JP3469844B2 - A printing method using a printing system with high chroma and excellent color reproducibility in the specified color portion - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, printing of a packaging material, etc.
Process printing with conventional red ink, yellow ink, indigo ink, and black ink, and the designated color part (for example, solid print part) that requires high saturation is orange to red ink, green ink and Add one of the purple inks,
[Red ink, orange-red ink, α], [Orange-red ink, yellow ink, α], [Yellow ink, green ink, α], [Green ink, indigo ink, α], [Indigo ink, purple ink] , Α],
Print with any of [purple ink, red ink, α] (α is one of black ink, yellow ink, and indigo ink that is in the complementary color position with the specified color with the specified color) As a result, the present invention relates to a printing method that enables color reproduction even when the designated color has high saturation.

[0002]

2. Description of the Related Art For example, when printing a packaging material, a photographed image and a designated color portion such as a logo (for example, a solid printed portion) are mixed, and the designated color portion often has a product name or a catch copy. Color is often used. In the case of printing this designated color portion, conventionally, a special color ink toned and mixed with a specific ink is used. The use of such features inks, it shall be to produce a spot color inks for each document, with grossly efficiency of fall is currently the processing of cleaning and residual ink in the ink supply portion of the printing device is there. In addition, printing with multi-color separation for color reproduction of high-saturation colors increases the number of plates, costs plate making, and complicates color adjustment of photographic image parts, making it a high-value-added printed matter. It remains to be adapted.

[0003]

In consideration of actual operation, when all the parts of the original are reproduced by multicolor printing, 5 to 6 color inks are used even in the parts where the conventional four primary colors can be sufficiently reproduced. As a result, the fine adjustment process for color reproduction becomes complicated, which causes an increase in printing cost. In the case of packaging materials, photographic images have conventionally been made with three-color ink and black ink, and the image quality has been sufficiently satisfied by customers. What the customer wants is the color reproduction of the designated color portion of the high-saturation color used for the product name and catch phrase.

In the case of offset printing and gravure printing, a wide range of color reproduction is performed by using both subtractive color mixing and side-by-side color mixing, but since the three primary colors of printing ink do not have an ideal spectral reflectance distribution, color reproduction is possible. The range is limited, and color reproduction of highly saturated colors, especially in the intermediate hues of the three primary colors, is insufficient. Therefore, an object of the present invention is to solve the above-described drawbacks and to easily reproduce a color of an original including a designated color portion of high saturation simply as the original without using a special color ink for each original. It is to provide a printing method.

[0005]

Therefore, in the present invention, for example, when a document is composed of a photographic image portion B and a highly saturated designated color portion A, it is separated into a photographic image portion B and a highly saturated designated color portion A. B is reproduced by process printing with red ink, yellow ink, indigo ink, and black ink, and A is one of orange-red ink, green ink, and purple ink whose hue is close to the specified color for each specified color. One of the above, and one of the above-mentioned red ink, yellow ink, and indigo ink that is adjacent to the position where the specified color can be sandwiched by the hue circle, and is printed with a combination that includes high-saturation color reproduction in the specified color part. To provide a printing method using a printing system having excellent properties.

Here, the above-mentioned "combination" means [red ink, orange-red ink, α], [orange-red ink, yellow ink,
α], [yellow ink, green ink, α], refers to the [green ink, indigo ink, α], [indigo ink, violet ink, α], [purple ink, red ink, α], α is, those of the One of red ink, yellow ink, and indigo ink, which are complementary colors in the designated color and hue circle. It is not necessary to align three orange-red inks, green inks, and purple inks, but add one for each designated color. The "hue circle" is shown in FIG.

Further, in the present invention, in producing a color separation plate, the above A is color separated for the above combination, and the color separation information for red ink, yellow ink, indigo ink and black ink is B It is combined with the color separation information for red ink, yellow ink, indigo ink, and black ink, which is the color separation of the part of A, and when color reproduction (printing) of B is completed, a part of the color reproduction of the part of A is completed. Provide a printing method.

When the ink used in the present invention is printed on white paper or a white plastic film preprinted with white ink with 100% halftone dots, it is displayed by the JIS Z8721 color display method (display by three attributes). However, with red ink, 3RP-6R / 3.6-5.2 / 10.0 or more,
With yellow ink, 5Y-10Y / 8.2-9.4 / 10.0
Above, with indigo ink, 5B-3PB / 3.0-5.6 / 1
0.0 or more, black ink, V is 2.0 or less, C is 1.0 or less, orange to red ink, 8R to 5YR / 5.2 to 7.0 /
10.0 or more, with green ink, 1G to 3BG / 4.5 to
6.9 / 10.0 or more, purple ink, 8PB-8P /
Within the range of 0.7 to 4.0 / 10.0 or more, and the main component dye of the printing ink is red ink, and the orange to red ink is a red dye, an orange dye, a yellow dye, or a mixture thereof, Yellow ink is yellow pigment, green ink, indigo ink is green pigment, blue pigment, yellow pigment single or mixture thereof, purple ink is purple pigment, red pigment, blue pigment single or mixture thereof, and black ink is black pigment. Or a mixture of three or more chromatic colors, and among these seven color inks, in addition to red ink, yellow ink, indigo ink and black ink, orange to red ink, green ink,
5 colors including at least one selected from purple ink
A printing method using a 7-color ink set is provided.

According to the present invention, for example, when the original is a photographic image and a designated color of high saturation, the original is separated into a photographic image portion and a designated color portion of high saturation, and the photographic image portion is formed by conventional red ink or yellow ink. , By printing overprinting of indigo ink and black ink, and by printing at least one color selected from orange to red ink, green ink and purple ink for the designated color part, by printing with one of the above combinations Get high saturation color reproduction. By adopting the printing method according to the present invention, the designated color required by the customer can be dealt with without using the special color ink of the conventional method, so that the economical effect is large.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. Examples of the red dye used in the present invention include Pigment Red (PR)
2, P.I. R. 3, P.I. R. 4, P.P. R. 5, P.I. R.
6, P. R. 7, P. R. 8, P. R. 9 , P. R. 1
0, P. R. 14, P.I. R. 34, P.I. R. 37, P.I.
R. 38, P.I. R. 48: 1, P.I. R. 48: 2, p.
R. 48: 3, p. R. 48: 4, p. R. 53 : 1,
P. R. 57 : 1, P.I. R. 68, P.P. R. 104,
P. R. 112, P.I. R. 114, P.I. R. 122,
P. R. 123, P.I. R. 144, P.I. R. 146,
P. R. 147, P.I. R. 149, P.I. R. 150,
P. R. 151, P.I. R. 168, P.I. R. 170,
P. R. 171, P.I. R. 175, P.I. R. 177,
P. R. 184, P.I. R. 185, P.I. R. 187,
P. R. 188, P.I. R. 194, P.I. R. 208,
P. R. 209, P.I. R. 210, P.I. R. 220,
P. R. 221 and P.221. R. 222, P.I. R. 224,
P. R. 245, P.P. R. 254 and the like.

Examples of the yellow dye include pigment yellow (P.Y.) 1 , P. Y. 3, P.I. Y. 12, P.I.
Y. 13, P.I. Y. 14, P.I. Y. 16, P.I. Y. 1
7, P. Y. 24, P.I. Y. 34, P.I. Y. 55, P.I.
Y. 74, P.I. Y. 81, P.I. Y. 83, P.I. Y. 9
3, P.I. Y. 94, P.I. Y. 95, P.I. Y. 109,
P. Y. 110, P.I. Y. 113, P.I. Y. 120,
P. Y. 123, P.I. Y. 128, P.I. Y. 147,
P. Y. 151, P.I. Y. 154, P.I. Y. 160,
P. Y. 167, P.I. Y. 193 and the like.

Examples of orange dyes include Pigment Orange (PO) 5 and P.O. O. 13, P.I. O. 16,
P. O. 31, P.I. O. 34, P.I. O. 36, P.I. O.
38, P.I. O. 43, P.P. O. 61, P.I. O. 64 etc. are mentioned. Examples of the cyan dye include P.I. B. 1
5: 1, P. B. 15: 2, p. B. 15: 3, p.
B. 15: 4, p. B. 15: 6, p. B. 56, P.I.
B. 60, P.I. B. 61 etc. are mentioned.

Examples of green dyes include Pigment Green (PG) 7, P.G. G. 13, P.I. G. 36 and the like. Examples of purple pigments include Pigment Violet (P.V.) 19, P.I. V. 23, P.I.
V. 32, P.I. V. 37, P.I. V. 5 0, and the like. Examples of black dyes include pigment black (P.Bk.) 1, P.I. Bk. 6, P. Bk. 7, P.
Bk. Mixtures of chromatic pigments black pigments or the above said three colors, such as 11 and the like. The vehicle used for the above ink may be the same as the one widely used in the related art, and each ink is manufactured by a conventionally known method.

When the above-mentioned printing method is used for the designated color portion included in the original, any one of red ink, yellow ink, indigo ink, and black ink is included, but the designated color portion and the other are positionally different. Therefore, the designated color part is
Select one that can be included in the color space from the two types, and select the red ink, yellow ink, and
Plates for indigo ink and black ink can be incorporated into plates for colors other than the designated color. A plate for at least one color ink of orange to red ink, green ink, and purple ink in the above-mentioned selected three color combinations is newly prepared.

In the present invention, when selecting three colors, the method of selecting colors is to apply three primary colors of light of red, green and blue-violet, and shift the three primary colors to either side on the hue circle to select three colors. A method of selection can be considered. As a result, there are 6 colors that can be selected, and the range of color development is expanded.

In the printing method of the present invention for the designated color portion, one color expression system is constituted by a maximum of seven color set inks. This color system can be expressed as a color solid having a dodecagonal pyramid with the halftone dot density of black ink as the vertical axis, or a star-shaped pyramid of David depending on the expression method (see FIG. 2).

In this three-dimensional shape, the lightness gradually increases toward the center around the surrounding highly saturated colors, and a clear color area that converges to the central white point (paper color) is provided at the top and the achromatic axis is set. The same black level color planes in which the black dot level gradually increases toward the bottom are piled up, and as the black ink dot density increases, the area of the same black level color plane decreases, and eventually, at 100% black. Converges to 1 point.

In this three-dimensional shape, two adjacent hues are used.
Since the intermediate color is expressed by the overprinting of one ink, the color reproducibility is expanded because there is little turbidity of the color caused by the overprinting of the conventional red ink, yellow ink, indigo ink and black ink. This three-dimensional shape is a color system in which the hues are defined only by the three factors of the two-color inks adjacent to each other and the halftone dot density of the black ink. Therefore, the display of one color is represented by three kinds of symbol amounts. Examples are [100% red, 0% orange, 0% black], [50% orange, 50 yellow]
%, Black 0%], [green 80%, indigo 20%, black 10%], etc.

The present invention can be applied to all printing methods such as gravure printing, offset printing, etc., but the basics of the method are the same. explain.

[0020]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. A polyethylene terephthalate (PET) film having a thickness of 12 μm is preprinted with white ink and then with color ink. The surface (solid surface) printed with 100% halftone dots is the primary color, and the solid surface obtained by overprinting 100% halftone dots of two inks with adjacent hues is the secondary color.

FIGS. 3 and 4 show the spectral reflection curves of the seven primary colors of ink of the system of the present invention when gravure printing is performed under the above conditions. Four of these colors are the same as those of normal process inks, and it can be said that the closer the reflectance is to 100%, the brighter the color, and the sharper the shape, the more vivid and clear the color.

Table 1 shows the Munsell value, the dominant wavelength and the color purity of the solid printing surface of the seven-color printing ink of the present invention and the solid overprinting surface of the adjacent two chromatic color inks.
Table 2 shows the Munsell value, the dominant wavelength, and the color purity of the solid overprinted surface of the two conventionally used chromatic color inks. What is plotted on the drawing is shown in FIG. 5, and it can be seen that the system of the present invention (solid line) has a wider color development range as compared with the case of normal four-color process printing (dotted line). In this figure, it can be said that the color is more saturated toward the outside.

[0023]

[0024]

The inks used in this example are shown in Table 3.

From these tables, it is clear that the printing method of the present invention can print more saturated colors or higher purity colors than the conventional four-color process printing. Further, in general four-color process printing, plate making and printing are performed at different screen angles for each color, and screen angles of 0 °, 15 °, 45 °, and 75 ° are used as limits for preventing moire.

Since a maximum of seven colors of printing ink are used in this system, it is ideal to use seven screen angles, but this causes moire. Although some ingenuity is required for plate making, since the designated color portion is a color reproduction system with a maximum of three colors using two adjacent colors and black or complementary chromatic color ink, moire does not occur.

[0028]

According to the method of the present invention, printing inks of seven colors, whose chromaticity by the XYZ color system falls within a specific range,
That is, red ink, orange-red ink, yellow ink, green ink,
Printing that reproduces color by using indigo ink, purple ink, and black ink, and overlapping two chromatic color inks and three black inks adjacent to each other on the color wheel Because it is a method, the traditional yellow, crimson,
There is an advantage that high saturation color expression can be achieved as compared with the method of overprinting indigo three primary color inks and supplementarily using black ink.
Therefore, particularly in printing of packaging materials, the designated color portion having many highly saturated colors can be formed by the process printing without using the conventional special color ink, which is extremely economically effective.

[Brief description of drawings]

FIG. 1 shows a positional relationship on a hue circle of six primary color printing inks, so that a combination of adjacent two or three colors and an opposite color are clear.

FIG. 2 shows a shape-color solid of a color space that can be represented by the printing method of the present invention.

FIG. 3 shows yellow ink, red ink, and orange ink used in the present invention.
The spectral reflectance curve of the solid printing surface of red ink and green ink is shown.

FIG. 4 shows spectral reflectance curves of solid printing surfaces of indigo ink, purple ink and black ink used in the present invention.

FIG. 5 is a hue-saturation graph of Munsell chromaticity, and a solid line shows the hue / saturation expressed by the solid printing surface of the seven-color printing ink of the present invention and the adjacent two-color chromatic ink. The dotted line shows that of the four-color process printing ink conventionally used.

[Explanation of symbols]

M: Red ink O: Orange to red ink Y: Yellow ink G: Green ink C: Indigo ink V: Purple ink B: Black ink

(72) Inventor Hiroshi Nakano 1-7-6 Nihonbashi Bakurocho, Chuo-ku, Tokyo Within Dainichi Seika Kogyo Co., Ltd. (72) Inventor Fumiyoshi Saito 1-7-6 Nihonbashi-Bakurocho, Chuo-ku, Tokyo Nissei Chemical Industry Co., Ltd. (72) Inventor Atsushi Kobayashi 1-7-6 Nihonbashi Bakurocho, Chuo-ku, Tokyo Daiichi Seika Chemical Industry Co., Ltd. (56) Reference JP-A-2-32890 (JP, A) HEI 7-81205 (JP, A) "Printing ink handbook", Japan, Printing ink industry association, June 1978, pp.146-149 and 152-155 "8-color printing gravure system", Japan, Dainichi Seika Kogyo Co., Ltd., pp. 1-10 (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41M 1/14

Claims (2)

(57) [Claims] 1. When a document including a designated color with high saturation is reproduced by printing, the high-saturation color reproduction portion is designated as A, and A
If the other part is B, B is reproduced by process printing with red ink, yellow ink, indigo ink and black ink, and A is orange-red ink, green with a hue similar to the specified color for each specified color. One of ink and purple ink, and the above-mentioned red ink,
Printing using a printing system with high color saturation and excellent color reproducibility in the designated color part, which is characterized by printing with a combination including one of the yellow ink and the indigo ink that is adjacent to the position where the designated color can be sandwiched by the hue circle. Method. (Here, the “combination” means [red ink, orange-red ink, α], [orange-red ink, yellow ink, α], [yellow ink, green ink, α], [green ink, indigo ink] ,
α], [indigo ink, violet ink, α], [purple ink, red ink, refers to α], α is, red ink is in the complementary color of the position in this the designated color and the hue ring, yellow ink, of indigo ink One of them. It is not necessary to align three orange-red inks, green inks, and purple inks, but add one for each designated color.
The "hue circle" is shown in FIG. ) 2. When printed on a white plastic film or a white plastic film preprinted with white ink with 100% halftone dots, the display according to the JIS Z8721 color display method (display by three attributes) is red ink from 3RP to 6R / 3.6-5.2 / 10 or more, yellow ink 5Y-10Y / 8.2-9.4 / 10 or more, indigo ink 5B-3PB / 3.0-5.6 / 10 or more Ink ink, V is 2.0 or less, C is 1.0 or less, and orange to red ink is 5R to 5YR / 5.2 to 7.0 / 10
As described above, the green ink is in the range of 1G to 3BG / 4.5 to 6.9 / 10 and the purple ink is in the range of 8PB to 8P / 0.7 to 4.0 / 10 and the printing ink Main component dye is red ink, orange-red ink is red dye, orange dye, yellow dye single or mixture thereof, yellow ink is yellow dye, green ink, indigo ink is green dye, blue dye, yellow dye single Or a mixture thereof, a purple ink is a single or a mixture of a purple pigment, a blue pigment and a red pigment, a black ink is a black pigment or a mixture of three or more chromatic colors, and among these seven color inks, a red ink, The printing according to claim 1, wherein an ink set of 5 to 7 colors including at least one selected from orange to red ink, green ink and purple ink in addition to yellow ink, indigo ink and black ink is used. Method.