing directly on the outer surface of a barrel. Here, direct printing means that ink is applied to the outer surface of the barrel, rather than to a label such as a shrink label, and then dried and fixed.

[0044] Liquids, viscous substances, or solids for application to objects include those called "ink" and those called "paint." So-called "ink" is primarily used for printing (drawing) text or images on objects, and is often prepared for use with printing machines such as inkjet printers and transfer printers. So-called "paint" is primarily used for protecting or beautifying objects or for imparting functionality, and is often prepared for use in painting, such as brush painting or spray painting. In this embodiment, ink is a concept that encompasses both so-called "ink" and so-called "paint."

[0045] The ink is either an aqueous ink containing water as the primary solvent or an oil-based ink containing an organic solvent as the primary solvent. Of these, the ink is preferably an aqueous ink. When printing a large area, oil-based ink requires a large amount of organic solvent, which may exceed the allowable consumption limit. However, compared to oil-based ink, aqueous ink has less impact on human health and the environment and is less flammable, making it safer. Furthermore, aqueous ink is alkali-soluble and therefore easier to remove by cleaning with the external cleaning device 2 than oil-based ink, achieving high cleanability. When the ink is oil-based, the barrel printing system 10 preferably has a local exhaust ventilation system.

[0046] It is preferable that the part of the printing device 11 that supplies ink to the outer surface of the barrel is arranged along the conveying device 5b upstream of the internal washing device 3. Taking an inkjet printer as an example, the part that supplies ink to the outer surface of the barrel is the inkjet head. In this case, it is sufficient that the inkjet head of the inkjet printer is arranged along the conveying device 5b upstream of the internal washing device 3, and the position where the main body of the inkjet printer is arranged is not particularly limited.

[0047] The printing may be one layer only, or two or more layers. When the printing is one layer only, the ink is, for example, a character image ink for forming a character image layer including characters, images, etc. When the printing is two or more layers, the ink includes, in addition to the character image ink, for example, a primer ink for forming a primer layer provided between the character image layer and the outer surface of the barrel and / or an overcoat ink for forming an overcoat layer provided on the character image layer.

[0048] When printing is performed on only one layer, the barrel printing system 10 includes a character image printing device 11 that prints character image ink. When printing is performed on two or more layers, the barrel printing system 10 includes, as the printing device 11, a primer printing device that prints primer ink and / or an overcoat printing device that prints overcoat ink, in addition to the character image printing device. The character image printing device, primer printing device, and overcoat printing device may be printing devices of the same type or different types. For example, when the character image printing device, primer printing device, and overcoat printing device are all inkjet printers, one inkjet printer may have multiple inkjet heads, and the character image printing device, primer printing device, and overcoat printing device may be inkjet heads mounted on the same inkjet printer, or each printing device may be a separate inkjet printer. The combination of the character image printing device, primer printing device, and overcoat printing device is not particularly limited. For example, the primer printing device and overcoat printing device may be brush coating devices or spray devices, and the character image printing device may be an inkjet printer. The character image printing device is preferably a full-color inkjet printer, and more preferably has at least C (cyan), M (magenta), Y (yellow), and K (black) heads. Furthermore, when the printing device 11 is a character image printing device and a primer printing device, it is preferable that the printing device 11 applies ink to the outer surface of the barrel in the order of the primer printing device and the character image printing device. When the printing device 11 is a character image printing device and an overcoat printing device, it is preferable that the printing device 11 applies ink to the outer surface of the barrel in the order of the character image printing device and the overcoat printing device. When the printing device 11 is a character image printing device, a primer printing device, and an overcoat printing device, it is preferable that the printing device 11 applies ink to the outer surface of the barrel in the order of the primer printing device, the character image printing device, and the overcoat printing device.

[0049] As shown in Figure 1, the barreling system 1 preferably further comprises an external washing device 2 that washes the external surfaces of the barrels with external washing liquid, located upstream of the internal washing device 3 on the conveying path 6, and the printing device 11 applies the ink to the external surfaces of the barrels downstream of the external washing device 2 on the conveying path 6. This removes dirt and printed ink from the external surfaces of barrels returned from the market, making the surfaces easier to print on. The printing device 11 preferably has a portion that supplies ink to the external surfaces of the barrels located along the conveying device 5b between the external washing device 2 and the internal washing device 3.

[0050] As shown in FIG. 1, the barrel printing system 10 according to this embodiment preferably further includes a draining device 13 located downstream of the external washing device 2 on the conveying path 6 and upstream of the printing device 11 on the conveying path 6, for removing the external washing liquid adhering to the external surface of the barrel due to washing in the external washing device 2. This allows moisture to be removed from the surface to which the ink is to be applied, thereby preventing chipping or bleeding of the print. The draining device 13 is, for example, a blower or wiper, and is more preferably a blower. The air blown from the blower may be room temperature air or warm air.

[0051] FIG. 3 is a schematic diagram illustrating the lifting and rotating device. In FIG. 3, the barrels 100 (B1, B2, B3) and the lifting and rotating device 12 are simplified and cylindrical, and the ink dot group P is represented by diagonal hatching. In the barrel printing system 10 according to this embodiment, the printing device 11 is an inkjet printer with an inkjet head. The barrel printing system 10 further includes a lifting and rotating device 12 that lifts the barrel 100 conveyed by the conveying device 5 from the conveying surface of the conveying device 5 and rotates the barrel 100 about its central axis O. Preferably, the inkjet head 11a faces the side of the barrel 100 lifted by the lifting and rotating device 12. The lifting and rotating device 12 rotates the barrel 100 immediately after lifting it, and the inkjet head 11a prints on the side of the barrel 100. This allows printing to be achieved without requiring major layout changes to the existing barreling system 1, with only minor modifications to the details, such as incorporating the printing device 11 and the lifting and rotating device 12.

[0052] The lifting and rotating device 12 preferably has a gripping part that grips the barrel 100, a lifting part that moves the barrel 100 up and down, and a rotating part. The gripping part is a mechanism that detachably fixes a predetermined part of the barrel 100. The predetermined part of the barrel 100 is not particularly limited, and may be, for example, the upper skirt part 102 or the lower skirt part 103. The method of fixing the barrel 100 by the gripping part is not particularly limited, and may be, for example, engagement, clamping, or suction. The lifting part is a mechanism that moves the gripping part up and down. The rotating part is a mechanism that rotates the barrel 100 gripped by the gripping part around the central axis O of the barrel 100. The central axis O of the barrel 100 is an axis that extends in the vertical direction of the barrel 100, and may be, for example, the axis of a spear valve.

[0053] The inkjet head 11a is fixed so as to face a portion of the side surface of the barrel 100 that is lifted by the lifting and rotating device 12, which will be the printing area. Then, when the inkjet head 11a ejects ink toward the side surface of the barrel 100 while the lifting and rotating device 12 lifts and rotates the barrel 100, a group of ink dots P adheres to the side surface of the barrel 100, forming characters or images, or both.

[0054] The barrel printing system 10 according to this embodiment may include one inkjet head 11a or two or more inkjet heads 11a. When there is one inkjet head 11a, the inkjet head 11a is disposed on either the left or right side of the conveying device 5 in the conveying direction X. Printing is performed while the barrel 100 is rotated by the lifting and rotating device 12, so printing can be performed efficiently even with only one inkjet head 11a. This also saves space. When there are two or more inkjet heads 11a, two or more inkjet heads 11a may be arranged in parallel on either the left or right side of the conveying device 5 in the conveying direction X, or two inkjet heads 11a may be arranged facing each other on both the left and right sides of the conveying device 5 in the conveying direction X. By disposing two inkjet heads 11a facing each other on both the left and right sides of the conveying device 5 in the conveying direction X, printing can be performed simultaneously from both sides of the barrel 100, thereby reducing printing time.

[0055] In FIG. 3, when the printing device 11 is a character image printing device and a primer printing device, the inkjet head of the primer printing device and the inkjet head of the character image printing device are preferably arranged side by side around the side of the barrel 100 (B2) rotated by the lifting and rotating device 12 shown in FIG. 3. The inkjet head of the primer printing device is preferably arranged upstream of the inkjet head of the character image printing device in the rotation direction of the barrel 100. Since the primer ink and the character image ink are printed while the lifting and rotating device 12 rotates the barrel 100, printed materials can be formed efficiently. Furthermore, space can be saved. Printed materials having a primer layer and a character image ink layer can be formed efficiently without stopping the conveying device 5.

[0056] In FIG. 3, when the printing device 11 is a character image printing device and an overcoat printing device, the inkjet head of the character image printing device and the inkjet head of the overcoat printing device are preferably arranged side by side around the side of the barrel 100 (B2) rotated by the lifting and rotating device 12 shown in FIG. 3. The inkjet head of the overcoat printing device is preferably arranged downstream of the inkjet head of the character image printing device in the rotation direction of the barrel 100. Since the character image ink and the overcoat ink are printed while the lifting and rotating device 12 rotates the barrel 100, printed materials can be formed efficiently. Furthermore, space can be saved. Printed materials having a character image ink layer and an overcoat ink layer can be formed efficiently without stopping the conveying device 5.

[0057] In FIG. 3, when the printing device 11 is a character image printing device, a primer printing device, and an overcoat printing device, the inkjet heads of the primer printing device, the inkjet heads of the character image printing device, and the inkjet heads of the overcoat printing device are preferably arranged around the side of the barrel 100 (B2) rotated by the elevator and rotation device 12 shown in FIG. 3. The inkjet heads of the primer printing device, the inkjet heads of the character image printing device, and the inkjet heads of the overcoat printing device are preferably arranged in order from the upstream side in the rotation direction of the barrel 100. Printing of the primer ink, the character image ink, and the overcoat ink is performed while the elevator and rotation device 12 rotates the barrel 100, allowing for efficient printing. Furthermore, space savings are possible. Printed materials having a primer layer, a character image ink layer, and an overcoat ink layer can be efficiently formed without stopping the conveying device 5.

[0058] The inkjet head of the primer printing device, the inkjet head of the character image printing device, and the inkjet head of the overcoat printing device may each be one or more. By arranging multiple inkjet heads, the primer layer, the character image layer, and the overcoat layer can be printed without gaps or printed thickly.

[0059] Next, a description will be given of a barrel printing method according to this embodiment. The barrel printing method according to this embodiment is a barrel printing method for printing on the outer surfaces of barrels in a barrel filling system that transports returnable barrels along a predetermined transport path and fills the barrels with contents. The barrel filling method in the barrel filling system includes a steam sterilization step in which steam at 100°C or higher is introduced into the internal space of the barrel, and the barrel printing method includes an ink application step that is carried out before the steam sterilization step in which ink is applied to the outer surfaces of the barrels, and a main drying step that, after the steam sterilization step, uses the temperature rise of the barrels in the steam sterilization step to completely dry the ink that has been applied to the outer surfaces of the barrels in the ink application step.

[0060] The kegging method is a method in which returnable keg collected from the market such as a store is washed and sterilized using a kegging system 1 shown in FIG. 1, and then refilled with the contents.

[0061] In the barrel printing method according to this embodiment, the barrel filling method further includes a filling step of filling the contents into the barrel after the steam sterilization step. The filling step is a step of supplying the contents into the barrel using, for example, a filling device 4 shown in FIG.

[0062] The steam sterilization step is a step in which steam for sterilization is introduced into the barrel by, for example, an internal cleaning device 3 shown in FIG. 1. The steam is, for example, saturated steam or superheated steam. The temperature of the steam is 100°C or higher, preferably 115°C or higher, and more preferably 120°C or higher. There is no particular limitation on the upper limit of the steam temperature, but it is, for example, preferably 200°C or lower, and preferably 150°C or lower.

[0063] The barrel filling method preferably further includes an internal washing step, prior to the steam sterilization step, in which an internal washing liquid for washing is introduced into the barrel by an internal washing device 3. The internal washing liquid is a cleaning liquid.

[0064] The barrel printing process is carried out while the barrel filling process is in progress.

[0065] In the ink application process, ink is applied to the outer surface of the barrel by the printing device 11 to form a print design such as predetermined characters and / or images. The ink application process may be a process of printing only one layer, or a process of printing two or more layers. An example of a process of printing two or more layers is a process of applying multiple layers such as a primer ink layer, a character and image ink layer, and an overcoat ink layer.

[0066] The ink application process is carried out before the steam sterilization process, which allows the solvent in the ink to evaporate after the ink droplets have wetted and spread, resulting in highly distinctive printing.

[0067] In the barrel printing method according to this embodiment, the ink is preferably water-based ink. This ink can be more easily removed by alkaline cleaning compared to when oil-based ink is used. Furthermore, printing can be performed more safely. By using alkali-soluble water-based ink in the ink application process, when the barrels are collected after distribution to the market, the printed design can be removed by alkaline cleaning in the exterior washing process, ensuring the reusability of the barrels.

[0068] This drying process dries the ink that has been applied to the outer surface of the barrel in the ink application process to a degree that prevents discoloration or color transfer due to rubbing. This drying process utilizes the temperature rise of the barrel in the steam sterilization process to volatilize the solvent in the ink. The temperature of the outer surface of the barrel immediately after the steam sterilization process is, for example, about 100 to 150°C, and the solvent in the ink that has been applied to the outer surface of the barrel volatilizes in a short period of time.

[0069] In the barrel printing method according to this embodiment, the barrel filling method preferably further includes an external washing step in which the outer surface of the barrel is washed with an external washing liquid before the steam sterilization step, and the ink application step is preferably performed after the external washing step. By performing the ink application step after the external washing step, dirt and printed ink adhering to the outer surface of the barrel returned from the market can be removed, making the surface easier to print on. Furthermore, by performing the ink application step after the external washing step and before the steam sterilization step, the ink can be fixed in a wet, spread state. As a result, highly distinctive printing can be performed.

[0070] The external washing process is a process for removing dirt and printed ink adhering to the outer surface of the barrel, for example, using an external washing device 2 shown in Figure 1. The external washing process preferably includes an alkaline washing process in which the outer surface of the barrel is washed with an alkaline washing solution as the outer washing solution, and a finish washing process in which the outer surface of the barrel is washed with a finishing solution as the outer washing solution. The alkaline washing solution is an alkaline liquid. The temperature of the alkaline washing solution is not particularly limited, but is preferably 40 to 100°C, and more preferably 50 to 90°C. The finishing solution is a liquid used to wash away the alkaline washing solution remaining on the outer surface of the barrel after washing with the alkaline washing solution, and is, for example, hot water or water. The temperature of the finishing solution is not particularly limited, but is preferably 40 to 100°C, and more preferably 50 to 90°C.

[0071] In the barrel printing method according to this embodiment, the exterior washing step preferably includes a finishing washing step in which the exterior washing liquid is a finishing liquid at 40 to 100°C. The barrel printing method also preferably includes a pre-drying step, which is performed after the ink application step and before the steam sterilization step, in which the ink applied to the exterior surface of the barrel in the ink application step is pre-dried by increasing the temperature of the barrel in the finishing washing step. This allows the ink applied to the exterior surface of the barrel to dry at a more appropriate drying rate. As a result, the ink droplets are spread out, reducing the gaps between the ink droplets and preventing ink dripping.

[0072] The pre-drying process achieves the following effects. For example, the exterior surface of the barrel is washed with an alkaline cleaning solution at approximately 60°C in the external washing device 2, and then washed with a finishing solution at approximately 60°C. At this time, the temperature of the exterior surface of the barrel after the external washing process is higher than the ambient temperature but lower than the temperature at which the solvent in the ink dries instantly. By applying ink to the exterior surface of the barrel in this state, the ink droplets wet and spread while the solvent gently evaporates. As a result, ink dripping during printing can be prevented without creating gaps between the ink droplets. Then, by performing a steam sterilization process using steam at 100°C or higher in the internal washing device 3, most of the solvent evaporates in a short time during the main drying process, allowing the ink droplets to be fixed in a wet, spread state. As a result, the distinctiveness of the print can be ensured.

[0073] The barrel printing method according to this embodiment preferably further includes a draining step, which removes the external washing liquid adhering to the outer surface of the barrel after the external washing step and before the ink application step. This can prevent chipping or bleeding of the print. The draining step is a step in which the external washing liquid remaining on the outer surface of the barrel is removed, for example, by a draining device 13 shown in FIG. 1.

[0074] In the barrel printing method according to this embodiment, the ink deposition process is preferably performed while the temperature of the barrel's outer surface is maintained at 40 to 100°C. The temperature range of the barrel's outer surface during this ink deposition process is set to be higher than the ambient temperature but lower than the temperature at which the solvent in the ink dries instantly. This allows the ink deposited on the barrel's outer surface to dry at a more appropriate drying rate. As a result, the ink droplets are wetted and spread, reducing the gaps between the ink droplets and preventing ink dripping. A state in which the temperature of the barrel's outer surface is 40 to 100°C corresponds, for example, to a state in which the exterior washing process includes a finish washing process using hot water as a finishing liquid, and the temperature of the barrel is raised by this finish washing process. It is more preferable that the temperature of the barrel's outer surface during the ink deposition process be 50 to 90°C.

[0075] In the barrel printing method according to this embodiment, the time from the end of the ink application process to the start of the steam sterilization process is preferably shorter than the time from the end of the external washing process to the start of the ink application process. Even if external washing liquid remains near the ink-applied portion, the ink can be fixed by the main drying process before the ink bleeds due to dripping. This prevents the print from bleeding due to dripping. There are no particular limitations on the method for shortening the time from the end of the ink application process to the start of the steam sterilization process compared to the time from the end of the external washing process to the start of the ink application process. For example, the length of the transport path 6 between the printing device 11 and the internal washing device 3 can be shorter than the length of the transport path 6 between the external washing device 2 and the printing device 11.

[0076] As explained above, the barrel printing system and method according to this embodiment successfully improves identification by performing direct printing on the inner surface of the barrel before steam sterilization. Furthermore, direct printing can replace stretch labels. As a result, the amount of plastic used can be reduced, allowing customers to provide environmentally friendly products. Furthermore, by utilizing the current barreling system and method, a direct printing device can be realized that does not require a new drying system. [Example]

[0077] Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[0078] (Production of barrels for tests 1 and 2) The outer surface of a stainless steel barrel was heated to temperatures of 20°C, 30°C, 40°C, 50°C, 90°C, and 120°C, and then printed on the outer surface of the barrel using an inkjet printer (model: KM800, manufactured by Konica Minolta). The outer surface of the barrel was heated by leaving it in a thermostatic chamber with adjustable temperature. The temperature of the outer surface of the barrel was measured using a contact-type temperature sensor. The text "Kirin Lager Beer" (Kirin Lager is a registered trademark), "7L," and "Beer" were printed in red, and the image was a two-dimensional code printed in black.

[0079] (Test 1: Relationship between the temperature of the barrel's outer surface and ink drying) To confirm the relationship between the temperature of the outer surface of the barrel and the drying of the ink, the following evaluation was carried out. For each barrel temperature, a portion including the printed area was cut out from the barrel immediately after printing to prepare a test piece. A color fastness test was carried out on the printed portion of the test piece using a dyed material rubbing fastness tester (model: RT-200, company name: Nippon TMC Co., Ltd.) in accordance with JIS L 0849:2013 "Test method for color fastness to rubbing," and the condition of the printed area after rubbing was confirmed. ○: No color fading △: There is slight discoloration ×: Significant color fading

[0080] (Test 2: Relationship between the temperature of the barrel's outer surface and ink wetting and spreading) The following evaluation was carried out to confirm the relationship between the temperature of the barrel's outer surface and the wetting and spreading of the ink. The barrel was heated to each test temperature in a thermostatic chamber, and printing was performed. A predetermined area of ​​the printed area was magnified and observed using a microscope (model: Mx61, manufactured by SKYBASIC, magnification: 50 to 1000 times). The magnified image was visually observed to confirm the wetting and spreading state. ○: There are no gaps between ink droplets throughout the entire observation area, and the ink is sufficiently wet and spread. △: There are areas in the observation area where there are no gaps between the ink droplets and areas where there are gaps between the ink droplets, but the ink is wetting and spreading ×: Many gaps are observed between ink droplets throughout the observation area, and the ink does not spread widely.

[0081] Figures 4 and 5 show the evaluation results for "Test 1: Relationship between barrel outer surface temperature and ink drying." In Figures 4 and 5, the images in the "Immediately after printing" column are images of the printed area immediately after printing at each temperature, and the images in the "After rubbing" column are images of the printed area after the color fastness test against rubbing. As shown in Figures 4 and 5, the printed images immediately after printing were distinguishable at all temperatures. At 20°C and 30°C, color fading was observed upon rubbing immediately after printing, but at 40°C, color fading was slight and at a level that could be managed to prevent it from occurring during the manufacturing process. At 50°C, 90°C, and 120°C, no color fading was observed even immediately after printing.

[0082] Figures 6 and 7 show the evaluation results of "Test 2: Relationship between the temperature of the outer surface of the barrel and the wetting and spreading of the ink." In Figures 6 and 7, the images in the "Printed Image" column are photographs of the printed area after printing and drying at each temperature. "Enlarged Image 1" is an enlarged image of the "Kirin Lager (registered trademark)" text portion within the circled portion of the "Printed Image." "Enlarged Image 2" is an enlarged image of the 2D code portion within the circled portion of the "Printed Image." As shown in Figures 6 and 7, all of the printed images printed and dried at all temperatures were distinguishable. At 20°C, 30°C, 40°C, and 50°C, "Enlarged Image 1" and "Enlarged Image 2" confirmed that the ink had sufficiently spread to the point where the surface of the barrel was not visible. At 90°C, "Enlarged Image 1" and "Enlarged Image 2" confirmed that the ink had spread, although the surface of the barrel was slightly exposed. At 120°C, "Enlarged Image 1" and "Enlarged Image 2" confirmed that the ink had not spread much. Furthermore, when comparing the "printed images" for each temperature, the prints at 20 to 90°C were clearer and more distinguishable than those at 120°C.

[0083] From the above results, it was confirmed that from the viewpoint of drying property, it is more preferable that the temperature of the outer surface of the barrel during printing is 40 to 120°C, and from the viewpoint of distinguishability, it is preferable that the temperature of the outer surface of the barrel during printing is less than 120°C, and more preferably 20 to 90°C. It was also confirmed that a temperature range of 40°C or more and less than 120°C provides both drying property and high distinguishability. Note that although images processed to grayscale are shown in Figures 4 to 7, a more accurate representation can be achieved using color images before processing to grayscale. [Explanation of symbols]

[0084] 1. Barrelling System 2 External washing device 3 Internal washing device 4 Filling device 5(5a,5b,5c,5d) Conveying device 6. Transport Route 10. Barrel Printing System 11 Printing device 11a inkjet head 12 Lifting and rotating device 13 Draining device 100 barrels 101 Torso 101a Cap part 102 Upper skirt part 103 Lower Skirt 104 Handle

Claims

1. A barrel printing method for printing on an outer surface of a returnable barrel in a barrel filling system that transports the barrel along a predetermined transport path and fills the barrel with contents, comprising: The keg filling method in the keg filling system includes a steam sterilization step of introducing steam of 100°C or higher into the internal space of the keg, The barrel printing method includes: an ink application step, which is carried out before the steam sterilization step, of applying ink to the outer surface of the barrel; a main drying step in which, after the steam sterilization step, the ink adhered to the outer surface of the barrel in the ink adhering step is completely dried by the temperature increase of the barrel in the steam sterilization step; A barrel printing method comprising:

2. The barrel filling method further includes an external washing step of washing the outer surface of the barrel with an external washing liquid before the steam sterilization step, 2. The barrel printing method according to claim 1, wherein the ink application step is performed after the external washing step.

3. The barrel printing method according to claim 2, further comprising a draining step of removing the external washing liquid adhering to the outer surface of the barrel after the external washing step and before the ink application step.

4. The external washing step includes at least a finishing washing step of washing with a finishing liquid at 40 to 100°C as the external washing liquid, The barrel printing method includes: The barrel printing method according to claim 2, further comprising a pre-drying step, after the ink application step and before the steam sterilization step, in which the ink applied to the outer surface of the barrel in the ink application step is pre-dried by increasing the temperature of the barrel in the finishing cleaning step.

5. The barrel printing method according to claim 1, 2 or 4, characterized in that the ink adhesion process is carried out while the temperature of the outer surface of the barrel is maintained at 40 to 100°C.

6. 3. The barrel printing method according to claim 2, wherein the time from the end of the ink application process to the start of the steam sterilization process is shorter than the time from the end of the external washing process to the start of the ink application process.

7. 2. The barrel printing method according to claim 1, wherein the ink is a water-based ink.

8. 2. The barrel printing method according to claim 1, further comprising a filling step of filling the contents into the barrel after the steam sterilization step.

9. A barrel printing system for printing on the outer surface of a returnable barrel in a barrel filling system for filling contents into the barrel, The barreling system includes a conveying device that conveys the barrels along a predetermined conveying path, and an interior washing device that washes the interior surfaces of the barrels conveyed by the conveying device with an interior washing liquid and sterilizes them with steam at 100°C or higher, The barrel printing system is characterized in that it includes a printing device that applies ink to the outer surface of the barrel upstream of the internal cleaning device on the conveying path.

10. The barrel filling system further includes an external washing device located upstream of the internal washing device in the conveying path, the external washing device washing the external surface of the barrel with an external washing liquid, The barrel printing system according to claim 9 , wherein the printing device deposits the ink on the outer surface of the barrel downstream of the transport path from the external washing device.

11. The barrel printing system described in claim 10, characterized in that it further includes a draining device located downstream of the external washing device on the conveying path and upstream of the printing device on the conveying path, which removes the external washing liquid adhering to the outer surface of the barrel by cleaning in the external washing device.

12. The barrel printing system according to claim 10, wherein the external washing device has at least a finishing liquid supply device that supplies a finishing liquid at 40 to 100°C.

Images