JP2009013288A - Ink composition for infiltration drying type offset printing and printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing method reproducing a color region wider than a color reproduction region of RGB expressed by conventional yellow, red, blue and black process four-color printing. <P>SOLUTION: In infiltration drying type offset printing using two or three of yellow, red and blue ink and a black ink, the yellow ink is one for infiltration drying type offset printing containing 5-15% of a disazo yellow compound, the red ink is one for infiltration drying type offset printing containing 15-20% of a metal lake compound of a rhodamine dye, and the blue ink is one for infiltration drying type offset printing containing 0.7-2.0% of a phthalocyanine compound which are used in combination. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a printing method of offset printing ink comprising four process colors of yellow, red, indigo, and black, and relates to a printing method using an ink system that is excellent in color reproducibility with four colors and high saturation.

  In addition, on the newspaper paper with high whiteness (high white newspaper), the above-described penetrating dry type offset printing ink comprising four process colors of yellow, red, indigo and black, which can reproduce the high-saturation color, is used. The present invention relates to a printing method for penetrating dry type offset printing ink, which is excellent in color reproduction with high saturation, which cannot be achieved by a conventional penetrating dry type offset printing ink printing method.

  The IT revolution that began in the 1990s has led the environment surrounding the printing site to the direction of digitalization. By this digitization, workflow of conventional printing methods (photographing, positive, scanning, data, design, EPS)・ Imposition, film, printing plate, printing) was a multi-stage process, but it has succeeded in dramatically shortening the process with digital camera shooting, DTP, CTP, and printing. As a result, “RGB” conversion of the submitted data is being standardized, and the current situation is that the data to be handled is shifting to a wider color reproduction region.

  However, in lithographic offset printing consisting of four process colors (CMYK) of yellow, red, indigo and black, which are currently mainstream, the color reproduction area is necessarily narrower than that of RGB because of the hue due to subtractive color mixing. The difference in color reproducibility between digital data and printed matter became a problem.

  In particular, in paper printing (newspaper printing) using penetrating dry ink, there are problems of whiteness and smoothness of paper, and the color reproduction area is narrower than that for coated paper, and sample from digital data. The difference in color reproducibility with the printed matter becomes a serious problem.

  In newspaper printing using penetrating dry ink, there is a growing demand for more colors in recent years, and there is a tendency for color pages on newspapers to increase. Differentiation of the paper surface by quality improvement is strongly desired.

  As means for solving this, in Patent Document 1, a printing method using an ink set of 5 to 7 colors is established as a high-saturation printing system. As a printing method using an ink set having each specified hue, process 4 colors are used. 6 colors (hexachrome printing) with orange and green added to 7 colors and 7 colors (high fidelity printing) with orange, green and purple added to 4 process colors have been established. In addition, as represented by hexachrome ink, as a means of expanding the color reproduction area, a technique such as adding a fluorescent pigment to a part of the color is used. However, deterioration of printability (transfer defect, gloss reduction, etc.) There are also disadvantages such as fading of printed matter due to insufficient light resistance. Furthermore, the number of ink colors used is 6 or 7, and an expensive multicolor printing machine with 6 or more printing cylinders is required. It is an indispensable condition, and it is limited to using this system due to huge capital investment and complicated color management to start a new one.

  Patent Document 2 discloses a printing method using a four-color ink set as a high-saturation printing system, but there is no description of a method for producing each color ink, and there is a great doubt as a patent.

  Furthermore, in newspaper printing, most printers for process four colors are mostly used, and multi-color machines of five or more colors have not been introduced into the market as general-purpose products. It is particularly difficult to increase the color saturation of a paper surface by a multicolor printing method of a cylinder or higher. Therefore, it is important to develop a high color rendering ink and establish a printing method for obtaining high color saturation including printing paper.

Conventionally, in newspaper printing, attempts have been made to increase the saturation by increasing the ink volume and increasing the density on the paper surface, but increasing the ink volume increases the saturation of the paper surface, Ink setting property is delayed, causing set-off stains, guide stains, and the like. In addition, attempts have been made to increase the pigment concentration and increase the paper surface density without changing the ink volume, but this has led to deterioration in printing suitability such as emulsification suitability, and is still osmotic dried by these methods. Printing methods for ink for offset printing are not widely used.
JP 2001-260516 A Special table 2007-500091 gazette

  The present invention has been made in order to solve such problems in the prior art, and the problem is that an RGB color reproduction region using a four-color printing machine that has been widely used in the past. The present invention provides a penetrating dry type offset printing ink comprising four process colors of yellow, red, indigo and black, and a printing method thereof.

  That is, the present invention relates to an infiltration dry type offset printing ink composition comprising four process colors of yellow, red, indigo and black, and yellow, red, and indigo are yellow inks having a disazo yellow compound as a pigment component. And an infiltration dry offset printing ink composition comprising a combination of a red ink containing a rhodamine dye metal lake compound as a pigment component and an indigo ink containing a phthalocyanine compound as a pigment component.

  Also, on high-white newspaper with high whiteness, printing at a specified concentration using penetrating dry offset printing ink consisting of four process colors of yellow, red, indigo and black, which can reproduce the high-saturation color described above. Thus, the present invention relates to a printing method of penetrating dry type offset printing ink excellent in high chroma color reproducibility which cannot be achieved by a conventional printing method.

  That is, the present invention relates to C.I. I. Pigment yellow 12 or C.I. I. Pigment Yellow 13 is contained in an amount of 5 to 15%, and the L * value is 31 or more when printed over black ink having a density value of 1.10 to 1.20 in the range of 0.85 to 0.95. The present invention relates to a penetrating dry type yellow ink for offset printing.

  The present invention also relates to a permeation dry offset printing red ink containing 15 to 20% of C.I. Pigment Red 81, C.I. Pigment Red 169 or C.I. Pigment Violet 1 as a metal lake compound of a rhodamine dye.

  The present invention also relates to an osmotic dry offset printing containing 10 to 25% CI pigment blue 15: 3 or CI pigment blue 15: 4 and 0.7 to 2.0% CI pigment green 7 as a phthalocyanine compound. This is related to indigo ink.

  By using the printing method of penetrating dry type offset printing ink provided by the present invention, a wider color area than the RGB color reproduction area expressed by the conventional four-color printing of yellow, red, indigo and black ink processes can be obtained. It becomes possible to reproduce. Further, in the present invention, since a fluorescent pigment is not used as a means for improving the color reproduction region of the printed material, a highly saturated printed material can be obtained without deteriorating printability, fading with time of the printed material, and the like.

  Furthermore, by using high-white newsprint paper, which has a much higher whiteness than the ISO standard Japanese color paper for newspapers, absorption in the visible light region due to the additional paper, especially absorption in paper with a wavelength range of 380 to 600 nm. In particular, the reflectance of yellow, green (indigo x yellow), indigo, blue-purple (indigo x red) areas can be improved, and the color reproducibility of yellow, green, indigo, and bluish purple can be greatly improved. become.

  Next, the present invention will be described more specifically with reference to preferred embodiments.

The present invention comprises a pigment, a vehicle component obtained by heating and dissolving a synthetic resin, a vegetable oil, and a petroleum solvent together with a gelling agent such as aluminum stearate or aluminum chelate as necessary, and an auxiliary agent such as a friction-resistant agent. A high-white newsprint with a whiteness of 60 to 85%, such as a high-white newsprint manufactured by Oji Paper Co., Ltd. (weighing 52 g / m ² , L *: 92, a *: 0.2, b *: 0.8), yellow, red, and indigo colors Gretag Macbeth Spectro Eye (45/0, D50, 2 degrees field of view: Status T) densitometer When the density value when measured in is in the range of 0.90 to 1.00 for yellow, 0.90 to 1.02 for red, and 0.90 to 1.05 for indigo, single color and each single color The chromaticity (JIS Z 8729) according to the L * a * b * color system for printing
Yellow ink, L *: 82 to 92, a *: -10 to 0, b *: 75 to 85
Red ink, L *: 55-65, a *: 56-67, b *: -24 to -12
Indigo ink, L *: 55 to 65, a *: −35 to −25, b *: −50 to −35
The chromaticity of overprinting of the above two ink colors is (JIS Z 8729),
By overprinting red ink and yellow ink,
L *: 52-62, a *: 47-57, b *: 30-40
By overprinting indigo ink x yellow ink,
L *: 50 to 60, a *: −55 to −40, b *: 20 to 30
By overprinting indigo ink x red ink,
L *: 37 to 47, a *: 12 to 27, b *: −47 to −37
It is characterized by being in the range of

  As a method for expressing the color reproduction area, an XYZ color system (CIE1931 color system), an X10Y10Z10 color system (CIE1964 color system), an L * a * b * color system (CIE1976), a Hunter Lab color system, Munsell color system, L * u * v * color system (CIE1976), and the like.

In the L * a * b * color system, “brightness” is expressed by L * as the degree of brightness that can be compared regardless of hue, and indicates that the color becomes brighter as L * increases and becomes darker as it decreases. . In addition, “hue” that differs depending on each color is indicated by a * and b * values, a * indicates a red (+) to green (−) direction, and b * indicates a yellow (+) to blue (−) direction, In each direction, the color becomes brighter as the absolute value increases, and the color becomes dull as it approaches 0. This makes it possible to digitize one color using L *, a *, and b *. In addition to “lightness” and “hue”, there is “saturation (C)” as a method for digitizing the degree of vividness, which can be obtained by the following calculation formula.

Ｃに関しても同様に、絶対値が大きくなるに従って色鮮やかになり、値が小さくなるにつれてくすんだ色になることを示している。

Similarly, C shows that the color becomes brighter as the absolute value increases, and the color becomes dull as the value decreases.

  All color reproduction areas that can be represented by a single printed matter (including color spaces other than printed matter) are called color rendering regions (gamut). The simplest way to represent gamut is as follows: a * is the horizontal axis, b * vertical axis In the two-dimensional space, the solid color part (yellow, red, indigo) and the solid color overprinting part (yellow x red, red x indigo, indigo x yellow) total of 6 colors a * vs b *, It can be expressed by the plotted hexagonal area. The larger the gamut area, the wider the color reproduction area.

  The high white newsprint used in the present invention is preferably a high white newsprint with a whiteness of 60 to 85%, more preferably 63 to 85%. If it is 60% or less, the whiteness of the paper that is currently used generally is about 53%, so a large difference cannot be obtained, and if it is 85% or more, the whiteness is increased. This makes it impossible to maintain the ratio of old waste paper, which increases the cost of printing paper and further imposes a burden on the environment. The high white newsprint used in the present invention may be acid paper or neutral paper as long as the whiteness is in the range of 60 to 85%.

  Generally, in the case of printing with a penetrating dry ink (especially for newspaper printing), about 5 to 15% of the absorption of paper is potentially caused over a portion of the visible light region of 380 to 600 nm. ing. As a result, the reflectance in this wavelength region decreases and the yellowish hue of the paper becomes stronger, so the effect of coloration of the blue component by the copper halide phthalocyanine compound, particularly from the purple region of the indigo and red layer, to the indigo and yellow colors. The coloring effect is hindered over the overlapping green region. However, by printing on high-white newsprint with high whiteness, it becomes possible to increase the reflectance in the visible light region from 380 to 600 nm by 5 to 15%, so the color reproduction region of indigo ink is reduced. In addition, the green and purple color reproduction areas overprinted with yellow ink and red ink can be expanded more than when using a conventional reprint paper. Since the effect of improving the reflectance in the visible light region of 380 to 600 nm becomes higher as the paper with higher whiteness is printed, it is preferable to use high white paper with higher whiteness.

  The yellow pigment used in the present invention is a disazo yellow compound such as CI Pigment Yellow 12, CI Pigment Yellow 13, and the like on a black ink printed within a density value range of 1.10 to 1.20. Furthermore, if the density of the yellow ink is overprinted in the range of 0.85 to 0.91, if the L * value has an opacity of 31 or more, the smoothness used in newspaper printing is inferior and white. In the case of inferior paper, the original coloring property of the yellow ink is obtained by hiding the lower paper, so that a good color reproduction region can be obtained. If the L * value is less than 31, the original color developability of yellow ink cannot be obtained due to the influence of the lower paper.

  Further, it is also possible to use C.I. Pigment Yellow 83 as a complementary color by adding 0.5 to 10%, preferably 2 to 5% of the above yellow pigment.

  Examples of red pigments include, but are not limited to, rhodamine-based dyes such as rhodamine B, rhodamine 3G, rhodamine 6G, molybdenum, tungsten metal lake compounds such as C.I. Pigment Red 81 and C.I. Pigment Violet 1. These red pigments may be used alone or in combination of two or more. These red pigments should be contained in an amount of 10 to 30%, more preferably 10 to 20%, based on the total ink.

  Examples of indigo pigments include phthalocyanine compounds such as C.I. Pigment Blue 15: 3 and C.I. Pigment Blue 15: 4. Further, C.I. Pigment Green 7 may be used as a complementary color by adding 5 to 15%, preferably 8 to 11% of the indigo pigment.

The copper phthalocyanine compound, which is a cyan pigment used in the present invention, is a substance exhibiting a crystal polymorphism (homogeneous heterocrystal), and α, β, γ, ε, π, τ, ρ, χ depending on the crystal structure. However, it is preferable to use a β-type having excellent crystal stability and dispersibility, and further a fine β-type copper phthalocyanine having a specific surface area of 74 m ² / g or more. preferable.

  Examples of the black pigment include carbon black such as C.I. Pigment Black 7.

  As the synthetic resin used in the present invention, rosin-modified phenol resin, petroleum resin, alkyd resin, rosin-modified alkyd resin, petroleum resin-modified alkyd resin, rosin ester and the like can be considered. Preferably, a rosin modified phenolic resin is used. The rosin-modified phenol resin is not particularly limited, but it is preferable to use a resin having a weight average molecular weight of 10,000 to 300,000. When the molecular weight is 10,000 or less, the viscoelasticity of the ink is lowered, and when it is 400,000 or more, the fluidity as the ink becomes insufficient.

  Examples of vegetable oils include those derived from vegetable oils such as palm kernel oil, palm oil, cottonseed oil, peanut oil, palm oil, corn oil, olive oil, linseed oil, corn oil, soybean oil, safflower oil, and tung oil, Those thermal polymerized oils and oxygen-blown polymerized oils can also be used. Moreover, in this invention, these vegetable oils may be used independently and can also be used in combination of 2 or more type.

  The petroleum solvent used in the ink has an aromatic hydrocarbon content of 1% or less, an aniline point of 75 to 95 ° C, preferably 80 to 95 ° C, and a boiling point of 260 to 350 ° C, preferably 280 to 350. It is a petroleum solvent in the range of ° C. If the aniline point is less than 75%, the ability to dissolve the resin is too high, which is not preferable because the ink setting property is slow, and if it exceeds 95 ° C., the resin solubility is poor, so Meat etc. are bad and not preferable. When the boiling point is less than 260 ° C., the evaporation of the ink solvent on the printing press increases, and the transferability of the ink to a roller, a blanket, a plate, or the like deteriorates due to the deterioration of the fluidity of the ink. On the other hand, when the temperature exceeds 350 ° C., the evaporation of the solvent that has penetrated into the paper is slowed down, resulting in deterioration of the penetration property.

  Furthermore, the offset ink composition of the present invention includes a gelling agent, a pigment dispersant, a metal dryer, a drying inhibitor, an antioxidant, an antifriction agent, an anti-set-off agent, and a nonionic surface active as required. Additives such as agents and polyhydric alcohols can be used as appropriate.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, the scope of the present invention is not limited to these description Example. In addition, the part of the following description represents a weight part and% represents weight%.

(Production of rosin-modified phenolic resin gel varnish A for offset)
38.5 parts of rosin modified phenolic resin (Arakawa Chemical Industries, Ltd .: weight average molecular weight 150,000, acid value 20, softening point 160 ° C.) in a four-necked flask equipped with a condenser, thermometer and stirrer, soybean oil 30 parts, 30 parts of AF Solvent No. 5 (manufactured by Nippon Oil Co., Ltd.) were charged, heated to 180 ° C., stirred at the same temperature for 30 minutes, allowed to cool, and ethyl acetoacetate aluminum as a gelling agent 1.0 part of diisopropoxide (ALCH manufactured by Kawaken Fine Chemical Co., Ltd.) was added and stirred at 180 ° C. for 30 minutes to obtain a rosin-modified phenol resin gel varnish A for offset (hereinafter referred to as gel varnish A).

[Ink Example] (Yellow ink)
In the formulation shown in Table 1, C.I. I. Pigment Yellow 12 (LIONOL YELLOW 1243-P manufactured by Toyo Ink Manufacturing Co., Ltd.) was subjected to primary dehydration by gradually adding and kneading gel varnish A in a kneader at a temperature of 75 ° C. Next, vacuum dehydration was performed for 1 hour under conditions of a kneader temperature of 100 ° C. to 120 ° C. and a degree of vacuum of 76 mmHg, and secondary dehydration was performed so that the water content in the base ink was 0.5% or less. 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. The extracted base ink was kneaded using a three roll with a roll temperature of 60 ° C. with a dispersed particle measuring machine (grind meter) to 7.5 μm or less to obtain yellow base ink 1. Next, gel ink varnish A, soybean oil, compound and AF solvent No. 5 were added to the base ink 1 according to the formulation shown in Table 2 to obtain yellow ink 1.

[Ink Example] (Red ink)
As with the yellow ink, C.I. I. A red base ink 2 was obtained using Pigment Red 81 (Funal Rose RNN-P manufactured by Fuji Kasei Co., Ltd.). Subsequently, the gel ink varnish A, soybean oil, the compound, and AF solvent No. 5 were added to the base ink 2 according to the formulation shown in Table 2 to obtain a red ink 2.

[Ink Example] (Indigo ink)
In the formulation of Table 2, C.I. I. Pigment Blue 15: 3 (LIONOL BLUE FG 7330 manufactured by Toyo Ink Mfg. Co., Ltd.) was mixed with varnish, and after milling with a dispersed particle measuring machine (grind meter) to 7.5 microns or less, soybean oil, Compound and AF Solvent No. 5 were added to obtain indigo ink 3.

The transparency of the yellow ink was evaluated by the following test method.
Overprinted with black ink density in the range of 0.80 to 1.10 on the black ink printed on the newspaper reprint surface within the density value range of 1.10 to 1.20, and measured the L * value. did. The results are shown in Table 4.

  In the yellow ink of the example, L * is always 31 or more in the measured density range, and the underlying black ink is concealed, and the original color developability of the yellow ink comes out and the color rendering is widened (L * is smaller as the value is smaller). Black indicates that the larger it is, the whiter it becomes)

  On the other hand, the comparative ink has a low L * and is affected by the black ink of the base, resulting in a narrow color rendering.

(Print evaluation test)
About the ink of the said Example and a comparative example, under the following printing conditions, each solid density value of yellow, red, and indigo is yellow: 0.90-1.00, red: 0.90-1.02, indigo: Printing was performed within the range of 0.90 to 1.05, and the printed matter was evaluated. The ink used was a general offset newspaper printing ink, and was printed within a density range of 1.12 to 1.20.

(Printing conditions) (Example)
Printing machine: LITHOPIA BT2-800 NEO (Mitsubishi Heavy Industries, Ltd.)
: Printing order: Ink->Indigo->Red-> Yellow Paper: High white newspaper: Medium quality paper (weighing 52 g / m ² ) (Oji Paper Co., Ltd.)
(Colorimetric value: L *: 92, a *: 0.2, b *: 0.8)
Dampening water: NEWSKING ALKY (Toyo Ink Manufacturing Co., Ltd.) 0.5% tap water solution Printing speed: 100,000 parts / hour

(Printing conditions) (Comparative example)
Printing machine: LITHOPIA BT2-800 NEO (Mitsubishi Heavy Industries, Ltd.)
: Printing order: Ink->Indigo->Red-> Yellow Paper: Newspaper for newspaper: Ultralight paper (weighing 43 g / m ² ) (Nippon Paper Industries Co., Ltd.)
(Colorimetric value: L *: 82, a *: -0.4, b *: 4.6)
Dampening water: NEWSKING ALKY (Toyo Ink Manufacturing Co., Ltd.) 0.5% tap water aqueous solution Printing speed: 100,000 parts / hour The ink used as a comparative example was a general osmotic drying offset printing ink.

(Printed material measurement conditions)
Density: Measure the density value of the solid part (yellow, red, indigo, black) of the printed matter with Gretag Macbeth Spectro Eye (45/0, D50, 2 degree field of view: Status T).
Color measurement: Gretag Macbeth Spectro Eye (45/0, D50, 2 degree field of view: Status T) Single color solid part (yellow, red, indigo) of printed matter and single color solid overprinted part (yellow x red, red) × L *, a *, b * values of indigo, indigo × yellow).

The C value was determined from the following formula using a * and b *.

  The results are shown in Table 3. Compared to the comparative example, the C value of the example is large, and the chroma of the printed matter is high. In addition, as a result of plotting each a * and b * value in a two-dimensional space with a * as the horizontal axis and b * vertical axis and comparing them with a two-dimensional gamut, it can be seen that the color reproduction region of the embodiment is wide. (Table 5).

Claims (3)

In penetrating dry offset printing using any two or three of yellow ink, red ink, and indigo ink, and black ink, the three colors of yellow ink, red ink, and indigo ink are combinations of the following pigment components: Osmotic drying type offset printing ink.
As a disazo yellow compound, C.I. I. Pigment yellow 12 or C.I. I. Pigment Yellow 13 is contained in an amount of 5 to 15%, and the L * value is 31 or more when printed over black ink having a density value of 1.10 to 1.20 in the range of 0.85 to 0.95. A yellow ink for penetrating dry offset printing.
A permeation dry offset printing red ink containing 15 to 20% of CI Pigment Red 81, CI Pigment Red 169 or CI Pigment Violet 1 as a metal lake compound of a rhodamine dye.
An infiltration dry offset printing cyan ink containing 10 to 25% CI pigment blue 15: 3 or CI pigment blue 15: 4 and 0.7 to 2.0% CI pigment green 7 as a phthalocyanine compound. Using any two or three of the yellow ink, red ink, and indigo ink according to claim 1 and lined ink, yellow ink, red ink on high white newsprint with a whiteness of 60 to 85%. Ink and indigo ink density values are within the range of 0.90 to 1.00 for yellow ink, 0.90 to 1.02 for red ink, and 0.90 to 1.05 for indigo ink. Or when printing by superposition, the chromaticity (JIS Z 8729) by the L * a * b * color system is
Yellow ink, L *: 82 to 92, a *: -10 to 0, b *: 75 to 85
Red ink, L *: 55-65, a *: 56-67, b *: -24 to -12
Indigo ink, L *: 55 to 65, a *: −35 to −25, b *: −50 to −35
The chromaticity of overprinting of the above two ink colors is (JIS Z 8729),
By overprinting red ink and yellow ink,
L *: 52-62, a *: 47-57, b *: 30-40
By overprinting indigo ink x yellow ink,
L *: 50 to 60, a *: −55 to −40, b *: 20 to 30
By overprinting indigo ink x red ink,
L *: 37 to 47, a *: 12 to 27, b *: −47 to −37
A method for printing a penetrating dry type offset printing ink excellent in color reproduction with high saturation, characterized in that it falls within the range of two of yellow ink, red ink and indigo ink according to claim 1 and black Osmotic dry offset printing that can expand the color space of the L * a * b * color system by printing with a combination of ink and further with the combination of the three colors of claim 1 and black ink. Ink printing method.   A printed matter obtained by printing using the osmotic drying type offset printing ink according to claim 1 by the printing method of the osmotic drying type offset printing ink according to claim 2.