WO2007099665A1

WO2007099665A1 - Offset printing method

Info

Publication number: WO2007099665A1
Application number: PCT/JP2006/319800
Authority: WO
Inventors: Michio Yabuno; Takeshi Sasaki; Hidenori Shiraishi; Takeshi Tutiya; Hiroshige Asai; Satoshi Washio
Original assignee: Toyo Ink Mfg. Co., Ltd.
Priority date: 2006-03-03
Filing date: 2006-10-03
Publication date: 2007-09-07

Abstract

An offset printing method using an ink selected from yellow, red, indigo, and black inks, characterized in that the L*a*b* values of yellow, red, and indigo inks of when they are singly solid-printed with their standard density values on a newspaper Japan color standard paper conforming to the ISO standards and the L*a*b* values of the inks of when each set of two of the inks are solid-overprinted with the standard density values are in the following respective ranges. Their standard density values of the yellow, red, indigo inks are 0.85 to 0.95, 0.88 to 1.00, and 0.84 to 1.00, respectively. The L*, a*, and b* values of the yellow ink are 75 to 85, 0 to -10, and 60 to 70; those of the red one are 52 to 62, 46 to 56, and -5 to -15; and those of the indigo one are 52 to 62, -20 to -30, and -24 to -34, respectively. The L*, a*, and b* values of the red-yellow ink overprinting are 50 to 60, 37 to 50, and 27 to 37; those of the indigo-yellow ink overprinting are 50 to 60, -35 to -45, and 16 to 26; and those of the indigo-red ink overprinting are 35 to 45, 10 to 20, and -30 to -40, respectively.

Description

Specification

Offset printing method

Technical field

The present invention relates to an offset printing method using process four-color inks of yellow, red, indigo and black. The present invention also relates to an offset printing ink set comprising four process inks of yellow, red, indigo and black.

Background art

[0002] The IT revolution that began in the 90s has rapidly led the environment surrounding the printing field in the direction of digitality. The workflow of the conventional printing system is also a lot of process power such as shooting 'positive' scanning 'data · design · EPS (Encapsulated Post Script) · imposition · film · printing plate · printing. On the other hand, the workflow of digitized printing system also has process powers such as digital camera shooting, DTP (Desk Top Publishing), CTP (Computer To Plate) 'printing. Digital printing has succeeded in dramatically shortening the printing workflow compared to conventional printing methods. In addition, digitalization is making “RGB” submission data a standard, and the data being handled is changing to a wider color reproduction range.

[0003] However, at present, lithographic offset printing, which is the mainstream of printing, uses process inks of four colors (CMYK): yellow ink, red ink, indigo ink, and black ink. Therefore, in order to perform lithographic offset printing, data submitted as “RGB” must be color-converted (color separation) into “CMYK”. Process Hue is expressed by subtractive color mixing in printed materials using four-color inks, so the hue becomes turbid each time the colors are overlapped, and the color reproduction area is inevitably narrower than that of “RGB”. In addition, color reproduction will not be successful unless the color space at the shooting stage is set or the final color conversion from “RGB” to “C MY:” is not performed properly. Thus, the difference in color reproducibility between “RG B” digital data and printed matter using process four-color (CMYK) ink is a problem.

[0004] In particular, in paper-repellent printing (especially newspaper printing) using penetrating dry ink, there are problems of paper whiteness and smoothness, and the color reproduction region is further narrower than that for coated paper. This As a result, the difference in color reproducibility between the sample prints of “RGB” digital data and the reprints becomes a serious problem.

In general, in order to widen the color reproduction region, it is necessary to make the spectral reflectance curve of each color close to the ideal spectral reflectance curve. In other words, people recognize colors 400ηπ! In the wavelength range of ~ 700ηm (this wavelength is called visible light), it is said that the ideal reflectance for yellow ink, red ink, and indigo ink is as follows. . Figure 1 shows the ideal spectral reflectance curve for process inks.

• Yellow ink: 100% reflectivity in the wavelength range from 500nm to 700nm, 0% reflectivity in the wavelength range from 400nm to 500nm

• Red ink: 100% reflectivity in the wavelength range of 400nm to 500nm and 600nm to 700nm, reflectivity power S0% in the wavelength range of 500nm to 600nm

• Indigo ink: 100% reflectivity in the wavelength range from 400nm to 600nm, 0% reflectivity in the wavelength range from 600nm to 700nm

[0006] In the ink set for offset printing, which has the four-color process of yellow, red, indigo and black, the reflection spectrum of each ink is different from the ideal reflection spectrum. The color reproducibility is narrowed because there is a large absorption in the wavelength range where the light must be completely reflected, that is, there is a component that causes ink turbidity.

[0007] Also, in particular, when yellow ink printed as the final color is opaque, yellow fog appears, and this has a large effect on each color of underprint. It makes it difficult to reproduce the data. Therefore, it is desirable that the yellow ink is as transparent as possible, and can produce secondary and tertiary colors without turbidity when overprinted with other colors.

[0008] On the other hand, when printing on a renewal paper such as newsprint with inferior whiteness, it is desirable that it is opaque without being affected by the lower paper. If it is opaque, it can exhibit the original color developability of yellow ink, and a wide color reproduction region can be obtained.

As means for solving these problems, Japanese Patent Application Laid-Open No. 2001-260516 discloses a printing method using an ink set of 5 to 7 colors as a printing method for obtaining a printed matter with high saturation. In this printing method, as an ink set, an ink set consisting of 6 colors (hexachrome printing) with orange and green in the process 4 colors, and 7 colors with orange, green and purple in the process 4 colors (Ha Ink sets, etc., which have the ability to print) are used. For Hexachrome printing, not only primary colors but also secondary and tertiary colors are suppressed, and as a means to expand the color reproduction range, some color inks contain fluorescent pigments, etc. The method is taken. However, when this method is used, if printability is deteriorated (transfer defect, gloss reduction, etc.), the printed matter is faded due to insufficient light resistance. In addition, these methods require an expensive multicolor printing machine in which the number of ink colors used is 6 or 7 and the number of cylinders of the printing machine is 6 or more, and more than 6 plates. Requires a color-separated version. Therefore, in order to start these methods anew, huge capital investment and complex color management are required, so it is limited to a limited range.

Disclosure of the invention

[0010] The present invention has been made to solve any of the problems in the conventional technology. That is, an object of the present invention is to provide an offset printing method that can reproduce a color rendering area by “RGB”, which is a printing method using a widely used four-color printer. Another object of the present invention is a printing method using a four-color printing machine, which has been widely used in the past, when the yellow fog phenomenon is suppressed and yellow ink is overprinted with other color inks. It is to provide an offset printing method capable of obtaining secondary and tertiary colors without turbidity. Alternatively, another problem of the present invention is a printing method using a four-color printing machine that has been widely used in the past, and when printing on a sheet of paper, the original color developability is not affected by the lower sheet. The present invention provides an offset printing method capable of reproducing a wide color rendering region by using a yellow ink indicating the above. Still another object of the present invention is to provide an ink set and ink that can be preferably used in these printing methods, and to provide a printed matter printed by these printing methods.

[0011] In order to solve the above problem!

[0012] The present invention is an offset printing method using an ink in which yellow, red, indigo and black ink strengths are also selected. L * a * b * values of each color when printed with a solid density alone, and two colors selected with yellow, red, and indigo ink strengths when each color is overprinted with a standard density value. L * a * b * value of the following is within the following range, using yellow, red and indigo ink The present invention relates to an offset printing method. Here, the standard density values are yellow 0.85--0.95, red 0.88-1.00, indigo 0.84-84: L 00: L water a water b water value ί or yellow ink L water: 75 to 85, a water: 0 to 10, b water: 60 to 70; red ink L water: 52 to 62, a water: 46 to 56, b water: 5 to 15; Indigo ink L * : 52 ~ 62, a *: -20 ~ 30, b *: -24 ~ 1 34; Red and yellow ink printing L *: 50 ~ 60, a *: 37 ~ 50, b *: 27 ~ 37 Overprinting of indigo and yellow ink L *: 50-60, a *: -35 to 45, b *: 16-26; Overprinting of indigo and red ink L *: 35-45, a Water: 10- 20, b water: 30 to 40.

[0013] Another aspect of the present invention relates to an ink set for offset printing characterized by comprising the following yellow, red and indigo inks, and black ink.

As a disazo yellow compound, CI Pigment Yellow 12 or C. I Pigment Yellow 13 is contained in an amount of 5 to 15% by weight with respect to the total weight of the ink. Yellow ink with L * value of 31 or less when solid ink is printed with a density value of 0.85-0.95.

Red ink containing 15 to 20% by weight of C. I. Pigment Red 81, C. I Pigment Violet 1 or C. I. Pigment Red 169 as a metal lake compound of a rhodamine dye based on the total weight of the ink.

CI Pigment Blue 15: 3 or CI Pigment Blue 15: 4 as the phthalocyanine compound is 10 to 25% by weight based on the total weight of the ink, and CI Pigment Green 7 is added to the total weight of the ink if necessary. against 0.5 to 2.0 weight ^_0/0 containing the indigo ink.

[0014] Still another aspect of the present invention relates to an offset printing ink set comprising the following yellow, red and indigo inks, and black ink.

As a disazo yellow compound, CI Pigment Yellow 12 or C. I Pigment Yellow 13 is contained in an amount of 5 to 15% by weight with respect to the total weight of the ink. Yellow ink with a L * value of 31 or more when solidly printed with a density of 0.85-0.95.

Crimson ink containing CI Pigment Red 81, CI Pigment Violet 1 or CI Pigment Red 169 as a metal lake compound of rhodamine dyes in an amount of 15 to 20% by weight based on the total weight of the ink. CI Pigment Blue 15: 3 or CI Pigment Blue 15: 4 as the phthalocyanine compound is 10 to 25% by weight based on the total weight of the ink, and CI Pigment Green 7 is added to the total weight of the ink if necessary. against 0.5 to 2.0 weight ^_0/0 containing the indigo ink.

[0015] Still another aspect of the present invention relates to an offset printing ink set comprising the following yellow and red inks, and indigo and black inks.

When the maximum reflectance in the wavelength region of 400 nm to 700 nm is 100%, the reflectance in the wavelength region of 400 ηm to 480 nm is 1 to 20%, and the reflectance in the wavelength region of 530 nm to 700 nm is 90 to 100%. Is yellow ink.

When the maximum reflectance in the wavelength region of 400 nm to 700 nm is 100%, the maximum reflectance in the wavelength region of 400 ηm to 500 nm is 50% to 100%, and the reflectance in the wavelength region of 500 nm to 560 nm is 1 to A red ink that is 20% and has a reflectance of 90% to 100% in the wavelength region of 630 nm to 700 nm.

[0016] Still another aspect of the present invention relates to an offset printing ink set comprising the following yellow and red inks, and indigo and black inks.

When the maximum reflectance in the wavelength region of 400 nm to 700 nm is 100%, the reflectance in the wavelength region of 400 ηm to 500 nm is 10% or more, and the reflectance in the wavelength region of 530 nm to 700 nm is 90 to 100%. Is yellow ink.

[0017] Still another aspect of the present invention relates to an ink set used in the offset printing method. Yet another aspect of the present invention relates to a printed matter printed by the lithographic printing method, or a printed matter printed using the ink set or ink.

[0018] The disclosure of the present application was filed on March 3, 2006, Japanese Patent Application Nos. 2006-057481, 2006-057482, and 2006-055743, filed on March 31, 2006. Japanese Patent Application No. 2 006— 099159, Japanese Patent Application No. 2006—102498 filed on April 3, 2006, and Japanese Patent Application No. 2006—102503, along with Japanese Patent Application No. 2006, September 27, 2006 — 26360 No. 6 and Japanese Patent Application No. 2006-263607, along with the subject matter described in Japanese Patent Application No. 200 6-267389 filed on September 29, 2006. Incorporated.

Brief Description of Drawings

[0019] FIG. 1 is an ideal spectral reflection curve of each color ink.

[FIG. 2] FIG. 2 is an a * b * two-dimensional gamut diagram obtained in the example!

[FIG. 3] FIG. 3 is an a * b * two-dimensional gamut diagram obtained in the example.

FIG. 4 is a spectral reflection curve of each color ink obtained in the examples.

FIG. 5 is a spectral reflection curve of each color ink obtained in the examples.

FIG. 6 is a graph showing the transparency of yellow ink used in Examples.

FIG. 7 is a graph showing opacity of yellow ink used in Examples. BEST MODE FOR CARRYING OUT THE INVENTION

[0020] The first invention is an offset printing method using yellow, red, indigo and black inks, wherein yellow, red and indigo inks are printed on newspaper Japan color standard paper of ISO standard (ISO 12647-2: 1998). In addition, the L * a * b * value of each color when the solid density was printed alone at the standard density value, and the two types of yellow, red, and indigo ink strength were also selected. In this case (hereinafter, two types of overprinting may be expressed as red ink X yellow ink, red X yellow, etc.), the L * a * b * values of each color are within the following ranges. And indigo ink.

'Yellow ink L *: 75 to 85, a *: 0 to 1, 10, b *: 60 to 70,

Red ink L water: 52-62, a water: 46-56, b water: 5-1-1,

Indigo ink L *: 52 ~ 62, a *:-20-20-30, b *:-24-24

'Red and yellow ink overprint (over yellow ink over red ink) L *: 50-60, a *

: 37-50, b *: 27-37,

'Overprinting of indigo and yellow ink (overprinting yellow ink on indigo ink) L *: 50-60, a *:-35-45, b *: 16-26,

'Overprinting of indigo and red ink (overprinting red ink on indigo ink) L *: 35 to 45, a *: 10 to 20, b water: 1 to 30 to 40. In the present invention, when ink is overprinted in order to evaluate the ink characteristics, the ink is printed in the order of black ink, indigo ink, red ink, and yellow ink. The order of ink when actually performing offset printing using the method of the present invention or the ink set of the present invention is not particularly limited, but is preferably black ink, indigo ink, red ink, yellow ink in this order. is there.

In the present invention, the “density value” means ISO standard Japanese color paper for newspaper (for example, Nippon Paper Industries Co., Ltd. newspaper paper (according to JCN paper, weighing 43 gZm ² , L *: 82, a *: -0. 4, b *: 4. 6)), yellow, red and indigo, and black ink if necessary, black ink, and Gretag Macbeth Spectro Eye (45Z0, D50, 2 ° field of view: Status T) Show the concentration value when measured with a densitometer.

[0023] The reference density values of the respective colors are yellow 0.85 to 0.95, red 0.88 to L00, indigo 0.84 to L00, and black 1.10 to 1.20. In the present invention, “printing as a reference density value” or “printing with a reference density value” or the like means solid printing in addition to performing solid printing so that the actually obtained printed matter becomes the reference density value. This includes the case where printing is performed under the printing conditions (ink amount, printing pressure, etc.) for obtaining a printed material having the reference density value.

The density value when actually performing offset printing using the method of the present invention or the ink set of the present invention is not limited to the reference density value. The concentration value can be set appropriately according to the application.

[0025] The color reproduction area can be expressed in the XYZ color system (CIE1931 color system), the X Y Z table.

10 10 10 color system (CIE1964 color system), L * a * b * color system (CIE1976 color system), Hunter Lab color system, Munsell color system, L * u * V * color system (CIE1976) Color system).

[0026] In the L * a * b * color system (JIS Z 8729), “brightness” is expressed by the value of L * as the degree of brightness that can be compared regardless of hue. The color becomes brighter as L * becomes larger, and the color becomes darker as L * becomes smaller. In addition, the “hue” that is different for each color is expressed as a * and b * values. a * indicates the color in the red (+) to green (-) direction, and b * indicates the color in the yellow (+) to blue (-) direction. In each direction, the color becomes brighter as the absolute value increases, and the color becomes duller as it approaches the absolute value. This color system allows a single color to be numerically expressed using the values of L *, a *, and b *.

In addition to “lightness” and “hue”, “saturation” is expressed by C as the degree of freshness. C Can be obtained by the following calculation formula.

[Number 1]

0 = ("*) ² + (see *) ²

Regarding C, the color becomes brighter as the value increases, and the color becomes duller as the value decreases.

[0028] All color reproduction regions that can be expressed in one printed matter (including color spaces other than printed matter) are called color rendering regions (gamut). The simplest way to represent a gamut is to use a solid white area (yellow, red, indigo) and a single solid color overprint (yellow x red, red) in a two-dimensional space with a * as the horizontal axis and b * vertical axis. X Indigo, Indigo X Yellow) There is a method of plotting the values of 6 colors (a * vs. b *) and expressing it as a hexagonal area connecting adjacent points. The larger the hexagonal area, the wider the color reproduction area.

[0029] Next, Japan Color is a standard color for printing established by the ISOZTC130 National Committee. In the Japan Color for Newspapers (hereinafter also referred to as JC N), the “JCN2002 chart” includes IS012642 SCID chart (928 colors), IS012647 patterns (80 colors), and important in newspaper printing. Show the colorimetric value (L * a * b * value) of the print color (skin color, gray, vivid color) as data! / As printing conditions for reproducing this JCN2002 chart, standard conditions of international standards IS 02864-2 and IS012647-3 for newspaper printing are used. Ink and printing paper are commonly used in Japan, and the color characteristics of standard paper are determined for newspaper ink and newspaper printing paper CFCN. ). Common CN standard ink (for example, “Vuentian Echo Yellow H, Red H, Indigo H, Black HS” manufactured by Toyo Ink Co., Ltd.) and JCN standard paper (JCN paper standard is 43gZm basis weight) ^{2, L *: 82, a} * 0. 4, b * 4. is 6, for example, Nippon paper Co., ultra-light paper (basis weight ^{43gZm 2, L *:. 80} , a * - 0. 1 , B * 4.3) The L * a * b * value of the yellow, red, indigo and single-color solid parts, and the C value calculated from it are yellow inks: L water: 77, a water: 4, b water: 58, C: 58, red ink: L water: 53, a water: 44, b water: 0, C: 44, indigo ink, L water: 58, a water: 23, b water: 26, C: about 35! Yes. The density values at this time are 0.82 for yellow ink, 0.86 for red ink, and 0.84 for indigo ink.

[0030] The Japan color standard ink for newspapers is a Japanese standard ink determined as follows. First, on behalf of the TC130 National Committee, the Printing Ink Industry Association conducted a color development test on 17 types of jars, pumps, and keyless inks of 6 ink manufacturers that belonged to them, as follows. Were measured and aggregated to determine the “JCN ink color characteristic value”. The ink that embodies this “JCN ink color characteristic value” was designated as “JCN standard ink”.

[0031] The Japan color standard paper for newspapers is a Japanese standard paper defined as follows. The color tone of the top 10 brands shipped excluding imported paper and 100% used paper is measured, and the average value is revised to take into account the increasing trend of used paper content in recent years. Decided. The paper that embodies this “JCN paper color characteristics” is called “JCN standard paper”. The color characteristic values for Newspaper Japan Color are L *: 81.1, a *: — 0.2, b *: 5.2, tolerance ∆Ε≤2.5 (reference value: density 0.23, whiteness : 53. 0).

In the present invention, JCN standard paper (for example, Nippon Paper Industries Co., Ltd.) is used as a paper on which ink is printed when evaluating ink characteristics such as density and L * a * b * values. Made of ultra-lightweight paper (basis weight 43g / m ² ) The paper used when actually performing offset printing using the method of the present invention or the ink set of the present invention is The paper is not limited to JCN standard paper, and any paper such as art paper, coated paper, matte coated paper, high-quality paper, etc. can be used, and newspaper paper is preferable.

[0033] In the above method, an ink set containing the following ink can be preferably used.

[0034] Inks constituting the ink set are usually colored components (pigments), synthetic resins, vegetable oils, and

Contains petroleum solvents. The ink may contain an auxiliary agent such as a vehicle component dissolved by heating and a friction-resistant agent together with a gelling agent such as aluminum stearate or aluminum chelate as necessary. The ink of the present invention can be produced by a conventionally known method.

[0035] The content of the coloring component is preferably 5 to 40% by weight based on the total weight of the ink. The content of the synthetic resin is preferably 10 to 40% by weight with respect to the total weight of the ink, and the content of the vegetable oil is preferably 10 to 80% by weight with respect to the total weight of the ink. It is preferable that the content of the petroleum-based solvent is 0 to 50% by weight based on the total weight of the ink. Further, when an auxiliary agent is used, the content of the auxiliary agent is preferably 1 to 10% by weight with respect to the total weight of the ink.

[0036] Yellow ink is 400 ηπ! The maximum reflectance if set to 100% in the wavelength region of ~ 700 nm, the reflectance force 1-20 ^_0/0 in the wavelength range of 400 nm to 480 nm, the reflectance in the wavelength region of 530Nm～700nm 90 to 100 % Is preferred. The reflectance in the wavelength region of 400 nm to 480 nm is more preferably 1 to: LO%, and further preferably 1 to 5%. The reflectance in the wavelength region of 530 nm to 700 nm is more preferably 95 to 100%, and even more preferably 98 to 100%. Or, if the maximum reflectance in the wavelength range of 400nm to 700nm is 100%, 400ηπ! The reflectance in the wavelength region of ˜500 nm is preferably 10% or more, and the reflectance in the wavelength region of 530 nm to 700 nm is preferably 90 to 100%.

[0037] The red ink has a maximum reflectance of 50% to 100% in the wavelength region of 400nm to 500nm and a wavelength of 500nm to 560nm, assuming that the maximum reflectance in the wavelength region of 400nm to 700nm is 100%. The reflectance of the region is 1 to 20%, and the reflectance of the wavelength region of 630 nm to 700 nm is preferably 90% to 100%. The maximum reflectance in the wavelength region of 400 nm to 500 nm is more preferably 1 to 10%, and further preferably 1 to 5%.

[0038] Indigo ink is 400ηπ! When the maximum reflectance in the wavelength region of ˜700 nm is 100%, the reflectance power in the wavelength region of 400 nm to 530 nm is 50˜: L00 ⁰ / _o , and the reflectance in the wavelength region of 600 nm to 700 nm is 1 It is preferably ˜30%. The reflectance in the wavelength region of 400 nm to 530 nm is more preferably 80 to 100%, and further preferably 90 to 100%.

[0039] The reflectance of the ink is Gretag Macbeth Spectro Eye (45Z〇, D50, 2 degree field of view,

(Status T, Paper Zero).

[0040] Yellow pigments used in yellow ink include disazo yellow compounds such as CI pigment yellow 12 and CI pigment yellow 13, but are not limited thereto. Absent. Two or more pigments can be used in combination. Density value 1. When black ink is printed in the range of density value 0.85--0.95 on black ink printed within the range of 10-1.20, L * value power is 31 or less It is more preferable that it is less than 31. If the L * value has a transparency that does not exceed 31, a good color reproduction area with little influence on the underprinting ink can be obtained when overprinting as a secondary or tertiary color. . The L * value is preferably 1 or more and 30 or less, more preferably 10 or more and 25 or less, and still more preferably 15 or more and 25 or less. Or, density value 1.10 ~: When ink is printed over black ink in the range of L 20 and yellow ink is overprinted in the range of density value 0.85 ~ 0.95, L * value power 31 or more Preferably there is. If the L * value has an opacity of 31 or more, the original color of the yellow ink will be hidden in the paper with poor smoothness and whiteness used for newspaper printing, hiding the color of the paper. And a wide color reproduction region can be obtained. If the L * value is less than 31, the original color developability of yellow ink may not be obtained due to the influence of the lower paper. The L * value is preferably 31 or more and 50 or less, more preferably 32 or more and 40 or less, and still more preferably 33 or more and 37 or less.

In the case of using a disazo yellow compound, it is also possible to use CI pigment yellow 83 as a complementary color.

[0041] The content of yellow pigment (when using a combination of pigments, the total content) is preferably 5 to 15% by weight based on the weight of the entire ink. Further, when CI pigment yellow 83 is used, the content thereof is preferably 0.5 to L0% by weight, more preferably 2 to the total weight of CI pigment yellow 12 and CI pigment yellow 13 5% by weight.

[0042] Examples of red pigments used in red ink include rhodamine dye metal lake compounds, such as rhodamine dye molybdenum metal lake compounds and rhodamine dye tandastene metal lake compounds. It is not a thing. Two or more pigments can be used in combination. Examples of rhodamine dyes include rhodamine B, rhodamine 3G, and rhodamine 6G. Specific examples of red pigments include CI Pigment Red 81, CI Pigment Violet 1, and CI Pigment Red 169.

[0043] The content of red pigment (when using a combination of pigments, the total content) It is preferable that it is 15 to 20 weight% with respect to the weight of this.

[0044] Examples of the indigo pigment used in indigo ink include, but are not limited to, copper phthalocyanine compounds such as CI Pigment Blue 15: 3 and CI Pigment Blue 15: 4. Two or more pigments can be used in combination. In addition, CI Pigment Green 7 can be used as a complementary color.

[0045] The copper phthalocyanine compound is a substance exhibiting a crystal polymorphism (homogeneous heterocrystal). Copper phthalocyanine compounds are classified into a, j8, ε, π, τ,,%, R, etc., depending on the crystal structure. Excellent in crystal stability and dispersibility | 8-type copper phthalocyanine is preferable, and fine | 8-type copper phthalocyanine having a specific surface area of 74 m ² / g or more is preferable. The specific surface area is preferably 74 to 80 m ² Zg, more preferably 74 to 78 m ² Zg, still more preferably 74 to 76 m ² Zg. In the present invention, the value calculated from the surface area according to the following formula is defined as the specific surface area. The surface area can be measured using a flow type specific surface area measuring device “Flow Soap II” manufactured by Shimadzu Corporation. Specific surface area (m ² Zg) = Surface area (m ² ) Z powder Mass (g)

[0046] The halogenated copper phthalocyanine compound in which the hydrogen atom on the benzene ring of the copper phthalocyanine molecule is substituted with a halogen compound is preferably 5 to 15% by weight, more preferably 8 to L based on the weight of the copper phthalocyanine compound. It is preferable to add 1% by weight. From the standpoint of expanding the green and purple color reproduction areas when printed with yellow and red inks that do not impair the color reproduction area of indigo ink, it is preferable to use a copper halide phthalocyanine compound.

[0047] The content of the indigo pigment (the total content when pigments are used in combination) is preferably 5 to 25% by weight based on the total weight of the ink, and 10 to 25% by weight. More preferably, it is 5 to 15% by weight. When CI pigment green 7 is used, the content thereof is preferably 5 to 15% by weight, more preferably 8 to 8%, based on the total weight of CI pigment blue 15: 3 and CI pigment blue 15: 4. : L 1% by weight. Alternatively, when CI pigment green 7 is used, its content is preferably relative to the total weight of the ink. . 5-2. 0 weight ^_0/0.

[0048] Examples of black pigments include carbon black, such as CI pigment black 7. . Two or more pigments can be used in combination. The ink pigment content (total content when pigments are used in combination) is preferably 10 to 35% by weight based on the total weight of the ink. More preferably, the content is 13 to 23% by weight.

[0049] Examples of the synthetic resin include rosin-modified phenol resin, petroleum resin, alkyd resin, rosin-modified alkyd resin, petroleum resin-modified alkyd resin, and rosin ester. Preferably, rosin-modified phenolic rosin is used. The rosin-modified phenol resin is not particularly limited, but the weight average molecular weight is preferably 10,000 to 400,000, more preferably 10,000 to 300,000, and more preferably 70,000 to 300,000. Further preferred. If the molecular weight is less than 10,000, the viscoelasticity of the ink decreases, and if it exceeds 400,000, the fluidity of the ink tends to be insufficient.

[0050] Examples of vegetable oils include palm kernel oil, coconut oil, cottonseed oil, peanut oil, palm oil, corn oil, olive oil, linseed oil, corn oil, soybean oil, safflower oil, and tung oil. And oxygen-blown polymerization oil. In the present invention, these vegetable oils may be used alone or in combination of two or more.

[0051] As the petroleum solvent, a petroleum solvent having an aromatic hydrocarbon content of 1% or less is preferred. Also, it is preferable that the Arin point is 75 to 95 ° C, more preferably 80 to 95 ° C. Furthermore, the boiling point is preferably 260 ° C to 350 ° C, more preferably 280 to 350 ° C. If the Ferrin point is less than 75%, the ability to dissolve the resin is too high, so the ink setting tends to be slow, and if it exceeds 95 ° C, the resin dissolves. Due to the poor nature, gloss and inking tend to be poor. When the boiling point is less than 260 ° C, the evaporation of the ink solvent increases on the printing press, and the transferability of the ink to the roller, blanket, plate, etc. tends to deteriorate due to the deterioration of the fluidity of the ink. is there. When the temperature exceeds 350 ° C, the drying of the heat-set type ink tends to be inferior.

[0052] Further, the ink contains a gelling agent, a pigment dispersant, a metal dryer, a drying inhibitor, an antioxidant, an antifriction agent, an anti-set-off agent, a nonionic surfactant, if necessary. Additives such as polyvalent alcohol can be appropriately used.

[0053] By using the offset printing method or ink set provided by the present invention, Yellow, red, indigo, and black ink process It is possible to reproduce a wider color area than the color area that was reproduced by four-color printing. Further, in the present invention, since the fluorescent pigment is not used as a means for expanding the color reproduction region of the printed matter, a highly saturated printed matter that does not deteriorate over time such as fading of the printed matter without deteriorating printability is obtained. be able to.

Example

[0054] Next, the present invention will be described in more detail with reference to specific examples, but the scope of the present invention is not limited to these examples. In addition, the part of the following description represents a weight part and% represents weight%.

[0055] (Manufacture of rosin-modified phenolic rosin gel varnish A)

In a four-necked flask equipped with a condenser, thermometer, and stirrer, rosin-modified phenolic resin (Arakawa Chemical Industries, Ltd .: weight average molecular weight 150,000, acid value 20, softening point 160 ° C) 3 8. 5 parts, 30 parts of soybean oil and 30 parts of AF Solvent No. 5 (manufactured by Nippon Oil Corporation) were charged to obtain a mixture. The resulting mixture was heated to 180 ° C., stirred at the same temperature for 30 minutes, and then allowed to cool. Next, 1.0 part of ethylacetoacetate aluminum disoboxide (ALCH manufactured by Kawaken Fine Chemical Co., Ltd.) was added to the mixture as a gelling agent, and the mixture was stirred at 180 ° C for 30 minutes, and rosin-modified phenolic resin. Gel varnish A (hereinafter referred to as gel varnish A) was obtained.

[0056] Example of ink (yellow ink la)

In the formulation shown in Table 1, CI Pigment Yellow 1 2 (LIONOL YELLOW 1245—P) manufactured by Toyo Ink Manufacturing Co., Ltd. was gradually added under a temperature of 75 ° C in a kneader. To obtain a mixture. The mixture was kneaded for primary dehydration. Next, under a condition where the temperature is 100 ° C to 120 ° C and the degree of vacuum is 76mmHg, the secondary pressure is reduced so that the water content in the mixture is 0.5% by weight or less by evacuation for 1 hour. Dehydration was performed. After dehydration, the remaining gel varnish A, AF solvent No. 5 and soybean oil were added, kneaded and diluted, and the undispersed base ink was taken out from the kneader. Take out the undispersed base ink that has been taken out using a three roll with a roll temperature of 60 ° C, and knead until the dispersed particle size becomes 7.5 / zm or less with a dispersed particle measuring machine (grind meter). Ink la was obtained. Next, gel varnish A, soybean oil, compound (dispersion of hexametaline soda, etc.) and AF Solvent No. 5 were added to the base ink la in the formulation shown in Table 2 to obtain yellow ink la.

[0057] Ink Example (Red Ink 2a) In the same manner as yellow ink la, CI base red 2a was obtained using CI pigment red 81 (Fanarose RNN-P, manufactured by Fuji Kasei Co., Ltd.) according to the formulation shown in Table 1. Next, base ink 2a was mixed with gel varnish A, soybean oil, compound, and AF solvent No. 5 with the composition shown in Table 2 to obtain red ink 2a.

[0058] Example of ink (Indigo ink 3)

CI pigment blue 15: 3 (LIONO L BLUE FG 7330 manufactured by Toyo Ink Mfg. Co., Ltd.) was mixed with gel varnish A in the formulation shown in Table 2, and dispersed particles were measured using a dispersed particle system measuring machine (grind meter). The mixture was kneaded until the diameter was 7.5 m or less. Further, soybean oil, compound (dispersion of hexametaline soda, etc.) and AF Solvent No. 5 were added to the mixture to obtain indigo ink 3.

[0059] Example of ink (yellow ink lb)

CI Pigment Yellow 12 (LIONOL YELLOW 1245 P, manufactured by Toyo Ink Manufacturing Co., Ltd.) is replaced with CI Pigment Yellow 12 (LIONOL YELLOW 1 243—P, manufactured by Toyo Ink Manufacturing Co., Ltd.). A yellow ink lb was obtained.

[0060] Ink Example (Red Ink 2b)

Under a condition of 75 ° C. in a kneader, C. I. Pigment Red 169 (BASFtti¾Fanal Pink D4810) 36 parts was gradually added with gel varnish A 60 parts to obtain a mixture. The mixture was kneaded for primary dehydration. Next, secondary dehydration is performed so that the water content in the mixture is 0.5 wt% or less by evacuating for 1 hour under the conditions of a maker temperature of 100 ° C to 120 ° C and a degree of vacuum of 76 mmHg. went. After dehydration, 4 parts of the remaining gel varnish A and AF Solvent No. 5 were added, kneaded and diluted, and the undispersed base ink was taken out from the kneader. Take out the base ink using three rolls with a roll temperature of 60 ° C and knead it with a dispersed particle system measuring machine (grind meter) until the dispersed particle size is 7.5 / zm or less. Obtained. Next, 50 parts of base ink 2b, 20 parts of Genorevanis A, 8 parts of soybean oil, 20 parts of compound (dispersion of hexametaline soda, etc.) and 2 parts of AF Solvent No. 5 are added to the ink. 2b was obtained.

[0061] It should be noted that the method of the comparative example includes a general newspaper ink (Toyo Ink Mfg. Co., Ltd. "Vante Ancho Yellow H (CI Pigment Yellow 12), Red H (Kermin 6B), Indigo H (CI Pigme Blue 15: 3, black ink HS (CI pigment black 7)).

[0062] Printing evaluation test

About the ink of the said Example and the comparative example, the monochromatic solid printing and the solid overprint printing were performed on the following printing conditions. The black ink used was a general offset printing ink (black HS (C.I. Pigment Black 7)).

[0063] Printing conditions

Printing machine: LITHOPIA BT2-800 NEO (Mitsubishi Heavy Industries, Ltd.)

Printing order: ink → indigo → red → yellow

Paper: Newspaper renewal: Ultra-light paper (Weighing 43 g / m ² ) (Nippon Paper Industries Co., Ltd.) (Colorimetric values: L *: 82, a water: 0.4, b water: 4.6)

Dampening solution: NEWSKING ALKY (Toyo Ink Manufacturing Co., Ltd.) 0.5% tap water printing speed: 100,000 copies at Z

[0064] Printed matter evaluation method

Density: Gretag Macbeth Spectro Eye (45Z0, D50, 2 ° field of view: Status T) The density value of the solid color (yellow, red, indigo, black) of the printed matter was measured. Yellow 0.85 ~ 0.95, Red 0.88 ~: L 00, Indigo 0.84 ~: L 00, Black 1.10 ~: L 20

Colorimetry: Gretag Macbeth Spectro Eye (45Z〇, D50, 2 ° Field of view: Status T) Solid color solid part (yellow, red, indigo) and solid solid color overprinted part (yellow x red, red x indigo) , X ¾) »L *, a *, b * values were measured.

C value was calculated by the following formula: a * and b * force.

[Equation 2]

Spectral reflectance: The spectral reflectance of the ink was measured with Gretag Macbeth Spectro Eye (45 ° θ, D50, 2 ° field of view: Status T, Paper zero).

[0065] The results are shown in Tables 3-5. Compared with the comparative example, the printed matter having a larger C value in the example had higher saturation. Table 3 shows the results using yellow ink la, red ink 2a, and indigo ink 3. , Yellow ink lb, red ink 2a, and indigo ink 3, and Table 5 shows the results using yellow ink la, red ink 2b, and indigo ink 3.

[0066] In addition, as a result of comparison in a two-dimensional gamut in which a * and b * values are plotted in a two-dimensional space in which a * is the horizontal axis and b * is the vertical axis, The color reproduction area was wider (Figs. 2 and 3). Figure 2 shows the results using yellow ink la, red ink 2, and indigo ink 3, and Figure 3 shows the results using yellow ink lb, red ink 2, and indigo ink 3.

[0067] Further, the obtained spectral reflectance curves are shown in Figs. Compared to the conventional ink of the comparative example, the ink of the example is closer to the ideal spectral reflectance curve, and the absorption in the wavelength region that must be completely reflected is less. Therefore, the turbidity component of the ink decreased, and when these inks were used, the color reproduction range expanded (Figures 2 and 3). FIG. 4 shows the results using yellow ink la, red ink 2a, and indigo ink 3, and FIG. 5 shows the results using yellow ink lb, red ink 2a, and indigo ink 3.

[0068] The transparency of the yellow ink was evaluated by the following test method.

Density value 1. On black ink solidly printed within the range of 10 to 1.20, the density of 0.80 to: L10, the yellow ink la or lb was printed with a solid color, and L * was measured. . The results are shown in FIGS. The yellow ink la had an excellent transparency that caused L * to not exceed 31 over the entire measured density range, and had little effect on the underprinted ink. (The smaller the L * value, the darker the color of L *. The higher the value, the whiter the color).

[0069] On the other hand, the yellow ink of the comparative example inhibited the blackness of the black ink of the underprint because the yellow ink of the overprint having a high L * was opaque.

[0070] Further, the yellow ink lb had L * of 31 or more in the entire measured density range. The yellow ink lb conceals the underlying black ink, and the original color developability of the yellow ink appears and the color rendering is expanded (the smaller the L * value, the blacker the color, the larger the L * value, the more the color white). Fig. 6 shows the results using yellow ink 1a, and Fig. 7 shows the results using yellow ink lb.

[0071] [Table 1] table 1

[0072] [Table 2]

Table 2

[0073] [Table 3] Table 3 degrees ab C Example Yellow ink 1 a 0.89 78.2 One 5.2 63.0 63.2 Red ink 2a 0.93 54.9 49.9 -9.4 50.8 Indigo ink 3 0.90 56.4 -24.7 -29.2 38.2 Yellow ink 1 a X Red Ink 2a 1 54.1 41.6 29.1 50.8 Red ink 2a X regular ink 3 1 39.8 16.0-32.7 36.4 Indigo ink 3 X Yellow ink 1a ― 53.9 -38.4 20.4 43.5 Comparative example Yellow ink 0.88 78.1 -5.0 61.9 62.1 Red ink 0.89 52.7 43.5 -4.0 43.7 Indigo ink 0.86 58.4 -24.2 -25.9 35.5 Yellow ink X Crimson ink ― 51.1 39.3 23.6 45.8 Crimson ink X Adjustable ink 1 41.5 6.2 -24.0 24.8 Indigo ink X Yellow ink 1 54.9 -35.5 21.1 41.3 [0074] [Table 4] Table 4

[0075] [Table 5]

Table 5

辰 St and ab C Example Yellow ink la 0.89 78.2 -5.1 63.0 63.2 Red ink 2b 0.90 54.6 49.8 -9.1 50.6 Blue ink 3 0.90 56.2 -24.5 -29.3 38.2 Yellow ink 1a X red ink 2b ― 54.0 41.4 29.0 50.5 Red ink 2b Indigo ink 3 —— 39.6 15.8 -32.4 36.0 Indigo ink 3 X Yellow ink 1a —— 54.0 -38.4 20.1 43.3 Comparative example Yellow ink 0.88 78.1 -4.9 61.4 61.6 Red ink 0.89 52.5 43.4 -4.0 43.6 Indigo ink 0.86 58.3 One 24.0- 25.8 35.2 Yellow ink X Red ink ― 51.0 39.2 23.5 45.7 Red ink X Indigo ink ― 41.6 6.0-24.0 24.7 Blue ink X Yellow ink ― 54.7 -35.2 21.0 41.0

Claims

The scope of the claims

[1] Yellow, Crimson, Indigo and Black Ink Strength This is an offset printing method using selected ink. Yellow, Crimson and Indigo inks are solidly printed on ISO standard newspaper Japan color standard paper at a standard density value. L * a * b * value of each color when printed, and L * a * b * of each color when two colors selected from yellow, red, and indigo ink are printed with a solid density at the standard density value Value offset printing method characterized by using yellow, red and indigo inks in the following range.

Here, the standard concentration values are 0.85-0.95 yellow, 0.88-1.00 red, 0.84-1.00 indigo,

L water a water b water level ί,

Yellow ink L water: 75 to 85, a water: 0 to 1, 10, b water: 60 to 70,

Red ink L water: 52 to 62, a water: 46 to 56, b water: -5 to 1-15,

Indigo ink L *: 52 ~ 62, a *:-20 ~ 30, b *:-24 ~ 34

Red and yellow ink overprint L *: 50 to 60, a *: 37 to 50, b *: 27 to 37, Indigo and yellow ink overprint L *: 50 to 60, a *: 35 to 1 45 B *: 16 to 26, indigo and red ink overprint L *: 35 to 45, a *: 10 to 20, b *: —30 to 1-40.

[2] Yellow, red, indigo, and black ink strength The offset ink printing method using the selected ink, wherein the following yellow, red, and indigo inks are used.

400η when the maximum reflectance in the wavelength region of 400nm to 700nm is 100% Indigo ink having a reflectance of 50 to 100% in the wavelength region of m to 530 nm and a reflectance of 1 to 30% in the wavelength region of 600 to 700 nm.

[3] An ink set for offset printing comprising the following yellow, red, and indigo inks, and black ink.

Crimson ink containing 15 to 20% by weight of C. I. Pigment Red 81, C. I Pigment Violet 1 or C. I. Pigment Red 169 as a metal lake compound of a rhodamine dye.

[4] An ink set for offset printing comprising the following yellow, red and indigo inks, and black ink.

As a disazo yellow compound, CI Pigment Yellow 12 or C.I Pigment Yellow 13 is contained in an amount of 5 to 15% by weight based on the total weight of the ink. Yellow ink with a L * value of 31 or more when solidly printed with a density of 0.85-0.95.

[5] An offset printing ink set comprising the following yellow and red inks, and indigo and black inks. When the maximum reflectance in the wavelength region of 400 nm to 700 nm is 100%, the reflectance in the wavelength region of 400 ηm to 480 nm is 1 to 20%, and the reflectance in the wavelength region of 530 nm to 700 nm is 90 to 100%. Is yellow ink.

[6] The ink set for offset printing according to claim 5, wherein the following indigo ink is provided.

When the maximum reflectance in the wavelength region of 400 nm to 700 nm is 100%, the reflectance in the wavelength region of 400 ηm to 530 nm is 50 to 100%, and the reflectance in the wavelength region of 600 nm to 700 nm is 1 to 30. Indigo ink that is%.

[7] An ink set for offset printing, comprising the following yellow and red inks, and indigo and black inks.

When the maximum reflectance in the wavelength region of 400 nm to 700 nm is 100%, the maximum reflectance in the wavelength region of 400 ηm to 500 nm is 50% to 100%, and the reflectance in the wavelength region of 500 nm to 560 nm is 1 to 20%, 90% reflectivity in the wavelength range from 630nm to 700nm

Red ink that is 100% to 100%.

[8] The ink set for offset printing according to claim 7, wherein the following indigo ink is provided.

9. The offset printing method according to claim 1 or 2, wherein the ink is a permeation drying type printing ink.

[10] A printed matter printed using the offset printing method according to claim 1 or 2.

[11] An ink set for use in the offset printing method according to claim 1 or 2.

[12] The offset printing according to claim 3-8, wherein the ink is a osmotic drying type printing ink. Ink set.

A printed matter printed using the offset printing ink set according to claim 3-8.

[14] A printing method using the offset printing ink set according to any one of claims 3 to 8,