JP7214988B2 - How cans are made - Google Patents

Description

The present invention relates to a method for manufacturing printed cans.

Beverage cans are necked at the ends to reduce the amount of raw metal used. Various necking methods have been proposed (for example, Patent Document 1, etc.).

JP 2008-132522 A

Normally, when printing on an empty can, it is generally difficult to apply offset printing to the necking portion after the necking process, so printing is performed before the necking process. Prior to necking, a varnish layer is formed on the surface of the empty can in order to reduce friction during processing and improve slipperiness.
However, if printing is performed before the necking process, there is a risk that the printed part will wrinkle or peel off at the necking process during the necking process. In addition, since printing after the varnish layer is formed tends to repel ink, printing of images in particular tends to be avoided.
The present invention solves such problems.

The present inventors have studied to solve the above problems, and completed the present invention by printing an image on the varnish layer of an empty can having a necked opening.

That is, the present invention
A method of manufacturing a can, comprising a printing step of printing an image on the varnish layer of an empty can having a varnish layer on the can surface and a necked opening.

In addition, the necking process requires a varnish containing a wax component, and since the varnish contains a large amount of the wax component, the ink is repelled on the varnish surface, making it difficult to print as it is. Therefore, it is preferable to include a surface modification step of modifying at least part of the surface of the varnish layer before the printing step, and to print an image on the surface-modified can surface.
Moreover, it is preferable that the printing process is a printing process by inkjet printing.

In another aspect of the present invention, there is provided an empty can having a necked opening, wherein a varnish layer containing a wax component and an inkjet image layer are laminated in this order on the surface of the empty can. It's an empty can. It is preferable that a surface modified layer obtained by modifying the surface of the varnish layer is included between the varnish layer and the inkjet image layer.

According to the present invention, by printing an image on the varnish layer of the empty can after the necking process, the problem of wrinkling of the printed part and peeling off of the printed part at the necking process, which is caused by printing before the necking process. can solve the problem.
Furthermore, since the present invention makes it possible to print an image on the varnish layer of an empty can after necking, the timing of image printing in the can manufacturing process is improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows one form of the surface treatment apparatus which performs a surface modification process. FIG. 2A is a schematic top view of a printed layer on the surface of an empty can according to one embodiment, and FIG. FIG. 2A is a schematic top view of a printed layer on the surface of an empty can according to one embodiment, and FIG. FIG. 4A is a schematic top view of a printed layer on the surface of an empty can according to one embodiment, and FIG. FIG. 2A is a schematic top view of a printed layer on the surface of an empty can according to one embodiment, and FIG. 1 is a schematic diagram showing an example of the configuration of a printing system that performs a printing process; FIG.

One embodiment of the present invention is a method for manufacturing a can, comprising a printing step of printing an image on the varnish layer of an empty can having a varnish layer on the can surface and a necked opening. .
In the can manufacturing process, a necking process is generally performed to neck the opening. In this embodiment, the necking process is not particularly limited, and a known method is applied. Prior to the necking process, a varnish layer is applied to the surface of the empty can in order to reduce friction during processing and improve slipperiness. In the printing process of this embodiment, an image is printed on the varnish layer on the surface of the empty can.

In this embodiment, it is preferable to include a surface modification step of modifying at least part of the surface of the varnish layer before the printing step. and the adhesion of the image printed on the varnish layer is improved.
Moreover, in this embodiment, processes other than the surface modification process and the printing process may be included as necessary. A filling and sealing process in which empty cans with necked openings or surface-modified empty cans after necking are filled with contents and sealed, and after filling and sealing, the filled cans are sterilized by retorting, pasting, high-pressure sterilization, etc. It may include a sterilization treatment step for processing, and empty cans and filled cans placed in temporary storage (i.e., temporarily placed or temporarily stored) by a palletizer etc. A removal step of removing from the storage location may be included. Furthermore, a placement step of temporarily placing printed empty cans and filled cans after the printing step may be included. Needless to say, steps other than the steps described above may be included.

<Surface modification step>
The surface modification step is a step of modifying the surface of the varnish layer of the empty can. The method of the surface modification step is not particularly limited as long as the adhesion between the surface of the varnish layer of the empty can and the ink for image printing can be improved. For example, a method of blowing a combustion flame containing a silicon compound onto the surface of the varnish layer, a method of plasma-treating the surface of the varnish layer, a method of corona-treating the surface of the varnish layer, and a varnish applied to the surface of the varnish layer to improve ink adhesion. Examples include a method using varnish and a method of covering the surface of the varnish layer with a receiving layer that allows ink to stay on the surface of the varnish layer.
Among these, it is preferable to modify the surface by blowing a combustion flame containing a silicon compound. By blowing a combustion flame containing a silicon compound, a silicon oxide film can be formed on the surface of the varnish layer. By forming the silicon oxide film on the surface of the varnish layer, the adhesion between the ink and the varnish layer can be improved in the subsequent image printing.

A known method disclosed in, for example, Japanese Patent No. 3626424 or Japanese Patent No. 4366220 can be used to spray a combustion flame containing a silicon compound.
The silicon compound is not particularly limited, and typically includes silane compounds such as alkylsilanes and alkoxysilanes, but is not limited to these. These silane compounds may have nitrogen, halogens such as chlorine, vinyl groups, amino groups, and the like.
From the viewpoint of forming a good silicon oxide film on the surface of the varnish layer, the upper limit of the boiling point of the silicon compound is usually 250° C. or lower, may be 200° C. or lower, may be 180° C. or lower, or may be 150° C. or lower. It's okay. The lower limit is not particularly limited, and is usually 20°C or higher, and may be 50°C or higher.

The temperature of the combustion flame is not particularly limited, and may be generally 500° C. or higher, 550° C. or higher, or 600° C. or higher. The upper limit is usually 1500° C. or lower, may be 1250° C. or lower, or may be 1000° C. or lower.

Although the time for which the combustion flame is sprayed is not particularly limited, in the present embodiment, since the combustion flame is sprayed onto the varnish layer, it is preferable to perform the surface modification by spraying for a short period of time. It is preferred that the varnish layer on which the image is to be printed is sprayed with the combustion flame several times. In the present embodiment, the time for which the combustion flame is sprayed is preferably within 10 seconds, may be within 5 seconds, may be within 3 seconds, may be within 2 seconds, and may be within 2 seconds. It may be within 1 second. Although the lower limit is not particularly limited as long as the surface modification is performed, it is usually 0.001 seconds or more.

Fuel gas is generally used to provide a combustion flame. Combustible gases such as propane gas and natural gas are typically used as the fuel gas. Hydrogen, oxygen, air, or the like may be appropriately mixed with these combustible gases.

The amount of the silicon compound contained in the fuel gas is not particularly limited, but it is usually 1.0×10 ⁻¹⁰ mol % or more, and may be 1.0×10 ⁻⁹ mol % or more, relative to the total amount of the fuel gas. , 1.0×10 ⁻⁸ mol % or more. The upper limit is usually 10 mol % or less, may be 5 mol % or less, or may be 1 mol % or less.

FIG. 1 shows an example of a surface treatment apparatus for spraying combustion flames used for surface modification.
The surface treatment apparatus 10 includes an apparatus main body 6 having gas transfer sections 61a and 61b and an injection port 62, and a silicon supply section having a nozzle 21 for supplying a silicon compound to the apparatus main body 6 and a tank 22 for storing the silicon compound. 2, and a gas supply unit (not shown) that supplies gas to the gas transfer units 61a and 61b of the apparatus main body 6. As shown in FIG.

Combustion gas such as natural gas is supplied from the gas supply unit to the gas transfer unit 61a, and air is supplied as carrier gas from the gas supply unit to the gas transfer unit 61b. The gas transferred by the transfer parts 61 a and 61 b is mixed with the silicon compound supplied from the silicon supply part 2 and injected from the injection port 62 . Here, the mixed gas is ignited by separately provided ignition means, becomes combustion flame 5 , and is jetted onto the surface of the empty can 1 . The combustion flame 5 with the injected silicon compound forms a silicon oxide film on the surface of the empty can 1 .
Although the distance between the injection port 62 of the surface treatment apparatus 10 and the surface of the empty can 1 is not particularly limited, it is usually 1 cm or more, may be 3 cm or more, or may be 5 cm or more. Moreover, it is usually 30 cm or less, may be 20 cm or less, or may be 15 cm or less.

In the surface modification step, the varnish layer on the surface of the empty can is modified. Empty cans are not particularly limited, and typically include empty cans for filling foods and beverages, but are not particularly limited thereto.

A method for making empty cans is not particularly limited, and a known method can be applied. For example, methods for manufacturing two-piece cans include drawing, redrawing, and ironing. Methods for manufacturing three-piece cans include a tin plate cutting process, a roll forming process, a can body welding process, and a can body stretch forming process. In addition, there are paneling molding for deformed can bodies such as elliptical, square, and embossed can bodies, flange molding for seaming can lids, and necking molding. As already explained, the molded empty can is necked at the opening.

The surface of the molded empty can, particularly the surface of the can body, may be at least partly printed apart from the image printing described above. Although the printing method is not particularly limited, offset printing is a common printing method for cans. The printing process may be carried out on the formed empty can, or may be carried out at a plate-like stage before forming. A known method can be applied to offset printing on seamless cans, for example, a method of transferring ink to a blanket and continuously offset printing on the surface of seamless cans can be applied.

In this embodiment, an image is printed on the varnish layer after the necking process, but the area where the image is printed may not be printed at all. That is, the surface of the molded empty can may be partially printed, may have a non-printed portion, or may not be printed at all. Similarly, in order to make the printed image stand out, at least part of the surface of the empty can may be solidly printed, for example, solidly painted on a white background. However, the solid printing method is not limited to offset printing, and a white coater may be used. Also, the solid color is not particularly limited. Further, the solid coating printing process may be performed at any time until the image is printed on the varnish layer of the empty can.

After the image is printed on the varnish layer of the empty can, which has been preprinted as necessary before the image printing, the contents such as food and beverage are filled and sealed, and the contents are filled and sealed. filled cans. In many cases, the surface of the filled can after filling and sealing is further coated with a varnish containing wax.

<Printing process>
The printing process is a process of printing an image on the varnish layer of the empty can whose opening is necked. Preferably the image is an inkjet image. The image printing method is not particularly limited, and a known method is applied. For example, a method of directly printing ink onto an empty can by inkjet printing may be used, or a method of once forming an image on a transfer medium and then transferring the image to an empty can may be used. A known method may be applied to the method of directly printing the ink onto the empty can by inkjet printing. Inkjet printing enables pattern printing, photographic printing, image printing, etc., and dramatically improves the design of the surface of empty cans. In addition, in the present embodiment, by performing surface modification, in addition to improving adhesion to image printing, a silicon oxide film is formed by blowing a combustion flame containing a silicon compound to the varnish layer as the surface modification. Since the ink spreads well on the top, it also has the effect of preventing the base of the empty can from being seen through.
As printing other than inkjet printing, screen printing and hot stamping can also achieve similar effects.

Another embodiment of the present invention is a can manufactured by the manufacturing method described above, and has the following configuration. That is, it is an empty can that has undergone a necking process and has a varnish layer containing a wax component and an inkjet image layer laminated in this order on the surface of the empty can. Further, it is preferable that a surface modified layer obtained by modifying the surface of the varnish layer is included between the varnish layer and the inkjet image layer.
Alternatively, it may be an empty can that has undergone a necking process and has a solid printed layer, a varnish layer, a silicon oxide coating, and an inkjet image printed layer formed in this order on the surface of the empty can. These configurations will be described with reference to FIGS. 2 to 5. FIG.

FIG. 2 is a schematic top view (a) showing a printed layer printed on the surface of an empty can, which is developed on a plane, and a schematic cross-sectional view (b) taken along the line AA'.
As shown in FIG. 2A, the spread printing layer 100 has a first printing portion 101 and a second printing portion 102, and the first printing portion 101 has an image printed by plate printing. An inkjet image is printed on the second printing unit 102 by inkjet printing.
In this embodiment, a portion other than the second printed portion 102, that is, the first printed portion 101 is printed with a design image, and then the remaining second printed portion 102 is inkjet-printed to obtain a printed layer on the surface of the empty can. to form The sectional view differs between the first printing unit 101 and the second printing unit 102 as shown in FIG. 2B. The first printed part 101 is formed by laminating an image printed layer 104 and a varnish layer 105 in this order on the surface 103 of the empty can. On the other hand, the second printed portion 102 is formed by laminating a varnish layer 105, a silicon oxide film 106, and an inkjet image printed layer 107 on the surface 103 of the empty can. With such a form, it becomes possible to print a high-definition ink-jet image printing layer only on a necessary part.

As another form, the form of FIG. 3 is illustrated. Similarly, FIG. 3 is a schematic top view (a) showing the printed layer printed on the surface of the empty can, which is developed on a plane, and a schematic cross-sectional view (b) of the BB′ section. .
As shown in FIG. 3A, the spread printing layer 200 has a first printing portion 201 and a second printing portion 202. The first printing portion 201 has an image printed by plate printing. An inkjet image is printed on the second printing unit 202 by inkjet printing.
In this embodiment, the design image 204 is printed on the entire surface of the can, and varnish is applied. A printed layer is then formed by inkjet image printing. As shown in FIG. 3B for its cross-sectional view, the first printed portion 201 is formed by laminating an image printed layer 204 and a varnish layer 205 on a surface 203 of an empty can in this order. On the other hand, the second printing portion 202 is formed by laminating a silicon oxide film 206 , a solid printing layer 208 and an inkjet image printing layer 207 on an image printing layer 204 and a varnish layer 205 in this order. With such a form, it is also possible to print a high-definition inkjet image-printing layer only on a necessary portion.

FIG. 4 is a schematic top view (a) showing a printed layer printed on the surface of another form of empty can, which is developed on a plane, and a schematic cross-sectional view (b) of the CC′ section. is.
As shown in FIG. 4A, the entire surface of the development print layer 300 is printed with an inkjet image by inkjet printing. As shown in FIG. 4(b), the sectional view is such that a solid printed layer 304, a varnish layer 305, a silicon oxide film 306, and an ink jet image printed layer 307 are laminated in this order on the surface 303 of the empty can. The solid print layer 304 may be a white coating layer or other single color solid image. Due to the presence of the silicon oxide film 306, the inkjet image printing layer 307 has sufficient adhesion even on the varnish 305 with insufficient ink adhesion.

Moreover, the form of FIG. 5 is illustrated as another form. FIG. 5 is a schematic top view (a) showing a printed layer printed on the surface of another form of empty can, which is developed on a plane, and a schematic cross-sectional view (b) taken along line DD′. is.
As shown in FIG. 5A, the entire surface of the development print layer 400 is printed with an inkjet image by inkjet printing. A varnish layer 405 is laminated on the surface 403 of the empty can as shown in FIG. 5(b). That is, a silicon oxide film 406 is formed on the surface of an empty can, which is only coated with varnish, and a solid print layer 404 and an inkjet image print layer 407 are laminated thereon in this order.

<Filling and sealing process>
This embodiment may have a filling and sealing step of filling an empty can having an image printed on the varnish layer with contents. The filling and sealing step is a step of filling and sealing an empty can having a necked opening. The filling and sealing step is not particularly limited as long as the empty can can be filled with the contents and sealed, and can be appropriately carried out depending on the type of the contents and the type of the empty can.

An example of a printing system that performs a printing process for offset printing an inkjet image on the surface of an empty can will be described below with reference to FIG.
FIG. 6 is a schematic diagram showing an example of the configuration of the printing system I-100.
The printing system I-100 includes a printing station I-10 as image forming means, a transport belt I-20 as image transport means, a transfer station I-30 as transfer means, and a mandrel wheel I-40 as can transport means. It comprises a mandrel I-42, a washing station I-50 as washing means, and an overcoat station I-60 as coating means. The printing system I-100 may have configurations other than these.

The printing station I-10 comprises a printing unit I-11 which in turn prints an inkjet image I-14 (not shown) onto a blanket I-23 which is carried by a transport belt I-20 by means of an inkjet printer head provided by the printing unit I-11. is formed. There may be only one printing unit I-11 in the printing station I-10, or there may be a plurality of printing units. By having multiple printing units I-11, it is possible to respond to high-speed printing, and since it is also possible to respond to printing methods with a large number of passes, the quality of printed images is improved and high-definition inkjet images can be produced. I-14 can be formed on blanket I-23.

The inkjet printer head provided in the printing unit I-11 typically has a plurality of nozzles that eject inks of white (W), black (K), yellow (Y), magenta (M), and cyan (C). Head I-12 is included. The order of colors is not particularly limited, and the colors of ink are not limited to these. Therefore, clear ink may be used.

The printing unit I-11 may be provided with a nozzle bed for ejecting a primer layer (Pr), in which case it is positioned downstream of the inkjet printer head to apply a primer to the formed inkjet image I-14. It can be covered by layers.
The printing unit I-11 may further include a UV irradiation section I-13 as curing means. If the ink ejected by the inkjet printer head is UV curable ink, it is semi-cured by UV irradiation to suppress ink residue that may occur when the inkjet image I-14 is transferred to the can I-41 at the transfer station. can.
Also, instead of the UV irradiation section I-13, a drying means may be provided as a curing means. The drying means can semi-harden the inkjet image I-14 by a method such as blowing hot air onto the inkjet image.

The conveying belt I-20 is looped through a first roller I-21 and a second roller I-22. , to transfer station I-30. The number of blankets I-23 of the conveying belt I-20 can be appropriately determined according to the circumferential length of the annular conveying belt and the operating speed of the printing system.

The transport belt I-20 may be flexible, but if the material is excessively flexible, the tension of the belt may be insufficient, resulting in misalignment during printing or transfer. The material of the transport belt I-20 is not particularly limited.
In addition to the first roller I-21 and the second roller I-22, one or more auxiliary rollers may be provided for the purpose of guiding the transport belt.

Blanket I-23 with inkjet image I-14 formed thereon is transported along the circumference of first roller I-21 to transfer station I-30. Meanwhile, a plurality of cans I-41 are conveyed to transfer station I-30 by mandrel wheel I-40. When the tip of the blanket I-23 comes into contact with the transported can I-41, or just before it comes into contact with the can I-41, the can I-41 starts to rotate, and after contact, the blanket I-23 The inkjet image I-14 formed on the can is transferred in the circumferential direction of the can I-41 to form an inkjet image on the surface of the can I-41. The positioning of the blanket I-23 and the can I-41 may be performed as appropriate, and the positioning may be performed by a known method.
In addition, when the tip of the blanket I-23 contacts the transported can I-41, the rotation of the mandrel wheel I-40 itself is stopped, and the mandrel wheel I-42 is rotated while the mandrel wheel I-40 is stopped. The can I-41 may be rotated and the inkjet image I-14 formed on the blanket I-23 may be transferred to the can I-41. This embodiment can also be applied to such intermittent printing.

After inkjet image I-14 is transferred from blanket I-23 to the surface of can I-41 at transfer station I-30, blanket I-23 may be washed on its surface at washing station I-50. In this embodiment, the ink jet image I-14 can suppress ink residue on the blanket I-23 due to the presence of the connecting member. On the other hand, since it is possible that not all the ink is transferred, a washing station I-50 may be provided to wash the ink on the blanket I-23.

The cleaning station I-50 typically includes a cleaning agent supply I-51 for dispensing cleaning agent onto the blanket I-23 and a scraper I-52 for wiping ink off the blanket I-23. Blanket I-23, whose surface has been cleaned at cleaning station I-50, is guided by second roller I-22 and conveyed again to printing station I-10, where inkjet image I-14 is formed thereon.

Cans I-41 with ink jet image I-14 transferred thereto are transported by mandrel wheels I-40 to overcoat station I-60. At overcoat station I-60, the ink jet image I-14 transferred onto the can I-41 surface is coated. A varnish is typically used for the coating, but other materials may be used as long as they protect the ink jet image and improve its durability.

A surface modification means for modifying the surface of the can may be installed in the printing system I-100. For example, the surface modification means may be provided upstream of the transfer station of the can transport means.
Further, it goes without saying that the printing system I-100 shown in FIG. 6 may be used for pre-printing of empty cans.

10 Surface treatment device 1 Empty can 2 Silicon supply part 21 Nozzle 22 Container 3 Natural gas 4 Air 5 Combustion flame 6 Apparatus body 61a Gas transfer part 61b Gas transfer part 62 Injection ports 100, 200 Expanded printing layers 101, 201 First printing Parts 102, 202 Second printing parts 103, 203 Metal can surfaces 104, 204 Image printing layers 105, 205 Varnish layers 106, 206 Silicon oxide films 107, 207 Ink jet printing layers 300, 400 Development printing layers 303, 403 Metal can surfaces 304, 404, 208 solid print layers 305, 405 varnish layers 306, 406 silicon oxide coatings 307, 407 inkjet print layer I-100 print system I-10 print station
I-11 Printing unit I-12 Nozzle head I-13 UV irradiation part I-20 Conveyor belt I-21 First roller I-22 Second roller I-23 Blanket I-30 Transfer station I-40 Mandrel wheel I-41 Empty can I-42 Mandrel I-50 Washing station I-51 Cleaning agent supply section I-52 Scraper I-60 Overcoat station

Claims (4)

a surface modification step of modifying at least part of the surface of the varnish layer of an empty can having a varnish layer on the can surface and a necked opening;
a printing step of printing an image on the surface-modified surface of the varnish layer ;
The surface modification step comprises blowing a combustion flame containing a silicon compound onto at least a portion of the varnish layer surface, plasma-treating at least a portion of the varnish layer surface, and treating at least a portion of the varnish layer surface with corona. A method of manufacturing a can, comprising the step of treating or coating at least part of the surface of said varnish layer with an ink-receiving layer . The method for manufacturing a can according to claim 1 , wherein the printing step is a printing step by inkjet printing. 3. The method of manufacturing a tube according to claim 1, wherein the printing of the image in the printing step is applied at least to the necking processed portion. An empty can having a necked opening, comprising a varnish layer containing a wax component on the surface of the empty can , a surface-modified layer obtained by modifying at least a part of the surface of the varnish layer, and an inkjet. and an image layer are laminated in this order, the varnish layer is laminated on the surface of the empty can, the surface modification layer is a silicon oxide film or an ink receiving layer, and the inkjet image layer is at least necked. Empty cans formed into parts.

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