JP7096083B2 - Continuous printing system - Google Patents

Description

The present invention relates to a system for continuously printing an image on a can using inkjet printing, a method for manufacturing a printing can using inkjet printing, and a printing can having inkjet printing on the surface.

In the seamless can manufacturing process, printing is performed on the can body after the can body and the bottom are integrally molded. When printing on the can body is performed by offset printing by plate printing, the can and the blanket on which the plate image is formed are moved while pressing the outer peripheral surface of the can body against the upper surface of the blanket, so that the can is held on the blanket. Transfer the printed ink to the can body. Therefore, the ink is printed in the circumferential direction of the cylindrical can body.

At the time of ink transfer, the start portion and the end portion of the circumferential printing of the can (also referred to as the front end portion and the rear end portion of the ink layer. For example, 14b1 in FIG. 3, that is, the surface of the can first comes into contact with each other. It is necessary to match the front end on the side and the rear end on 14b2 after printing, but if the circumferential length is insufficient, the base metal of the can will be exposed, so it is usually , The overlapping portion is formed by superimposing the printing start portion and the printing end portion. However, the formation of the overlapped portion causes the ink to become thicker, which causes a problem of wrinkles starting from a step during the necking process and a deterioration in aesthetics due to a partial increase in density due to the thickening of the ink. In order to solve these problems, a technique is disclosed in which the ink area ratio of at least one of the ink layers at the front end portion and the rear end portion is made smaller than that of a normal printing layer (see Patent Document 1).

JP-A-2010-58399

It is difficult to print a high-definition image on the surface of a can by a printing method using a printing plate as described in Patent Document 1. Therefore, the present inventors have studied a can printing method in which an inkjet image is formed on the orbiting transport means and the formed inkjet image is transferred to the surface of the can. It has been found that it is necessary to prevent ink from remaining on the transport means after transfer (so-called ink residue) so as not to interfere with the formation of the inkjet image.

On the other hand, as examined by the present inventors, even when the inkjet image on the transport means is transferred to the can by using the orbiting transport means, the inkjet image is still printed in the circumferential direction of the can body. Therefore, in order to prevent the base metal of the can from being exposed, it was found that there is no choice but to form an overlapping portion in which the front end portion and the rear end portion of the ink layer overlap.
However, when the formation of the overlap portion is applied to a printing method of transferring an inkjet image on the transport means to a can by using an orbiting transport means, the ink layer and the ink layer are overlapped in the overlap portion. Therefore, I came up with a new problem that ink residue is likely to occur on the transport means. The present invention solves a new problem that arises when applying a printing method for transferring an inkjet image on a transport means to a can by using such an orbiting transport means.

The present inventors have studied to solve the above problems, and have an image forming means for forming an inkjet image, a circular image conveying means for conveying the formed inkjet image to a transfer means, and an image conveying means. In an inkjet continuous printing system including a transfer means for transferring a printed inkjet image to a can and a can transport means for transporting a can as a printed matter to the transfer means, the ink in the overlapping portion of the inkjet image is included. He found that the problem of ink residue could be solved by reducing the amount, and completed the invention.

The present invention comprises an image forming means for forming an inkjet image and
An orbiting image transporting means for transporting the formed inkjet image to the transfer means,
A transfer means for transferring an inkjet image conveyed by the image transfer means to a can, and a transfer means.
An inkjet continuous printing system including a can transporting means for transporting a can as a printed matter to the transfer means.
The inkjet image formed on the image transporting means by the image forming means is located between the overlapping portion and the overlapping portion where the end portions of the inkjet image in the can circumferential direction overlap each other when transferred to the can. It has a main body portion, and at least one of the ink amount ratio and the ink area ratio of at least a part of the overlap portion is smaller than one of the ink amount ratio and the ink area ratio of the main body portion.
Inkjet continuous printing system, including.

As a specific form of the overlap portion, at least one of the ink amount ratio and the ink area ratio is gradually reduced from the main body portion side toward the end side, and at least one of the ink amount ratio and the ink area ratio is the main body portion. Examples thereof include a form having a flat mesh portion smaller than the ink amount ratio and the ink area ratio.
Further, examples of the circular image transporting means include a flexible belt-shaped transporting means, a cylinder-shaped transporting means, and the like, and it is preferable to have a peeling layer on the surface from the viewpoint of preventing ink residue.

The present invention also comprises, as another embodiment, an image forming step of forming an inkjet image on an orbiting image conveying means.
A transport step of transporting the formed inkjet image to the transfer means,
A transfer step of transferring the transferred inkjet image to a can transferred to the transfer means, and a transfer step.
It is a manufacturing method of printing cans including
In the inkjet image formed in the image forming step, an overlapping portion in which the end portions of the inkjet image in the can circumferential direction overlap each other when transferred to a can, and a main body portion located between the overlapping portions are provided. At least one of the ink amount ratio and the ink area ratio of at least a part of the overlap portion is smaller than one of the ink amount ratio and the ink area ratio of the main body portion.
Includes printing can manufacturing methods.

The present invention is still another form of a printing can having an inkjet image printing layer, wherein the inkjet image printing layer has an overlapping portion on which the inkjet images overlap, and the overlapping portion of the overlapping portion. Includes a printing can, the thickness of which is substantially the same as the thickness of the portion other than the overlap portion.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to solve the problem of ink residue that occurs when an inkjet image on the orbiting transport means is transferred to a can to form an overwrap portion. Since no ink residue is generated, the print quality is improved and high-definition image printing on the can can be maintained. Further, by forming the overlapping portion that suppresses the increase in the ink thickness, it is possible to suppress the problem of wrinkles starting from the step, which occurs during the necking process, and the ink becomes thicker. It is possible to suppress the deterioration of aesthetics due to the partial increase in concentration. Further, since no ink residue is generated, it is not necessary to install a cleaning means for cleaning the transport means, and the system can be miniaturized. Moreover, since periodical confirmation and cleaning are not required, productivity is improved.

It is a schematic diagram which shows an example of the structure of the printing system which concerns on embodiment of this invention. It is a schematic diagram at the time of transferring an inkjet image to a can. It is a schematic diagram which shows an example of an inkjet image. It is a schematic diagram which shows an example of an inkjet image. It is a schematic diagram which shows an example of an inkjet image. It is a schematic diagram which shows an example of an inkjet image. It is a schematic diagram which shows another example of the structure of the printing system which concerns on embodiment of this invention.

An embodiment of the present invention includes an image forming means for forming an inkjet image and an image forming means.
An orbiting image transporting means for transporting the formed inkjet image to the transfer means,
A transfer means for transferring an inkjet image conveyed by the image transfer means to a can, and a transfer means.
It is an inkjet continuous printing system including a can transporting means for transporting a can as a printed matter to the transfer means. An example of this embodiment is shown in FIG.

FIG. 1 is a schematic view showing an example of the configuration of the printing system 100 according to the present embodiment.
The printing system 100 includes a printing station 10 which is an image forming means, a transport belt 20 which is an image transporting means, a transfer station 30 which is a transfer means, a mandrel wheel 40 and a mandrel 42 which are can transporting means, and a cleaning station 50 which is a cleaning means. And an overcoat station 60 which is a covering means. The printing system 100 may have a configuration other than these.

The printing station 10 includes a printing unit 11, and an inkjet printer head included in the printing unit 11 forms an inkjet image 14 (not shown) on a blanket 23 included in the transport belt 20. Only one printing unit 11 may be provided in the printing station 10, or a plurality of printing units 11 may be provided in the printing station 10. By having a plurality of printing units 11, it is possible to support high-speed printing and also to support a printing method having a large number of passes, so that the quality of the printed image is improved and the high-definition inkjet image 14 can be obtained. It can be formed on the blanket 23.

The inkjet printer head included in the printing unit 11 typically has a plurality of nozzle heads 12 for ejecting inks of each color of white (W), black (K), yellow (Y), magenta (M), and cyan (C). Is included. The order of the colors is not particularly limited, and the ink colors are not limited to these. Therefore, colorless clear ink may be used.

The printing unit 11 may be provided with a nozzle bed for ejecting a primer layer (Pr), and in that case, the formed inkjet image 14 is covered with the primer layer by being located downstream of the inkjet printer head. be able to. By covering the inkjet image 14 with the primer layer, it is possible to suppress the ink residue that may occur when the inkjet image 14 is transferred to the can 41.

The printing unit 11 may be further provided with a UV irradiation unit 13 as a curing means. When the ink ejected by the inkjet printer head is UV curable ink, semi-curing by UV irradiation can suppress the ink residue that may occur when the inkjet image 14 is transferred to the can 41 at the transfer station.
Further, instead of the UV irradiation unit 13, a drying means may be provided as a curing means. The drying means can semi-cure the inkjet image 14 by blowing warm air onto the inkjet image.
The inkjet image 14 may be formed directly on the transport belt 20 without using the blanket 23. In this case, it is preferable to provide a release layer on the surface of the transport belt 20 for the purpose of smooth transfer.

The transfer belt 20 has an annular shape via the first roller 21 and the second roller 22, and by rotating in the direction of the arrow in the figure, the inkjet image printed on the blanket 23 of the transfer belt 20 is transferred to the transfer station 30. To transport to. The number of blankets 23 of the transport belt 20 can be appropriately determined according to the circumference of the annular transport belt and according to the operating speed of the printing system.

The transport belt 20 may have flexibility, but if the material has excessive flexibility, the tension of the belt becomes insufficient, and deviation may occur during printing or transfer. The material of the transport belt 20 is not particularly limited.
In addition to the first roller 21 and the second roller 22, one or more auxiliary rollers may be provided for the purpose of guiding the transport belt.

The blanket 23 on which the inkjet image 14 is formed is conveyed to the transfer station 30 along the outer circumference of the first roller 21. On the other hand, a plurality of cans 41 are conveyed to the transfer station 30 by the mandrel wheel 40. The can 41 starts rotating when the tip of the blanket 23 comes into contact with the conveyed can 41 or just before the can 41, and after the contact, the inkjet image 14 formed on the blanket 23 is the can 41. Is transferred in the circumferential direction of the can 41, and an inkjet image is formed on the surface of the can 41. The blanket 23 and the can 41 may be aligned as appropriate, and the alignment may be performed by a known method.
Further, when the tip of the blanket 23 comes into contact with the conveyed can 41, the rotation of the mandrel wheel 40 itself is stopped, and the can 41 of the mandrel 42 is rotated while the mandrel 40 is stopped to form on the blanket 23. The printed inkjet image 14 may be transferred to the can 41. The present embodiment can also be applied to such intermittent printing.

The inkjet image 14 on the blanket 23 has an overlap portion in which the end portions of the inkjet image in the can circumferential direction overlap each other when transferred to the can 41, and a main body portion located between the overlap portions. This will be described in detail with reference to FIGS. 2 to 6.

FIG. 2 is a schematic diagram showing a state in which an inkjet image is transferred to the can 41. In the transfer station 30, the can 41 is conveyed along the outer peripheral curved surface of the mandrel 42, but in FIG. 2, it is assumed that the can is conveyed on a flat surface.
The inkjet image 14 formed on the blanket 23 provided on the transport belt 20 is moved from the blanket 23 to the surface of the can 41 by the rotation of the can 41 in the arrow direction and the relative movement of the can 41 and the transport belt 20. Transferred. At this time, if the length of the inkjet image 14 in the length direction (length in the left-right direction in the figure) is smaller than the length in the outer peripheral direction of the can 41, the inkjet image is not transferred to a part of the can 41. Since the base metal of the can 41 is exposed, the overlap portion 14b (hereinafter also referred to as an OL portion) is provided by overlapping the ends of the inkjet image 14 to prevent the base metal of the can 41 from being exposed in this way. ..

On the other hand, the OL portion 14b of the inkjet image 14 is transferred not on the surface of the can 41 but on the image already transferred to the can 41. Therefore, since the ink layer and the ink layer are overlapped with each other, the inkjet image is not transferred well from the blanket 23, and a new problem is posed that ink residue is likely to occur on the blanket 23. This problem cannot be dealt with by surface treatment of the can 41 or the like. Therefore, in the present embodiment, at least one of the ink amount ratio and the ink area ratio of at least a part of the OL portion is made smaller than one of the ink amount ratio and the ink area ratio of the main body portion of the inkjet image. Here, the ink amount ratio means the total amount (volume) of ink on the unit area of the blanket (for example, 1 inch square), and the ink area ratio means the unit area of the blanket (for example, 1 inch square). It refers to the ink area on the corner), which will be described with reference to FIGS. 3 and 4.

FIG. 3 is a schematic top view of the inkjet image 14 formed on the blanket 23. The inkjet image 14 is conveyed together with the transport belt 20 in the direction of the arrow in the figure, and the OL portion 14b1 on the left side of the figure is the tip portion that first contacts the can 41, and the OL portion 14b2 on the right side of the figure is the rear end portion. be.
The inkjet image 14 has a main body portion 14a that does not overlap when transferred to the can 41, and an OL portion 14b that overlaps. Typically, the OL portion 14b is provided at both ends in the length direction of the front end portion 14b1 and the rear end portion 14b2 of the inkjet image 14, but only one of the front end portion and the rear end portion may be provided. The width of the OL portion (the length indicated by the double-headed arrow in the figure) is not particularly limited.

In the OL portion, at least one of the ink amount ratio and the ink area ratio of a part thereof is smaller than one of the ink amount ratio and the ink area ratio of the main body portion of the inkjet image. Although FIGS. 3 to 6 are shown as specific forms, the present invention is not limited to this form.
In FIG. 3, the OL portion 14b has a form in which the ink amount ratio gradually decreases from the main body portion 14a side toward the end portion of the OL portion 14b, which is a so-called gradation form. In the present embodiment, the amount of ink in the height (length in the vertical direction in the figure) direction of the inkjet image is uniform, but it may be different in the height direction. Further, although the amount of ink is reduced in both OL portions, the ink amount may be reduced in only one of the OL portions. The OL portion 14b in FIG. 3 has an ink amount ratio decreasing toward the end portion, which is smaller than the ink amount ratio of the main body portion 14a. Further, in FIG. 3, the ink amount ratio becomes smaller and the dot diameter of the ink becomes smaller, so that the ink area ratio also becomes smaller.

In FIG. 4, the OL unit 14b is a flat net unit. In the present embodiment, the ink amount of each halftone dot of the flat net unit is the same, but the gradation form as shown in FIG. It may be gradually reduced toward. The form shown in FIG. 3 and the form shown in FIG. 4 have a gradation or a flat mesh in the entire OL portion, but even if such a form is present only in a part thereof, the effect of improving the ink residue is improved. Therefore, it can be included in the present embodiment. In the OL portion 14b of FIG. 4, the ink amount at each halftone dot of the flat net unit is constant, but since the number of dots is small, the ink amount ratio of the flat net unit is higher than the ink amount ratio of the main body portion 14a. Is also small. Further, since the amount of ink is small and the number of dots is small, the ink area ratio is also small.
Further, in particular, in the form shown in FIG. 4, the halftone dots of the OL portion 14b-1 and the OL portion 14b-2 may be arranged at positions where the OL portion 14b-1 and the OL portion 14b-2 overlap each other. However, if the OL portions are arranged so as to be offset from each other, the inks do not overlap with each other, so that the effect of improving the ink residue can be enhanced. When the halftone dots are displaced from each other in each OL portion, the halftone dots may be partially overlapped, but a form in which the halftone dots do not completely overlap is preferable.

Further, even if the ink area ratio of the OL portion 14b is the same as the ink area ratio of the main body portion 14a, the ink amount ratio can be reduced by increasing the number of dots and reducing the ink amount of each dot, while the ink amount ratio can be reduced. Even if the ink amount ratio of the OL portion 14b is the same as the ink amount ratio of the main body portion 14a, the ink area ratio can be increased by reducing the number of dots and increasing the ink amount of each dot. Similar to the fourth embodiment, the effect of improving the ink residue can be obtained.

In addition to these, for example, only one of the tip portion 14b1 or the rear end portion 14b2 of the OL portion 14b may be used to gradually reduce the amount of ink from the main body portion 14a, and the tip portion 14b1 of the OL portion 14b is the tip from the main body portion 14a. While the amount of ink is gradually reduced toward, the tip portion 14b2 may gradually increase the amount of ink from the rear end toward the main body portion 14a. In any case, it suffices to have some kind of configuration for reducing the overlap of the OL portions.

In the embodiment shown in FIGS. 3 to 6, the ink amount ratio and the ink area ratio of the main body portion 14a show a constant form on the entire surface of the main body portion 14a. However, in the form in which there is a part where the ink does not get on a part of the main body portion 14a, the comparison between the ink amount ratio and the ink area ratio of the main body portion 14a and the ink amount ratio and the ink area ratio of the OL portion 14b is the main body. It is a comparison between the ink amount ratio and the ink area ratio of the portion of the portion 14a on which the ink is placed and the ink amount ratio and the ink area ratio of the OL portion 14b.

Although the OL portion has a rectangular shape in FIGS. 3 and 4, the OL portion is not limited to these shapes. For example, as shown in FIG. 5, the OL portion is inclined and extended with respect to the height direction of the can. However, as shown in FIG. 6, the OL portion may have a shape that is inclined and extended in a zigzag manner toward the height direction of the can. Further, the OL portion 14b may have a curved contour shape such that at least a part of the contour includes an arc.

A printing can having such an OL portion includes the following forms.
That is, it is a printing can having an inkjet image printing layer, and the inkjet image printing layer has an overlapping portion where inkjet images overlap, and the thickness of the overlapping portion is a portion other than the overlapping portion. Includes printing cans, which are approximately the same as the thickness of. Here, "substantially the same" means that the thickness of the overlap portion is 0.5 times or more the thickness of the portion other than the overlap portion, specifically, the thickness of the main body portion 14a referred to in FIGS. 3 to 6. It means that it is 1.5 times or less, the lower limit value may be 0.6 times or more, 0.7 times or more, 0.8 times or more, and the upper limit value is 1. It may be 4 times or less, 1.3 times or less, and 1.2 times or less.

Further, the printing can has an inkjet image printing layer, and the inkjet image printing layer has an overlapping portion on which the inkjet images overlap, and the printing color density of the overlapping portion is the overlapping portion. Includes printing cans, which are substantially the same as the printing density of the parts other than. Here, "substantially the same" means that the print density of the overlap portion is 0 with respect to the print density of the portion other than the overlap portion, specifically, the print density of the main body portion 14a shown in FIGS. 3 to 6. It means that it is 5 times or more and 1.5 times or less, and the lower limit value may be 0.6 times or more, 0.7 times or more, 0.8 times or more, and the upper limit value. May be 1.4 times or less, 1.3 times or less, and 1.2 times or less.

After the inkjet image 14 is transferred from the blanket 23 to the surface of the can 41 at the transfer station 30, the surface of the blanket 23 may be cleaned at the cleaning station 50. In the present embodiment, at least one of the ink amount ratio and the ink area ratio of the OL portion 14b of the inkjet image 14 is made smaller than one of the ink amount ratio and the ink area ratio of the main body portion 14a, so that the ink jet image 14 is placed on the blanket 23. Ink residue can be suppressed. On the other hand, since it is possible that all the ink is not transferred, a cleaning station 50 may be provided to clean the ink on the blanket 23.

The cleaning station 50 typically includes a cleaning agent supply unit 51 that discharges the cleaning agent onto the blanket 23, and a scraper 52 that wipes off the ink on the blanket 23. The blanket 23 whose surface has been washed by the washing station 50 is guided by the second roller 22 and conveyed to the printing station 10 again, on which the inkjet image 14 is formed.

The can 41 to which the inkjet image 14 is transferred is conveyed to the overcoat station 60 by the mandrel wheel 40. At the overcoat station 60, the inkjet image 14 transferred onto the surface of the can 41 is coated. A varnish is typically used for the coating, but other coatings may be used as long as they can protect the inkjet image and improve durability.

FIG. 7 is another example of the printing system of the present embodiment. The image printing system 200 is an example in which the transport cylinder 120 is used as the image transport means. The transport cylinder 120 is typically a metallic cylindrical member. As in the case of the transport belt 20, the blanket 123 is provided, and the inkjet image 114 (not shown) is formed on the blanket 123 at the printing station 110. The inkjet image 114 may be formed directly on the transport cylinder 120 instead of on the blanket 123. In this case, it is preferable to provide a release layer on the surface of the transport cylinder 120 for the purpose of smooth transfer.

The transport cylinder 120 may be provided with a curing means (not shown) inside. Also. A drying means may be provided instead of the UV irradiation unit 113 which is a curing means. The drying means makes it possible to evaporate the solvent of the inkjet image 114 to make it semi-cured. Further, when a thermosetting resin is used as the binder of the ink forming the inkjet image 114, it is semi-cured by heat, and the transfer to the can 141 can be easily performed.

As described above, in the printing systems 100 and 200 shown in FIGS. 1 and 7, an inkjet printing method is adopted for printing on the blanket, and an image for transfer to the can is directly formed on the blanket. In the conventional plate printing as shown in Patent Document 1, a plate is created including the overlap portion, and an image for transfer is formed on the blanket. Therefore, if the printed condition of the overlapped portion is poor or deteriorated, it must be remade from the plate. In the printing system shown in FIGS. 1 and 7, the state of the ink remaining in the overlapped portion is appropriately inspected, and each time, the portion where the ink amount ratio in the overlapped portion is reduced and / or the portion where the ink area ratio is reduced is reduced. Can be adjusted only by printing an image from the ink head to the blanket. Therefore, even if ink remains in the printed image of the overlap portion set at the beginning, it can be easily adjusted. Further, even if the printing state on the blanket changes after printing for a long time and ink remains, it is possible to quickly return to high-definition image printing and improve the yield of the printing can. Furthermore, it is possible to print high-definition images for a long time.

Although specific embodiments of the present invention have been described above, these are representative examples, and the present invention is not limited to these contents as long as the gist of the present invention is not exceeded, and those skilled in the art will carry out various modifications. Including the form to be used.

100, 200 Printing system 10, 110 Printing station 11, 111 Printing unit 12, 112 Nozzle head 13, 113 UV irradiation unit 14 Inkjet image 14a Main unit 14b OL unit 14b1 Tip of OL 14b2 Rear end 20 of OL Belt 21 1st roller 22 2nd roller 23, 123 Blanket 30, 130 Transfer station 40, 140 Mandrel wheel 41, 141 Can 42, 142 Mandrel 50, 150 Cleaning station 51, 151 Cleaning agent supply section 52, 152 Scraper 60, 160 Overcoat Station 120 Conveyance Cylinder

Claims (12)

An image forming means for forming an inkjet image and
An orbiting image transporting means for transporting the formed inkjet image to the transfer means,
A transfer means for transferring an inkjet image conveyed by the image transfer means to a can, and a transfer means.
An inkjet continuous printing system including a can transporting means for transporting a can as a printed matter to the transfer means.
The inkjet image formed on the image transporting means by the image forming means is located between the overlapping portion and the overlapping portion where the end portions of the inkjet image in the can circumferential direction overlap each other when transferred to the can. It has a main body portion, and at least one of the ink amount ratio and the ink area ratio of at least a part of the overlap portion is smaller than one of the ink amount ratio and the ink area ratio of the main body portion.
Inkjet continuous printing system. The inkjet continuous printing system according to claim 1, wherein at least one of the ink amount ratio and the ink area ratio of the overlap portion gradually decreases from the main body portion side to the end portion side. The inkjet continuous printing system according to claim 1 or 2, wherein the overlapping unit has a flat net unit. The overlapping portion is a flat net unit and is provided at both ends in the length direction of the inkjet image.
The halftone dots of the overlap portion at one end in the length direction of the inkjet image and the halftone dots of the overlap portion at the other end are arranged so as to be offset from each other. The inkjet continuous printing system according to claim 1 or 2. The inkjet continuous printing system according to claim 1 or 2, wherein the overlap portion is provided at one end in the length direction of the inkjet image. The inkjet continuous printing system according to any one of claims 1 to 5 , wherein the circular image transporting means is a flexible belt-shaped transporting means or a cylinder-shaped transporting means. The inkjet contact printing system according to any one of claims 1 to 6 , wherein the circular image transporting means has a peeling layer on the surface. An image forming step of forming an inkjet image on an orbiting image conveying means,
A transport step of transporting the formed inkjet image to the transfer means,
A transfer step of transferring the transferred inkjet image to a can transferred to the transfer means, and a transfer step.
It is a manufacturing method of printing cans including
In the inkjet image formed in the image forming step, an overlapping portion in which the end portions of the inkjet image in the can circumferential direction overlap each other when transferred to a can, and a main body portion located between the overlapping portions are provided. At least one of the ink amount ratio and the ink area ratio of at least a part of the overlapped portion is smaller than one of the ink amount ratio and the ink area ratio of the main body portion.
How to make a printing can. The overlapping portion is a flat net unit and is provided at both ends in the length direction of the inkjet image.
The halftone dots of the overlap portion at one end in the length direction of the inkjet image and the halftone dots of the overlap portion at the other end are arranged so as to be offset from each other. The method for manufacturing a printing can according to claim 8. The method for manufacturing a printing can according to claim 8, wherein the overlapping portion is provided at one end in the length direction of the inkjet image. A printing can having an inkjet image printing layer.
The inkjet image printing layer has an overlapping portion where inkjet images overlap, and the thickness of the overlapping portion is substantially the same as the thickness of the portion other than the overlapping portion. The printing can according to claim 11, wherein the printing color density of the overlapping portion is substantially the same as the printing density of the portion other than the overlapping portion.

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