(19)
(11)EP 3 281 794 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
17.06.2020 Bulletin 2020/25

(21)Application number: 16776390.3

(22)Date of filing:  18.03.2016
(51)International Patent Classification (IPC): 
B41J 3/407(2006.01)
B05C 5/00(2006.01)
B41J 3/413(2006.01)
B41J 2/01(2006.01)
B41J 2/165(2006.01)
B65D 25/34(2006.01)
(86)International application number:
PCT/JP2016/058729
(87)International publication number:
WO 2016/163221 (13.10.2016 Gazette  2016/41)

(54)

PRINTING APPARATUS AND CAN BODY

DRUCKVORRICHTUNG UND DOSENKÖRPER

APPAREIL D'IMPRESSION ET CORPS DE BOÎTE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 10.04.2015 JP 2015081095

(43)Date of publication of application:
14.02.2018 Bulletin 2018/07

(73)Proprietor: Showa Aluminum Can Corporation
Tokyo 141-0031 (JP)

(72)Inventors:
  • OJIMA, Shinichi
    Tokyo 141-0031 (JP)
  • KASHIWAZAKI, Tetsuo
    Tokyo 141-0031 (JP)
  • IKEDA, Kazunori
    Tokyo 141-0031 (JP)
  • SUWA, Asumi
    Tokyo 141-0031 (JP)

(74)Representative: Strehl Schübel-Hopf & Partner 
Maximilianstrasse 54
80538 München
80538 München (DE)


(56)References cited: : 
WO-A1-2014/155781
JP-A- 2004 167 852
JP-A- 2006 272 571
JP-A- 2015 039 676
JP-B2- 6 259 612
US-A1- 2006 214 979
US-A1- 2010 031 834
US-A1- 2013 176 358
US-A1- 2014 028 771
JP-A- H06 156 503
JP-A- 2006 143 270
JP-A- 2012 101 516
JP-B2- 3 233 706
US-A1- 2006 055 715
US-A1- 2008 007 585
US-A1- 2012 139 980
US-A1- 2013 176 358
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Technical Field



    [0001] The present invention relates to a printing method to prepare a can body.

    Background Art



    [0002] In Patent Document 1, there is disclosed a printer including: a mandrel wheel; multiple automatically-rotatable mandrels provided in the mandrel wheel; and an inkjet printing station for forming a print image onto an outer surface of a cylindrical container installed in the mandrel.

    [0003] JP 6259612B2 I discloses further relevant background art.

    Citation List


    Patent Literature



    [0004] Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2014-50786

    Summary of Invention


    Technical Problem



    [0005] When printing by use of an ink jet head is performed onto a can body, if there is any unused ink ejection port or an ink ejection port not used frequently, ink clogging is likely to occur in the ink ejection port. Occurrence of the ink clogging can be suppressed by, for example, ejecting ink from the ink ejection port onto a can body; however, if the ink is ejected onto the can body, degradation in the quality of image to be formed is likely to be caused.

    [0006] An object of the present invention is, in ejecting ink from unused ink ejection ports or ink ejection ports not used frequently onto a can body to suppress ink clogging, to suppress the ink clogging while suppressing degradation in the quality of an image to be formed on the can body.

    Solution to Problem



    [0007] The present invention is directed to a printing method to prepare a can body and is defined in the appended claim.

    [0008] A printing apparatus used in the present invention is applied includes: an ink jet head that includes multiple ink ejection ports and ejects ink to an outer circumferential surface of a can body to perform image formation on the outer circumferential surface; and a head control unit that controls the ink jet head to form an image on the outer circumferential surface and ejects ink from at least one of an unused ink ejection port that is not used in forming the image and a low-frequency ink ejection port with a frequency of ink ejection lower than a predetermined frequency of ink ejection, the head control unit further causing, in ejecting the ink from at least one of the unused ink ejection port and the low-frequency ink ejection port, the ink to attach to a strip-shaped region of the outer circumferential surface that extends along an axial direction of the can body.

    [0009] Here, the multiple ink jet heads are provided and the respective ink jet heads eject inks of different colors from one another, and the head control unit controls the respective ink jet heads to produce a same color in respective pixels composing an image formed by attaching the ink to the strip-shaped region. In this case, it is possible to make the image formed in the strip-shaped region less conspicuous, as compared to a case in which colors of the respective pixels composing the image formed by attaching the ink to the strip-shaped region are different.

    [0010] Moreover, the head control unit attaches the ink to the strip-shaped region to form a character image that indicates a character within the strip-shaped region. In this case, it becomes possible to include character information in the image formed by attaching the ink to the strip-shaped region.

    [0011] The can body to which the method of the present invention is applied includes: a can main body that is formed cylindrically and includes an outer circumferential surface; and an image formed on the outer circumferential surface of the can main body by an ink jet head, wherein the image formed on the outer circumferential surface of the can main body includes a strip-shaped image that extends along an axial direction of the can main body and is formed in a strip shape.

    [0012] Here, the strip-shaped image is formed from one end portion to the other end portion in the axial direction of the can main body and in an entire region from the one end portion to the other end portion. In this case, it becomes possible to eject ink from more unused ink ejection ports or low-frequency ink ejection ports, as compared to a case in which the strip-shaped image is not formed in the entire region from the one end portion to the other end portion and the strip-shaped image includes blanks.

    [0013] Moreover, the multiple strip-shaped images are formed in rows and provided in positions shifted from one another in a circumferential direction and the axial direction of the can main body, and the multiple strip-shaped images are formed to generate an overlap between two strip-shaped images when the two strip-shaped images of the multiple strip-shaped images, which are adjacent to each other in the axial direction, are projected in the circumferential direction of the can main body. In this case, it becomes possible to eject ink from more unused ink ejection ports or low-frequency ink ejection ports, as compared to a case in which the overlap is not generated between the strip-shaped images.

    [0014] Moreover, the strip-shaped image is composed of an image including character images, each of which is an image indicating a character, arranged in line in the axial direction. In this case, it becomes possible to allow the strip-shaped image to have meaning.

    [0015] Moreover, the character images arranged in line in the axial direction are provided in multiple rows, and each of the character images is arranged to allow, between character images that are positioned in a row and are adjacent to each other in the axial direction, a character image in another row to be positioned. In this case, it becomes possible to eject ink from more unused ink ejection ports or low-frequency ink ejection ports, as compared to a case in which, between character images that are positioned in a row and are adjacent to each other, a character image in another row is not positioned.

    Advantageous Effects of Invention



    [0016] According to the present invention, in ejecting ink from unused ink ejection ports or ink ejection ports not used frequently onto a can body to suppress ink clogging, it is possible to suppress the ink clogging while suppressing degradation in the quality of an image to be formed on the can body.

    Brief Description of Drawings



    [0017] 

    FIGS. 1A and 1B are diagrams showing a can body of an exemplary embodiment;

    FIG. 2 is a diagram showing a can body subjected to printing by use of plate printing;

    FIGS. 3A and 3B are diagrams showing another configuration example of the can body;

    FIG. 4 is a diagram showing another arrangement example of strip-shaped images;

    FIGS. 5A to 5E are diagrams illustrating details of the strip-shaped image;

    FIG. 6 is a diagram in which a part of the strip-shaped image shown in FIG. 5C is enlarged; Fig. 6 and Fig. 5C show a strip-shaped image prepared according to the printing method of the present invention;

    FIG. 7 is a diagram illustrating each pixel constituting the strip-shaped image; and

    FIGS. 8A and 8B are diagram showing an example of a printing apparatus that performs above-described printing process.


    Description of Embodiments



    [0018] FIGS. 1A and 1B are diagrams showing a can body 100 of the exemplary embodiment. Note that FIG. 1A is a diagram viewing the can body 100 from diagonally above, and FIG. 1B is a development diagram of a can main body 110 (a barrel portion of the can body 100).

    [0019] As shown in FIG. 1A, the can body 100 is provided with the can main body 110 in a cylindrical shape.

    [0020] The can main body 110 has an outer circumferential surface 111. Further, the can body 100 is provided with a lid member 120 that closes an opening positioned at one end portion of the can main body 110. Further, a bottom portion (not shown) is provided to an opposite side of the lid member 120.

    [0021] As shown in FIGS. 1A and 1B, on the outer circumferential surface 111 of the can main body 110, a main image MG, which is a main image, and a strip-shaped image OG, which is a sub-image, are formed.

    [0022] Here, the main image MG is, for example, an image serving as a "face" of a product and an image representing imagery or the like of a product. The main image MG is formed on a main image formation region 151 extending along the circumferential direction of the can main body 110.

    [0023] The strip-shaped image OG is an image extending along the axial direction of the can main body 110 and formed in a strip shape.

    [0024] The strip-shaped image OG is, as shown in FIG. 1A, formed from one end portion to the other end portion in the axial direction of the can main body 110 over an entire region extending from the one end portion to the other end portion. Here, the strip-shaped image OG is composed of, for example, patterned designs, characters, symbols or others. Moreover, the strip-shaped image OG is formed in a strip-shaped image formation region 152 formed in a rectangular shape.

    [0025]  Further, in the exemplary embodiment, each of the main image MG and the strip-shaped image OG is formed by the so-called ink jet method. In the exemplary embodiment, the main image MG and the strip-shaped image OG are formed by ejecting ink from ink jet heads (ink jet print heads) toward the outer circumferential surface 111 of the can main body 110.

    [0026] To describe further and specifically, in the exemplary embodiment, multiple inkjet heads are prepared and different colors of ink are ejected from the respective ink jet heads toward the outer circumferential surface 111 of the can body 100. An ink ejection surface of the inkjet head is provided with multiple ink ejection ports, and ink is ejected from the ink ejection port corresponding to the image to be formed.

    [0027] Each inkjet head is provided with multiple rooms (hereinafter, referred to as "ink chambers") provided to ejection drive units, such as piezoelectric elements, and the ink ejection port is provided to each ink chamber.

    [0028] The ink supplied to each of the ink jet heads is supplied to the ink chamber via a manifold.

    [0029] By the way, to form the image on the can body 100, the ink is ejected from the ink ejection port corresponding to the image to be printed. In this case, there exist some ink ejection ports that do not eject the ink. Moreover, there exist some ink ejection ports that eject ink but do not eject frequently (ink ejection ports ejecting ink infrequently).

    [0030] In this case, in the ink ejection port and the ink chamber, there is a possibility of ink drying to cause changes in ink viscosity.

    [0031] If the ink viscosity is changed in this manner, later, an intended amount of ink is not ejected in forming images by use of the ink ejection port, to be likely to lead to degradation of image quality.

    [0032] To describe further, in the printing method using the ink jet head, there exist ink ejection ports that do not perform ink ejection (hereinafter, referred to as "unused ink ejection ports") or ink ejection ports that eject ink infrequently (hereinafter, referred to as "low-frequency ink ejection ports"); in these ink ejection ports, there is a possibility of causing precipitation of compositions of ink, increase in ink viscosity, curing of ink or the like, and accordingly, the ink is less likely to be ejected.

    [0033] To describe more specifically, in the ink jet head, the ink filled into the ink jet head is supplied to the ink chamber provided to the ejection drive unit, such as the piezoelectric element, as described above, and the ink chamber is filled with the ink. In this case, if a state of not ejecting ink or a state of ejecting ink infrequently is continued in some ink chamber, there is a possibility that the ink is cured in the ink ejection port or in the ink chamber, and accordingly, an intended amount of ink is cannot be ejected.

    [0034] Moreover, in forming color images, the unused ink ejection ports or the low-frequency ink ejection ports are also generated.

    [0035] In general, ink used in color printing includes four colors of magenta, yellow, cyan and black. Moreover, white is used in response to the background color in some cases. Then, in forming the image, the color image is formed by overlapping the respective colors of ink.

    [0036]  In such an image forming mode, depending on an image to be formed, it is assumed that only a part of colors of ink is used; accordingly, in the inkjet print heads ejecting other colors of ink, the ink is likely to be cured.

    [0037] To suppress occurrence of the above-described inconvenience, in the exemplary embodiment, the above-described strip-shaped image OG is formed by use of the unused ink ejection ports or the low-frequency ink ejection ports.

    [0038] To additionally describe, in the exemplary embodiment, the ink is ejected from the unused ink ejection ports or the low-frequency ink ejection ports, and when the ejection is performed, the ink is made to be attached to the strip-shaped image formation region 152. Thus, ink clogging hardly occurs in the ink jet heads.

    [0039] Here, since the strip-shaped image OG is not a main image, it is preferable that the strip-shaped image OG is less conspicuous.

    [0040] As in the exemplary embodiment, when the strip-shaped image OG is provided along the axial direction of the can main body 110, the strip-shaped image OG becomes less conspicuous; therefore, a user tends to be less aware of the strip-shaped image OG. Consequently, in the exemplary embodiment, even though the strip-shaped image OG exists, damage to sense of beauty in the entire can body 100 is suppressed.

    [0041] FIG. 2 is a diagram showing the can body 100 subjected to printing by use of plate printing. To additionally describe, FIG. 2 is a diagram showing the can body 100 subjected to printing by use of a printing method now widely performed.

    [0042] In the plate printing, ink is transferred from a plate originating a print image to a blanket, and while the blanket to which the ink has been transferred is pressed against the outer circumferential surface 111 of the can body 100, the can body 100 or the blanket is rotated to perform printing onto the outer circumferential surface 111 of the can body 100.

    [0043] In the plate printing to the can body 100, normally, to prevent a blank from being generated in an image, one end and the other end in the circumferential direction of the image to be formed are overlapped. To additionally describe, in the plate printing to the can body 100, printing to the can body 100 is performed such that the strip-shaped image wraps around the can body 100; on this occasion, one end and the other and of the strip-shaped image are overlapped.

    [0044] In this case, as shown in FIG. 2, in the image formed on the outer circumferential surface 111, a strip-shaped image 200 is formed.

    [0045] Most of the can bodies 100 now being widely distributed are subjected to printing by the plate printing, and thereby the strip-shaped image 200 is formed on the can bodies 100 now being distributed. Then, since a user has many chances to see the strip-shaped image 200, the user gets used to the strip-shaped image 200. As a result, the strip-shaped image 200 becomes less conspicuous to the user.

    [0046] In the exemplary embodiment, the characteristics of the strip-shaped image 200 are used.

    [0047] If the ink is simply ejected from the unused ink ejection ports or the low-frequency ink ejection ports toward the main image MG on the outer circumferential surface 111, the image quality of the main image MG is degraded.

    [0048] To describe in detail, when the main image MG is formed on the outer circumferential surface 111, the main image MG is composed as an aggregate of dot-shaped inks on the outer circumferential surface 111. At this time, the types and arrangements of all individual dot-shaped inks, which serve as constructs, are determined in advance, and accordingly, the main image MG is formed on the outer circumferential surface 111 by arranging inks of the predetermined types at the predetermined positions on the outer circumferential surface 111 as dots. Therefore, arrangements of inks other than the predetermined types at the predetermined positions, such as simply ejecting ink from the unused ink ejection ports or the low-frequency ink ejection ports, result in damaging originally-intended quality of the main image MG, and accordingly, the image quality of the main image MG is degraded.

    [0049] In contrast thereto, in the exemplary embodiment, the ink is ejected to the strip-shaped image formation region 152 without being ejected to the main image MG.

    [0050] In this case, degradation in image quality of the main image MG is suppressed. Further, the strip-shaped image OG formed on the strip-shaped image formation region 152 resembles the strip-shaped image 200 formed in the above-described plate printing, and thereby the strip-shaped image OG is hardly recognized by a user and becomes less conspicuous.

    [0051] As another example, a mode can be considered in which waste cans (can bodies 100 not to be shipped as the products) are prepared and put into the printing apparatus, to thereby eject ink to the waste cans from the unused ink ejection ports or the low-frequency ink ejection ports.

    [0052] In this case, efforts are required to reclaim the waste cans. Moreover, the can bodies 100 to be discarded are generated, and accordingly, material losses occur.

    [0053] Here, the strip-shaped image OG may be formed on all of the can bodies 100, or the strip-shaped image OG may be formed every time the printing is performed on a predetermined number of can bodies 100.

    [0054] Moreover, the length and the width of the strip-shaped image OG are not particularly limited. In the example shown in FIG. 1, the length of the strip-shaped image OG (the length in the axial direction of the can main body 110) is assumed to be the same as the length of the main image formation region 151. Further, in the exemplary embodiment, the length of the strip-shaped image OG (the length in the axial direction of the can main body 110) is assumed to be the same length as the maximum length of the image printable on the can body 100 (the maximum length in the axial direction of the can main body 110).

    [0055] Moreover, to form the strip-shaped image OG, it is unnecessary to form the same strip-shaped image OG on all of the can bodies 100, and the strip-shaped image OG may be different in each can body 100.

    [0056] The printing by use of ink jet heads is usually digital printing; a process of differentiating the image in each can body 100 can be performed with ease in the digital printing.

    [0057] Further, it may be possible to differentiate the strip-shaped image OG in each can body 100, and further, to assign a story to each of the strip-shaped images OG. In this case, by preparing multiple can bodies 100, the entire story can be understood.

    [0058] Note that, in this case, the main image MG may serve as an image to complement the story, or may serve as an image to constitute a key for uncovering the story.

    [0059] FIGS. 3A and 3B are diagrams showing another configuration example of the can body 100. Note that FIG. 3A is a diagram viewing the can body 100 from diagonally above, and FIG. 3B is a front elevational view.

    [0060] In this configuration example, the strip-shaped image OG is divided, and the strip-shaped images OG are formed at two locations. Consequently, two strip-shaped images OG, namely, a first strip-shaped image OG1 and a second strip-shaped image OG2 are formed.

    [0061] Further, in this configuration example, the first strip-shaped image OG1 and the second strip-shaped image OG2 are formed at positions in the circumferential direction and in the axial direction of the can main body 110 that are different from each other.

    [0062] To additionally describe, in this configuration example, placement positions of the first strip-shaped image OG1 and the second strip-shaped image OG2 are deviated from each other in the circumferential direction and in the axial direction of the can main body 110.

    [0063] Further, in the exemplary embodiment, the first strip-shaped image OG1 and the second strip-shaped image OG2 overlap in the axial direction of the can main body 110.

    [0064] To describe further, in this configuration example, the first strip-shaped image OG1 and the second strip-shaped image OG2 are adjacent to each other in the axial direction of the can main body 110.

    [0065] Moreover, when the first strip-shaped image OG1 and the second strip-shaped image OG2 are projected in the circumferential direction of the can main body 110 as shown in FIG. 3B (when projection is performed onto a virtual projection surface extending along the axial direction of the can main body 110), an overlap is generated between the first strip-shaped image OG1 and the second strip-shaped image OG2.

    [0066] Here, when the overlap is not provided between the first strip-shaped image OG1 and the second strip-shaped image OG2 and a blank is generated therebetween, the ink cannot be ejected from the ink ejection port corresponding to the blank. In this case, if the unused ink ejection port or the low-frequency ink ejection port is positioned at a location corresponding to the blank, ink cannot be ejected from the unused ink ejection port or the low-frequency ink ejection port, and therefore, ink clogging is likely to occur in these ink ejection ports.

    [0067] On the other hand, when two strip-shaped images overlap as in the exemplary embodiment, occurrence of such an inconvenience can be suppressed.

    [0068] Note that, in FIG. 3, description has been given by taking a case in which two strip-shaped images are provided as an example; however, the number of strip-shaped images is not particularly limited and, for example, three strip-shaped images may be formed as shown in FIG. 4 (a diagram showing another arrangement example of the strip-shaped images).

    [0069] Here, in FIG. 4, the first strip-shaped image OG1 and a third strip-shaped image OG3 become the two strip-shaped images adjacent to each other in the axial direction, and an overlap is generated between the first strip-shaped image OG1 and the third strip-shaped image OG3 that are adjacent to each other in the axial direction.

    [0070] Moreover, the second strip-shaped image OG2 and the third strip-shaped image OG3 become the two strip-shaped images adjacent to each other in the axial direction, and an overlap is generated between the second strip-shaped image OG2 and the third strip-shaped image OG3.

    [0071] FIGS. 5A to 5E are diagrams illustrating details of the strip-shaped image OG.

    [0072] FIG. 5A shows the strip-shaped image formation region 152 on the outer circumferential surface 111 of the can main body 110. The strip-shaped image formation region 152 is formed in a rectangular shape.

    [0073] Note that the strip-shaped image formation region 152 is not limited to the rectangular shape as shown in FIG. 5A; the strip-shaped image formation region 152 may be in an oval shape, an elliptical shape, or a polygonal shape, such as a trapezoidal shape or a parallelogram shape.

    [0074] The ink is ejected into the inside of the strip-shaped image formation region 152, and thereby the strip-shaped image OG is formed.

    [0075] FIG. 5B shows an example of the strip-shaped image OG and exemplifies a case in which the strip-shaped image OG includes an image of a curved line.

    [0076] FIG. 5C exemplifies a case in which the strip-shaped image OG is composed of character images, which are images indicating characters. Specifically, a case in which the strip-shaped image OG is composed of multiple images each including multiple character images arranged in line in the axial direction of the can main body 110 is exemplified. Note that the character image is a concept including numeric characters.

    [0077] FIG. 5D exemplifies a case in which the strip-shaped image OG is composed of an image including multiple unit images being arranged (patterned design).

    [0078] FIG. 5E exemplifies a case in which the strip-shaped image OG is composed of diagonal lines.

    [0079] FIG. 6 is a diagram in which a part of the strip-shaped image OG shown in FIG. 5C is enlarged. Fig. 6 and Fig. 5C show a strip-shaped image prepared according to the printing method of the present invention.

    [0080] As described above, the strip-shaped image OG is composed of multiple images each including multiple character images arranged in line in the axial direction of the can main body 110. Further, in this configuration example, alphabetical characters are arranged.

    [0081] Here, when the strip-shaped image OG is formed to include the character image, it becomes possible to allow the strip-shaped image OG to have meaning. This makes it possible to allow the strip-shaped image OG to include, for example, a product name, a trade name or others.

    [0082] Further, in the configuration example shown in FIG. 6, character images arranged in the axial direction are in multiple rows (in the exemplary embodiment, provided in two rows).

    [0083] Further, each of the character images is arranged such that, between the character images that are positioned in a first row (one row) R1 and are adjacent to each other in the axial direction, a character image in a second row (the other row) R2 is positioned. To describe more specifically, between the two character images indicated by the signs 6A and 6B, the character image indicated by the sign 6C is positioned.

    [0084] To put it another way, in this configuration example, the character images are displayed in two rows, and the character images positioned in the second row are shifted by half a character with respect to the character images positioned in the first row.

    [0085] To describe further, in this configuration example, a character image positioned in one of the character image rows adjacent to each other is shifted by half a character with respect to a character image positioned in the other character image row.

    [0086] Consequently, in this configuration example, the blanks become less likely to be generated in the strip-shaped image OG, and similar to the above, it is possible to prevent the unused ink ejection ports or the low-frequency ink ejection ports from being positioned at the locations corresponding to the blanks.

    [0087] FIG. 7 is a diagram illustrating each pixel constituting the strip-shaped image OG.

    [0088] In FIG. 7, "B" indicates a pixel (dot) formed with black ink (B). "B1" indicates a pixel in black formed by overlapping the three colors of ink of cyan (C), magenta (M) and yellow (Y).

    [0089] "B2" indicates a pixel in black formed by overlapping the two colors of ink of black (B) and yellow (Y).

    [0090] "B3" indicates a pixel in black formed by overlapping the two colors of ink of black (B) and cyan (C).

    [0091] "B4" indicates a pixel in black formed by overlapping the two colors of ink of black (B) and magenta (M).

    [0092] In this example, the ranges X1, X2, X3, X4 and X5 are shown as a printing range and, in the ranges X1 to X5, pixels of B and B1 to B4 are connected to form a straight line.

    [0093] Moreover, though illustration is omitted, the straight lines are arranged in multiple rows in the circumferential direction of the can main body 110. Consequently, the strip-shaped image OG is formed.

    [0094] To put is another way, in this configuration example, the unused ink ejection ports or the low-frequency ink ejection ports eject the ink, not only one time, but multiple times, to thereby arrange the pixels in the circumferential direction of the can main body 110 to form the strip-shaped image OG.

    [0095] Here, in this configuration example, in the range X1, the main image MG is formed with the two colors of ink of cyan (C) and yellow (Y).

    [0096] Therefore, in the range X1, in forming the strip-shaped image OG, inks of black (B) and magenta (M), which are not used in forming the main image MG, are used (ejected).

    [0097] Moreover, in the range X2, the main image MG is formed with the two colors of ink of magenta (M) and yellow (Y). Therefore, in the range X2, inks of black (B) and cyan (C), which are not used in forming the main image MG, are used.

    [0098] Moreover, in the range X3, the main image MG is formed with the three colors of ink of cyan (C), yellow (Y) and magenta (M). Therefore, in the range X3, ink of black (B), which is not used in forming the main image MG, is ejected.

    [0099] Moreover, in the range X4, the main image MG is formed with the three colors of ink of cyan (C), magenta (M) and black (K). In the range X4, in forming the strip-shaped image OG, inks of black (B) and yellow (Y) are used.

    [0100] Here, in the range X4, the ink not used in forming the main image MG is yellow (Y) only; however, since yellow (Y) only cannot create the black color, the ink of, not only yellow (Y), but also black (B) is ejected in this configuration example. Note that it may be possible to create black by use of three colors of ink of yellow (Y), cyan (C) and magenta (M) without using black (B). However, in this case, costs of ink to be used is increased as compared to the case where only one color, black (B), is used.

    [0101] In the range X5, the main image MG is formed with ink of black (K). Therefore, in the range X5, in forming the strip-shaped image OG, the inks of cyan (C), yellow (Y) and magenta (M), which are not used in forming the main image MG, are used.

    [0102] Here, in the exemplary embodiment, as described above, the colors of pixels forming the strip-shaped image OG are made to be the same in forming the strip-shaped image OG.

    [0103] To additionally describe, the ink is ejected from, not only the unused ink ejection ports or the low-frequency ink ejection ports, but also ink ejection ports other than the unused ink ejection ports or the low-frequency ink ejection ports (normal ink ejection ports) as needed (for unifying colors). This reduces unevenness in colors of the strip-shaped image OG, and further makes the strip-shaped image OG less conspicuous.

    [0104] Note that there is a possibility that, in any of the ranges (part of ranges in the axial direction), the main image MG is formed by using four (all) colors of ink of cyan (C), yellow (Y), magenta (M) and black (K).

    [0105] In this case, in the part of ranges, in forming the strip-shaped image OG, for example, pixels are formed by using black (K) only. Alternatively, the black pixels are formed by using cyan (C), yellow (Y) and magenta (M).

    [0106] Moreover, as another example, in the above-described part of ranges, a mode can be considered in which the strip-shaped image OG is not formed. In this case, the strip-shaped image OG is formed not all the regions in the axial direction of the can main body 110, and blanks are generated in part of the strip-shaped image OG.

    [0107] FIGS. 8A and 8B are diagram showing an example of a printing apparatus 300 that performs above-described printing process. Note that FIG. 8A is a front elevational view and FIG. 8B is a side elevational view.

    [0108] The printing apparatus 300 is a so-called digital printer and performs printing onto the can body 100 based on image data.

    [0109] The printing apparatus 300 is provided with a motor M that rotates the can body 100 in the direction indicated by arrow 8A. Further, four ink jet heads H1, H2, H3 and H4 arranged radially around the can body 100 are provided.

    [0110] The four ink jet heads H1, H2, H3 and H4 eject inks of cyan (C), yellow (Y), magenta (M) and black (K), respectively.

    [0111] Further, the printing apparatus 300 is provided with a head control part 310 that is configured to include a program-controlled CPU and controls ejection of ink from the ink jet heads H1 to H4.

    [0112] As shown in FIG. 8A, each of the ink jet heads H1 to H4 is provided with an ink ejection port 330 that ejects ink to the can body. In each of the ink jet heads H1 to H4, multiple ink ejection ports 330 are provided and are arranged along the axial direction of the can body 100.

    [0113] Note that, in FIG. 8A, a case in which the ink ejection ports 330 are provided in a row in each of the inkjet heads H1 to H4 is exemplified; however, in each of the ink jet heads H1 to H4, the ink ejection ports 330 may be provided in multiple rows.

    [0114] In the exemplary embodiment, the four ink jet heads H1 to H4 are controlled by the head control part 310, and thereby the ink is ejected to the can body 100. Consequently, the above-described main image MG is formed.

    [0115] Further, the head control part 310 recognizes the unused ink ejection ports that are not used in forming the main image MG, and controls the inkjet heads H1 to H4 to cause the ink from the unused ink ejection ports to attach to the strip-shaped image formation region 152.

    [0116] More specifically, at the timing of when the strip-shaped image formation region 152 arrives at the location where the unused ink ejection port faces, the ink is made to be ejected from the unused ink ejection port.

    [0117] In this case, the can body to be an object of ink ejection from the unused ink ejection ports may be all of the can bodies 100, or it is possible to perform ejection every predetermined number of can bodies 100.

    [0118] Moreover, the head control part 310 recognizes the low-frequency ink ejection ports with a frequency of ink ejection lower than a predetermined frequency of ink ejection, and controls the ink jet heads H1 to H4 to cause the ink from the low-frequency ink ejection ports to attach to the strip-shaped image formation region 152.

    [0119] More specifically, at the timing of when the strip-shaped image formation region 152 arrives at the location where the low-frequency ink ejection port faces, the ink is made to be ejected from the low-frequency ink ejection port.

    [0120] In this case, as compared to the unused ink ejection ports, it is possible to perform a process of reducing the number of times of ink ejection or the like.

    [0121] By the above-described process, ink clogging at the unused ink ejection ports or the low-frequency ink ejection ports can be suppressed. Further, ink clogging in the ink chamber where the unused ink ejection ports or the low-frequency ink ejection ports are provided can be suppressed.

    Reference Signs List



    [0122] 
    100
    Can body
    110
    Can main body
    111
    Outer circumferential surface
    152
    Strip-shaped image formation region
    300
    Printing apparatus
    310
    Head control part
    330
    Ink ejection port
    H1, H2, H3, H4
    Inkjet head
    OG
    Strip-shaped image



    Claims

    1. A printing method to prepare a can body (100), the can body (100) comprising:
    can main body (110) that is formed cylindrically and includes an outer circumferential surface (111), and wherein on the outer circumferential surface (111) of the can main body (110), a main image (MG), which is a main image, and a strip-shaped image (OG) (200), which is a sub-image, are formed, wherein the main image (MG) is formed on a main image formation region (152) extending along the circumferential direction of the can main body (110), the strip-shaped image (200) is formed in a strip-shaped image formation region (152) formed in a rectangular shape and extending along the axial direction of the can main body (110) and the length of the strip-shaped image in the axial direction of the can main body (110) is the same length as the length of the main image formation region (152), and wherein the strip-shaped image (200) is formed from one end portion to the other end portion in the axial direction of the can main body (110) and in an entire region from the one end portion to the other end portion, wherein the strip-shaped image (200) is composed of multiple images adjacent to each other in the circumferential direction, each of said images forming a row including multiple character images arranged in line in the axial direction, and between character images that are positioned in one row and are adjacent to each other in the axial direction, a character image is positioned in another row by shifting the character image in the other row by half a character with respect to the character images in said one row, wherein the can body (100) is obtainable by a printing method comprising the following:
    a step of providing said can body (100); a main image formation step to form said main image, wherein ink of different colors from respective ink jet heads of a plurality of ink jet heads (H1, H2, H3, H4), each including a plurality of ink ejection ports (330), is ejected to the outer circumferential surface (111) of said can body (100), and wherein ink is ejected from the ink ejection port (330) corresponding to the image to be formed; a sub-image formation step to form said sub-image, wherein ink from the ink jet head (H1, H2, H3, H4) is ejected from at least one of an unused ink ejection port that is not used in forming the image and a low-frequency ink ejection port (330) with a frequency of ink ejection lower than a predetermined frequency of ink ejection, to said strip-shaped region.
     


    Ansprüche

    1. Druckverfahren zur Vorbereitung eines Dosenkörpers (100), wobei der Dosenkörper (100) umfasst:
    Dosenhauptkörper (110), der zylindrisch ausgebildet ist und eine Außenumfangsfläche (111) aufweist, und wobei auf der Außenumfangsfläche (111) des Dosenhauptkörpers (110) ein Hauptbild (MG), das ein Hauptbild ist, und ein streifenförmiges Bild (OG) (200), das ein Unterbild ist, ausgebildet sind, wobei das Hauptbild (MG) auf einem sich entlang der Umfangsrichtung des Dosenhauptkörpers (110) erstreckenden Hauptbilderzeugungsbereich (152) ausgebildet ist, das streifenförmige Bild (200) in einem Streifenbilderzeugungsbereich (152) ausgebildet ist, der in einer rechteckigen Form ausgebildet ist und sich entlang der axialen Richtung des Dosenhauptkörpers (110) erstreckt, und die Länge des streifenförmigen Bildes in der axialen Richtung des Dosenhauptkörpers (110) die gleiche Länge wie die Länge des Hauptbilderzeugungsbereichs (152) ist, und wobei das streifenförmige Bild (200) von einem Endabschnitt zum anderen Endabschnitt in der axialen Richtung des Dosenhauptkörpers (110) und in einem gesamten Bereich von dem einen Endabschnitt zum anderen Endabschnitt gebildet wird, wobei das streifenförmige Bild (200) aus mehreren in Umfangsrichtung nebeneinander liegenden Bildern zusammengesetzt ist, wobei jedes der Bilder eine Reihe bildet, die mehrere Zeichenbilder enthält, die in der axialen Richtung in einer Reihe angeordnet sind, und zwischen Zeichenbildern, die in einer Reihe positioniert sind und in axialer Richtung nebeneinander liegen, ein Zeichenbild in einer anderen Reihe positioniert ist, indem das Zeichenbild in der anderen Reihe um ein halbes Zeichen in Bezug auf die Zeichenbilder in der einen Reihe verschoben ist, wobei der Dosenkörper (100) durch ein Druckverfahren erhalten werden kann, das Folgendes umfasst:
    einen Schritt des Bereitstellens des Dosenkörpers (100); einen Hauptbilderzeugungsschritt, bei dem Tinte unterschiedlicher Farben von jeweiligen Tintenstrahlköpfen einer Vielzahl von Tintenstrahlköpfen (H1, H2, H3, H4), von denen jeder eine Vielzahl von Tintenausstoßöffnungen (330) aufweist, auf die äußere Umfangsfläche (111) des Dosenkörpers (100) ausgestoßen wird, und bei dem Tinte von der Tintenausstoßöffnung (330) entsprechend dem zu erzeugenden Bild ausgestoßen wird; einen Unterbilderzeugungsschritt, bei dem Tinte aus dem Tintenstrahlkopf (H1, H2, H3, H4) aus einer unbenutzten Tintenausstoßöffnung, die nicht bei der Erzeugung des Bildes verwendet wird, und/oder aus einer Niederfrequenz-Tintenausstoßöffnung (330) mit einer Tintenausstoßfrequenz, die niedriger als eine vorbestimmte Tintenausstoßfrequenz ist, in den streifenförmigen Bereich ausgestoßen wird.
     


    Revendications

    1. Procédé d'impression pour préparer un corps de boîte (100), le corps de boîte (100) comprenant:
    un corps de boîte principal (110) qui est formé de façon cylindrique et qui présente une surface circonférentielle extérieure (111), et dans lequel sur la surface circonférentielle extérieure (111) du corps de boîte principal (110), une image principale (MG), qui est une image principale, et une image en forme de bande (OG) (200), qui est une image secondaire, sont formées, dans lequel l'image principale (MG) est formée sur une région de formation d'image principale (152) qui s'étend le long de la direction circonférentielle du corps de boîte principal (110), l'image en forme de bande (200) est formée dans une région de formation d'image en forme de bande (152) qui est de forme rectangulaire et qui s'étend le long de la direction axiale du corps de boîte principal (110), et la longueur de l'image en forme de bande dans la direction axiale du corps de boîte principal (110) est la même longueur que la longueur de la région de formation d'image principale (152), et dans lequel l'image en forme de bande (200) est formée à partir d'une première partie d'extrémité jusqu'à l'autre partie d'extrémité dans la direction axiale du corps de boîte principal (110) et dans une région entière à partir de ladite première partie extrémité jusqu'à l'autre partie d'extrémité, dans lequel l'image en forme de bande (200) est composée de multiples images adjacentes les unes aux autres dans la direction circonférentielle, chacune desdites images formant une rangée contenant de multiples images de caractère agencées en ligne dans la direction axiale, et entre des images de caractère qui sont positionnées dans une première rangée et qui sont adjacentes les unes aux autres dans la direction axiale, une image de caractère est positionnée dans une autre rangée en décalant l'image de caractère dans l'autre rangée d'un demi-caractère par rapport aux images de caractère dans ladite première rangée, dans lequel le corps de boîte (100) peut être obtenu par un procédé d'impression comprenant:

    une étape de fourniture dudit corps de boîte (100);

    une étape de formation d'image principale pour former ladite image principale,

    dans lequel une encre de couleur différente en provenance de têtes à jet d'encre respectives d'une pluralité de têtes à jet d'encre (H1, H2, H3, H4), qui comportent chacune une pluralité d'orifices d'éjection d'encre (330), est éjectée en direction de la surface circonférentielle extérieure (111) dudit corps de boîte (100), et

    dans lequel une encre est éjectée à partir de l'orifice d'éjection d'encre (330) qui correspond à l'image à former;

    une étape de formation d'image secondaire pour former ladite image secondaire,

    dans lequel une encre en provenance de la tête à jet d'encre (H1, H2, H3, H4) est éjectée à partir d'au moins un orifice d'éjection d'encre inutilisé qui n'est pas utilisé pour former l'image et d'un orifice d'éjection d'encre à basse fréquence (330) dont la fréquence d'éjection d'encre est inférieure à une fréquence d'éjection d'encre prédéterminée, sur ladite région en forme de bande.


     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description