JP2008114398A - Lithographic printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing method which enables a representation of a color rendering region wider than ever by employing ink having a color reproducing region, which could not reproduce in conventional ink, in itself and further employing ink thicker than ever. <P>SOLUTION: This lithographic ink printing method consists of five colors by further adding one color of green ink to a lithographic printing method consisting of four process colors, yellow, magenta, cyan and black excellent in highly chromatic color reproducibility so as to realize color reproducing region wider than ever. An ink set and inks favorably can be employed for this printing method is provided. Further, a printed material printed by this printing method is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a lithographic ink printing method consisting of five colors, which is a lithographic ink printing method consisting of four colors of yellow, red, indigo and black, which has excellent color reproducibility with high saturation, and one additional green ink. In addition, the present invention relates to a lithographic printing method that enables a wider color reproduction region, an ink set and an ink that can be preferably used in these printing methods, and a printed matter printed by these printing methods.

  The IT revolution that began in the 1990s has rapidly led the environment surrounding the printing field in the direction of digitization. The workflow of the conventional printing method includes a large number of processes such as photographing, positive, scanning, data, design, EPS (Encapsulated PostScript), imposition, film, printing plate, and printing. On the other hand, the workflow of the digitized printing method includes processes such as photographing with a digital camera, DTP (Desk Top Publishing), CTP (Computer Top Plate), and printing. Through digitalization, we succeeded in dramatically shortening the printing workflow compared to conventional printing methods. In addition, the digitization of the input data “RGB” is becoming a standard, and the data to be handled is changing to a wider color reproduction region. In such an environment, “standardization” of the environment surrounding the printing site is an important point, and “Japan Color” is also attracting attention as one means of standardization.

  However, at present, lithographic offset printing using Japan color standard ink, which is the mainstream of printing, uses yellow, red, indigo and black ink process four-color (CMYK) inks. Therefore, in order to perform lithographic offset printing, data input as “RGB” must be color-converted (color separated) into “CMYK”. Since the hue of the printed material using process four-color ink is expressed by subtractive color mixing, the hue becomes cloudy each time the colors are overlapped, and the color reproduction region is necessarily narrower than that of “RGB”. In addition, depending on the selection of the standard for the “RGB” color space at the shooting stage, or depending on the color conversion method from “RGB” to “CMYK”, color reproduction may not be successful. Thus, the difference in color reproducibility between “RGB” digital data and printed matter using process four-color (CMYK) ink is a problem.

  In particular, the purple (blue violet, equivalent to RGB “B”) region expressed by two colors of red and indigo inks is more saturated than the case where the ink containing the purple pigment is expressed alone. The brightness is inferior. For this reason, it has been difficult to reproduce the “B” area of the “RGB” submission data using process four-color (YMCK) ink.

  Also, in particular, when yellow ink printed as the final color is opaque, a yellow fog phenomenon occurs, which has a large effect on each color of the underprint, and this also reproduces the “RGB” submission data. It is difficult. Accordingly, it is desirable that the yellow ink is as transparent as possible, and can produce a secondary color and a tertiary color with no turbidity when printed with other colors.

  As means for solving these problems, Patent Document 1 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 added to the process 4 colors, and 7 colors (high-fidelity printing with orange, green and purple added to the process 4 colors) An ink set made up of or the like is used.

  In hexachrome printing, not only primary colors but also secondary and tertiary colors can be prevented from becoming cloudy and the color reproduction area can be expanded by adding fluorescent pigments to some color inks. It has been. However, when this method is used, the printability is deteriorated (transfer failure, gloss reduction, etc.) and the printed matter is faded due to insufficient light resistance.

  In high-fidelity printing, in order to compensate for the three hues of orange, green, and purple that cannot be reproduced with the conventional four colors of processes, a total of seven color printing methods are used in which these three colors of ink are added.

However, 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 or more. Requires a color-separated version. Therefore, in order to newly start these methods, a large amount of capital investment, advanced color separation technology, complicated color tone management (print density, management of registration accuracy), etc. are required. The use is stopped.
JP 2001-260516 A

  The present invention has been made to solve any of the problems in the conventional technology. That is, the object of the present invention is to add green ink to the printing method using four process inks that can widen the color rendering area (gamut) than when printing ISO standard Japan color standard ink. By printing with five colors of ink, it is to provide a printing method that can reproduce the color area as close as possible to the color reproduction area of "RGB" more than the printed matter using Japan color standard ink. . 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.

  In general, in order to widen the color reproduction region, it is necessary to approximate the ideal spectral reflectance curve of each color.

  That is, the wavelength range in which a person recognizes color is 400 nm to 700 nm light (this wavelength is referred to as visible light). In yellow ink, the reflectance in the wavelength range of 500 nm to 700 nm is 100%, and the wavelength range of 400 nm to 500 nm. The red ink has a reflectance of 0%, and the red ink has a reflectance of 100% in the wavelength region of 400 nm to 500 nm and 600 nm to 700 nm, and a reflectance of 0% in the wavelength region of 500 nm to 600 nm. Therefore, it is said that it is ideal that the reflectance in the wavelength region of 400 nm to 600 nm is 100% and the reflectance in the wavelength region of 600 nm to 700 nm is 0% (the spectral reflectance of the ideal process ink) Curves are shown in Table 10).

However, the reflection spectrum of the ink composition for offset printing of yellow, red, indigo, and black, which is currently used in four process colors, is far from the ideal reflection spectrum. Since there is unnecessary absorption in the part that must be completely reflected, a turbid component of the ink exists, and the color reproducibility is narrowed.

  That is, the present invention is a lithographic printing method using an ink selected from yellow, red, indigo and black ink, in which three colors of yellow, red and indigo, yellow ink contains a disazo yellow compound as a coloring component, The red ink comprises a combination of lithographic inks characterized in that it contains a metal lake compound of a rhodamine dye as a coloring component, and the indigo ink contains a phthalocyanine compound as a coloring component. And a lithographic printing method using an ink selected from five color inks in which a green ink containing a halogenated phthalocyanine compound as a coloring component is combined.

  The present invention also provides CI pigment yellow 12 or CI pigment yellow 13 as a disazo yellow-based compound in an amount of 5 to 15% by weight based on the total weight of the ink, on a black ink having a density value of 1.85 to 1.90. Further, the present invention relates to the above-described lithographic printing method using a yellow ink having an L * value of 17 or less when repeatedly printed in a density range of 1.40 to 2.10.

  Further, the present invention uses a red ink containing CI Pigment Red 81, CI Pigment Violet 1 or CI Pigment Red 169 in an amount of 15 to 30% by weight based on the total weight of the ink as a metal lake compound of a rhodamine dye. The lithographic printing method described above.

  The present invention also relates to the lithographic printing method as described above, wherein as the phthalocyanine compound, indigo ink containing CI Pigment Blue 15: 3 or CI Pigment Blue 15: 4 in an amount of 10 to 25% by weight based on the total weight of the ink is used. About.

Furthermore, the present invention relates to the above-described lithographic printing method using the indigo ink containing CI Pigment Blue 15: 3 or CI Pigment Blue 15: 4 described above having a specific surface area of 74 m ² / g or more.

  Furthermore, the present invention relates to the lithographic printing method as described above, which uses indigo ink containing 0.5 to 2.0% by weight of C.I, Pigment Green 7 based on the total weight of the ink.

  The present invention also provides the lithographic printing method as described above, wherein the halogenated phthalocyanine compound uses a green ink containing 15 to 25% by weight of CI pigment green 7 or CI pigment green 36 based on the total weight of the ink. About.

  In addition, the coloring components (dyes and pigments) exemplified in the present invention may be used alone or in combination with two or more inks.

  Furthermore, the present invention relates to the lithographic printing method described above, wherein the reflectance of (a) yellow, (b) red, and (c) indigo is as follows.

(A) In the wavelength region of 400 nm to 700 nm, when the maximum reflectance is 100%, the wavelength region of 400 nm to 480 nm is 1 to 20%, and the reflectance in the wavelength region of 530 nm to 700 nm is 90 to 100%. A yellow ink containing 5 to 15% by weight of a coloring component having a reflection spectrum based on the total weight of the ink.

(B) In the wavelength region of 400 nm to 700 nm, when the maximum reflectance is 100%, the maximum reflectance in the wavelength region of 400 nm to 500 nm is 50% to 100%, 500 nm.
The reflectance in the wavelength region of ˜560 nm is 1 to 20%, and the reflectance of 630 nm to 700 nm is 9
A red ink containing 15 to 30% by weight, based on the total weight of the ink, of a coloring component having a reflection spectrum of 0% to 100%.

  (C) In the wavelength region of 400 nm to 700 nm, when the maximum reflectance is 100%, the reflectance in the wavelength region of 400 nm to 530 nm is 50 to 100%, and the reflectance of 600 nm to 700 nm is 1 to 30%. An indigo ink containing 10 to 25% by weight of a coloring component having a spectrum based on the total weight of the ink.

  Furthermore, the present invention relates to an ink set used for the lithographic printing method described above.

  Furthermore, this invention relates to the printed matter printed using the lithographic printing method described above.

  By using the lithographic ink composition provided by the present invention, conventionally, in addition to the Japanese color standard ink yellow, red, indigo and black ink process, 6 colors and 7 colors printing are added, such as orange, green, purple, etc. The RGB color reproduction area expressed in (4) can be made as close as possible with four colors of yellow, red, indigo, and black and green, which have a wider color rendering area than Japan color standard ink.

  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.

  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 lithographic ink comprising five colors of yellow, red, indigo, black, and green is used, and the ink of the present invention can be produced by a conventionally known method.

The ink used in the present invention is printed on ISO standard Japan color standard paper, for example, “Tokuhishi art double sided paper size / 110 kg” manufactured by Mitsubishi Paper Industries Co., Ltd., and yellow, red, and indigo colors are manufactured by Gretag Macbeth Co., Ltd. Concentration values measured with a SpectroEye densitometer (light source D50, 2-degree field of view, measuring optics 45 ° / 0 °, density reference DIN16536, no polarizing filter, absolute blank reference) are 1.40 to 1.44 for yellow L ^* a ^* b ^* values for each color when red is printed in a single range within the range of 1.52-1.56 for red and 1.63-1.67 for indigo (reference density), and yellow L ^* a ^* b ^* value of each color when two types selected from red and indigo inks are solid-printed at a standard density is yellow ink, L ^* : 87 to 95, preferably 88 to 93, a ^* : -4 to -12, preferably -5 to -10, b ^* : 90 to 100, preferably 92 to 98, red in L ^* : 50 to 55, preferably 51 to 54, a ^* : 75 to 83, preferably 76 to 81, b ^* : -14 to -20, preferably -15 to -18, indigo ink, L ^* : 52 to 58, preferably 52 to 57, a ^* : −35 to −45, preferably −38 to −44, b ^* : −45 to −53, preferably −46 to −51, L ^* : 51-56, a ^* : 65-70, b ^* : 56-61, indigo ink x yellow ink, L ^* : 47-53, a ^* : -77 to -83, b ^* : 20 to 32, indigo ink x red ink, and L ^* : 23 to 31, a ^* : 23 to 33, b ^* : within the range of -63 to -70 It is characterized by becoming.

In addition, the green ink generally has no standard density value set, but in the present invention, the density value when measured as the density of indigo ink with a SpectroEye densitometer manufactured by Gretag Macbeth is 1.60. The L ^* a ^* b ^* value of the monochromatic solid portion in the range of 2.20 is L ^* : 50 to 65, preferably 55 to 63, a ^* : −73 to −87, preferably −75 to − 85, b ^* : 0 to 10, preferably 0 to 5.

Next, Japan Color is a standard color for printing established by the ISO / TC130 National Committee. In Japan Color Reproduction Printing 2001, colorimetric values (L ^* a ^* b ^* values) of ISO12642 patterns (928 colors, also referred to as IT8) are shown as data. As printing conditions for reproducing this Japan color reproduction reproduction 2001, standard conditions of the international standard ISO12647-2 regarding commercial offset printing are used. As ink and printing paper, ink and printing paper that are normally used in Japan are used (four kinds of paper are determined in Japan Color 2001). General Japan color standard ink (for example, “Toyo Ink Manufacturing Co., Ltd.“ TK High Unity each color ”) and Japan color standard paper (for example,“ Mr. The L ^* a ^* b ^* values of the single-color solid portions of yellow, red, and indigo when printed on and the C value calculated from them are L ^* : 86, a ^* : −7, b ^* : 92, C: about 92, for red ink, L ^* : 45, a ^* : 72, b ^* : -5, C: about 72, for indigo ink, L ^* : 54, a ^* : -36 , B ^* : −49, C: about 61.

  The Japan color standard ink is a Japanese standard ink determined as follows. First, on behalf of the TC130 National Committee, the Printing Ink Industry Association measured and aggregated the color characteristics of representative process inks of eight ink manufacturers that belonged to it. In response, the TC130 National Committee determined a standard spectral reflection curve for the process ink. The ink that embodies this standard spectral reflection curve was designated as Japan Color Standard Ink. For example, as offset sheet-fed ink, there is “each color of TK high unity” manufactured by Toyo Ink Manufacturing Co., Ltd.

The Japan color standard paper is a Japanese standard paper determined as follows. First, the average optical characteristic value of art paper surfaces of six domestic paper manufacturers was defined as “standard characteristic value of Japan Paper”. Two companies' art papers having characteristics close to the standard characteristic values were defined as Japan color standard paper. Currently, Japan Color Standard Paper has the following optical properties: whiteness: 80 ± 5 (%), glossiness: 75 ± 2 (%), L ^* : 93.0 ± 3, a ^* : 0.5 ± 2, b ^* : 0.4 ± 2. The Japan color standard paper is equivalent to ISO standard paper type 1 which defines offset printing process management.

  “Japan Color Reproduction Printing 2001” uses four types of paper, art paper, coated paper, matte coated paper, and high-quality paper, which are domestic ISO standard products. Examples of the art paper include “OK Kanfuji N” manufactured by Oji Paper Co., Ltd., “NPI Special Art” manufactured by Nippon Paper Industries Co., Ltd., and “Tokuhishi Art Both Sides N” manufactured by Mitsubishi Paper Industries Co., Ltd. Examples of the coated paper include Oji Paper Co., Ltd. “OK Top Coat N”, Nippon Paper Industries Co., Ltd. “NPI Coat”, and Mitsubishi Paper Industries Co., Ltd. “Pearl Coat”. Examples of the mat coated paper include “OK Top Coat Mat” manufactured by Oji Paper Co., Ltd., “Ulite” manufactured by Nippon Paper Industries Co., Ltd., and “New V Mat” manufactured by Mitsubishi Paper Industries Co., Ltd. Examples of the quality paper include “OK Prince Quality” manufactured by Oji Paper Co., Ltd., “New NPO Quality” manufactured by Nippon Paper Industries Co., Ltd., and “Kinryo” manufactured by Mitsubishi Paper Industries Co., Ltd.

  In the present invention, when evaluating ink characteristics such as density and L * a * b * value, ISO standard Japan color standard paper (for example, “Special” manufactured by Mitsubishi Paper Industries Co., Ltd.) is used as paper for printing ink. Rhizo Art Double Sided 46th Edition / 110 kg ") can be used. In addition, the paper used when actually performing lithographic printing using the method of the present invention or the ink set of the present invention is not limited to Japan color standard paper. Any paper such as the above-mentioned art paper, coated paper, matte coated paper, and high-quality paper can be used. Art paper is preferable.

  In the present invention, “density value” refers to ISO standard Japan color standard paper (for example, “Special Rhibo Art Double Sided Plates / 110 kg” manufactured by Mitsubishi Paper Industries Co., Ltd.), yellow, red, indigo and black ink. Is a solid print, and each of yellow, red, indigo and black is measured with a Gretag Macbeth SpectroEye densitometer (manufactured by Gretag Macbeth).

As a method for expressing the color reproduction region, an XYZ color system (CIE 1931 color system), X ₁₀ Y ₁₀ Z _1
0 color system (CIE 1964 color system), L ^* a ^* b ^* color system (CIE 1976), Hunter Lab color system, Munsell color system, L ^* u ^* v ^* color system (CIE 1976), etc. .

In the L ^* a ^* b ^* color system, "lightness" is expressed as L ^* as the degree of brightness that can be compared regardless of hue, and it indicates that the color becomes brighter as L ^* increases and becomes darker as it decreases. . In addition, “hue” which 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.

Similarly, C shows that the color becomes brighter as the absolute value increases, and the color becomes dull as the value decreases.
Furthermore, subtle color differences (color differences) can be expressed numerically using numerical values of individual colors expressed in the L ^* a ^* b ^* color system. The color difference (expressed as “ΔE”) between the two colors can be obtained by the following calculation formula.

  As the absolute value of ΔE is smaller, the two colors are closer to each other, and as the absolute value of ΔE is larger, the two colors are different.

In order to obtain a color rendering area (gamut) using the L ^* a ^* b ^* color system, first, a color chart such as ISO 12642 chart (IT8 chart) using yellow, red, indigo, black and other inks. Was printed, and the L * a * b * values of each color of the chart (928 colors in the case of ISO12642 chart) were measured using a spectrophotometer (Spectro Lino, manufactured by Gretag Macbeth) (measurement conditions: light source D50, 2-degree field of view) , Measurement optics 45 ° / 0 °, absolute blank paper conditions), and an ICC profile is created from the measurement result using ProfileMaker of Gretag Macbeth. As the paper on which the ink is printed, ISO standard Japan color standard paper (for example, “Tokuhishi Art Double Sided 46th Edition / 110 kg” manufactured by Mitsubishi Paper Industries Co., Ltd.) can be used.

  Next, using the created ICC profile, the RGB image color reproducible area is represented on the screen by Adobe Photoshop, or the 3D gamut diagram (L * a * b) using CHROMIX ColorThink. * Color system) can be created.

While all of the color reproduction area that can be represented by one of the printed matter (including color space other than the printed matter) is referred to as color rendering area (gamut), as the most convenient way to represent the gamut, the horizontal axis represents a ^*, and 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 ^* values, It can be expressed by the plotted hexagonal area. The larger the gamut area, the wider the color reproduction area.

  As a printing method used in the present invention, a conventionally known lithographic printing method is used. Examples include offset sheet-fed printing, offset rotary printing, waterless offset printing, and dry offset printing.

  As the ink set used in the present invention, a conventionally known lithographic printing ink is used. For example, an oxidation polymerization type ink, a heat set type ink, a osmotic drying type ink, an ultraviolet curable type ink and the like can be mentioned.

  A conventionally known plate making technique is also used for the plate used for printing. Examples thereof include a plate formed by an amplitude modulation screening (AM screening) method, a plate formed by a frequency modulation screening (FM screening) method, and the like.

Regarding the yellow ink used in the present invention, the L * value when overprinted in the density range of 1.40 to 2.10 on the black ink printed within the density value range of 1.85 to 1.90 is If the transparency does not exceed 17, there is little influence on the underprinting ink when the secondary and tertiary colors are overprinted, and a good color reproduction region can be obtained. Further, CI Pigment Yellow 83 can be used as a complementary color by adding 0.5 to 10% by weight, preferably 2 to 5% by weight, based on the total weight of the yellow pigment.

  As the yellow pigment used in the present invention, C.I. Pigment Yellow 12 or C.I Pigment Yellow 13 is preferably used in an amount of 5 to 15% by weight based on the total weight of the ink.

  Examples of red pigments used in the present invention include, but are not limited to, rhodamine-based dyes such as rhodamine B, rhodamine 3G and rhodamine 6G, molybdenum and tungsten metal lake compounds. C.I. Pigment Red 81, C.I. Pigment Violet 1 or C.I. Pigment Red 169 ink is preferably contained in an amount of 15 to 30% by weight. These may be used alone or in combination of two or more.

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.

  In the present invention, the halogenated copper phthalocyanine compound in which the hydrogen atom on the benzene ring of the phthalocyanine molecule is substituted with a halogen compound as a complementary color with respect to the total weight of the copper phthalocyanine compound is preferably 5 to 15% by weight, more preferably 8 to 11% by weight. % Can be used, and this makes it possible to widen the color reproduction area of green and purple when overprinted with yellow and red ink without impairing the color reproduction area of indigo ink single color. .

  Specifically, CI Pigment Blue 15: 3 or CI Pigment Blue 15: 4 is preferably contained in an amount of 10 to 25% by weight based on the total weight of the ink. Further, CI Pigment Green 7 is used as a complementary color. It is also possible to use 0.5 to 2.0% by weight based on the weight.

  Examples of the green pigment used in the present invention include halogenated phthalocyanine compounds. The most frequently used is chlorinated copper phthalocyanine, and there are others that contain bromine instead of chlorine, those that contain chlorine and bromine, and those that do not contain copper.

  Specifically, C.I. Pigment Green 7 or C.I. Pigment Green 36 is preferably contained in an amount of 15 to 25% by weight, preferably 16 to 23% by weight, more preferably 18 to 22% by weight, based on the total weight of the ink. Furthermore, these may be used independently and can also be used in combination of 2 or more types.

  Examples of black pigments include carbon black such as C.I. I. Pigment black 7 and the like. Two or more pigments can be used in combination. The content of the black pigment (when using a combination of pigments, the total content) is preferably 10 to 30% by weight, more preferably 15 to 25% by weight, based on the total weight of the ink. More preferably, it is 16 to 20% by weight.

Examples of the synthetic resin used in the present invention include rosin-modified phenol resin, petroleum resin, alkyd resin, rosin-modified alkyd resin, petroleum resin-modified alkyd resin, and rosin ester. 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%,
Since the ability to dissolve the resin is too high, the setting property of the ink becomes slow, which is not preferable.
When the temperature exceeds 5 ° C., the resin is poorly soluble, so that the gloss and the inking are deteriorated.
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. Moreover, when it exceeds 350 degreeC, since drying of heat set type ink is inferior, it is unpreferable.

Further, the lithographic ink composition of the present invention includes a gelling agent, a pigment dispersant, a metal dryer, a drying inhibitor, an antioxidant, an anti-friction agent, an anti-set-off agent, and a nonionic surfactant as required. Additives such as agents and polyhydric alcohols can be used as appropriate.
〔Example〕
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%.

Example of production of rosin-modified phenolic resin To a four-necked flask equipped with a stirrer, a cooler, and a thermometer, 1000 parts of P-octylphenol, 850 parts of 35% formalin, 60 parts of 93% sodium hydroxide, 1000 parts of toluene, The reaction was carried out at 90 ° C. for 6 hours. Then, 125 parts of 6N hydrochloric acid and 1000 parts of tap water were added, stirred and allowed to stand, and the upper layer part was taken out to obtain 2000 parts of a toluene solution of a resole type phenol resin having a nonvolatile content of 49%. It was.

  A four-necked flask equipped with a stirrer, a condenser with a water separator, and a thermometer was charged with 1000 parts of gum rosin, dissolved at 200 ° C. while blowing nitrogen gas, and 1800 parts of the resole solution produced above was added. After reacting at 230 ° C. for 4 hours while removing toluene, 110 parts of glycerin was added, and reacted at 260 ° C. for 10 hours, with an acid value of 20 or less, a weight average molecular weight of 50000, Shin Nippon Petrochemical Co., Ltd. AF Solvent 6 A rosin-modified phenol resin having a cloudiness temperature of 90 ° C. was obtained.

Example of varnish production 40 parts of rosin-modified phenol resin, 30 parts of soybean oil, 10 of tung oil, 19 parts of AF solvent 6 (solvent manufactured by Nippon Petrochemical Co., Ltd.), ALCH (gelator manufactured by Kawaken Fine Chemical Co., Ltd.) 1 0.0 part was heated and stirred at 190 ° C. for 1 hour to obtain a varnish.

Ink example (yellow ink)
In the formulation shown in Table 1, C.I. I. Pigment Yellow 12 (LI made by Toyo Ink Manufacturing Co., Ltd.)
ONOL YELLOW 1235-P) was subjected to primary dehydration by gradually adding 60 parts of varnish and kneading 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 varnish and petroleum solvent were added, kneaded and diluted, and the undispersed base ink was taken out from the kneader. The extracted base ink is kneaded with a three roll with a roll temperature of 60 ° C. until the particle size of the pigment becomes 7.5 microns or less with a dispersion particle system measuring machine (grind meter). Obtained. Next, varnish, soybean oil, petroleum solvent, compound, metal dryer, and drying inhibitor 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.). Next, soybean ink, petroleum solvent, compound, metal dryer, and drying inhibitor were added to the base ink 2 in the formulation shown in Table 2 to obtain red ink 2.

Ink Example (Red ink)
C. in the formulation of Table 1 I. Pigment Red 169 (FanalPink D 4810 manufactured by BASF) is mixed with varnish and petroleum solvent, and the base ink of red meat and red is used until the particle size of the pigment becomes 7.5 microns or less with a dispersion particle measuring machine (grind meter). 3 was obtained. Next, to this base ink 3, soybean oil, petroleum solvent, compound, metal dryer, and drying inhibitor were added in the formulation shown in Table 2 to obtain red ink 3.

Ink Example (Indigo Ink)
In the formulation of Table 1, C.I. I. Pigment Blue 15: 3 (LIO manufactured by Toyo Ink Manufacturing Co., Ltd.)
NOL BLUE GLA-SD: specific surface area 74.625 m ² / g) is mixed with varnish and petroleum solvent, and the mixture is ground until the particle size of the pigment is 7.5 microns or less with a dispersion particle measuring machine (grind meter) Indigo base ink 4 was obtained. Subsequently, soybean oil, petroleum solvent, compound, metal dryer, and drying inhibitor were added to the base ink 4 in the formulation shown in Table 2 to obtain indigo ink 4.

Ink Example (Indigo Ink)
C. in the formulation of Table 1 I. Pigment Green 7 (LIONOL GREEN Y-101 manufactured by Toyo Ink Mfg. Co., Ltd.) is mixed with varnish and petroleum solvent until the particle size of the pigment is 7.5 microns or less with a dispersion particle measuring machine (grind meter). After mixing kneaded base ink 5 with indigo base ink 4 and base ink 5 according to the composition shown in Table 2, soybean oil, petroleum-based solvent, compound, metal dryer, and drying inhibitor were added, and indigo ink was added. 5 was obtained.

Ink example (green ink)
Green ink 6 was obtained by adding soybean oil, petroleum-based solvent, compound, metal dryer and drying inhibitor to the base ink 5 obtained by the blending of Table 1 according to the blending of Table 2.

Ink example (green ink)
C. in the formulation of Table 1 I. Pigment Green 36 (LIONOL GREEN 2YS manufactured by Toyo Ink Mfg. Co., Ltd.) is mixed with varnish and petroleum solvent, and the mixture is kneaded until the particle size of the pigment becomes 7.5 microns or less with a dispersion particle measuring machine (grind meter). As a result, a green base ink 6 was obtained. Next, in the formulation of Table 2, to this base ink 6, soybean oil, petroleum solvent, compound, metal dryer, and drying inhibitor were added in the formulation of Table 2 to obtain a green ink 7.

Ink comparison example (yellow ink)
In the formulation shown in Table 1, C.I. I. Pigment Yellow 12 (LI made by Toyo Ink Manufacturing Co., Ltd.)
ONOL YELLOW 1229-P) was subjected to primary dehydration by gradually adding 660 parts of varnish and kneading 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 varnish and petroleum solvent were added, kneaded and diluted, and the undispersed base ink was taken out from the kneader. The extracted base ink is kneaded using a three roll with a roll temperature of 60 ° C. with a dispersion particle measuring machine (grind meter) until the particle size of the pigment becomes 7.5 microns or less. Obtained. Next, varnish, soybean oil, petroleum solvent, compound, metal dryer, and drying inhibitor were added to the base ink 7 in accordance with the formulation shown in Table 2 to obtain a yellow ink 8.

Ink comparison example (red ink)
As with the yellow ink, C.I. I. Pigment Red 57: 1 (LIONOL RED 6B 4240-P manufactured by Toyo Ink Manufacturing Co., Ltd.) was used to obtain red base ink 8. Next, soybean ink, petroleum solvent, compound, metal dryer, and drying inhibitor were added to the base ink 8 in accordance with the formulation shown in Table 2 to obtain a red ink 9.

Ink comparison example (indigo ink)
C. in the formulation of Table 1 Indigo base ink 9 was obtained using I Pigment Blue 15: 3 (LIONOL BLUE FG7330: specific surface area 71.750 m ² / g manufactured by Toyo Ink Manufacturing Co., Ltd.). Next, soybean oil, petroleum solvent, compound, metal dryer, and drying inhibitor were added to the base ink 9 in the formulation shown in Table 2 to obtain indigo ink 10.

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

  Yellow ink is printed in the density range of 1.40 to 2.10 on black ink (TK high unity ink manufactured by Toyo Ink Co., Ltd.) printed within the density value range of 1.85 to 1.90. , L * was measured. The results are shown in Table 3. The yellow ink of the example does not exceed L * even when the density value is increased to 2.20, hardly affects the black ink of the underprint, and can be said to have excellent transparency (L * has a value) The smaller the color, the more black it is, and the larger the color, the whiter it is). On the other hand, in the comparative example, L * is high, and it can be seen that the black ink of the underprinted black ink is hindered because the yellow ink of the overprinted is opaque.

  In addition, about the specific surface area, the value computed by the following formula | equation from the surface area measured using the flow type specific surface area measuring apparatus "Flowsorb II" by Shimadzu Corporation was defined and described.

Specific surface area (m2 / g) = surface area (m2) / powder mass (g)

Printing Evaluation Test The inks of the above Examples and Comparative Examples were evaluated according to the contents in Table 4.
In addition, the general oxidation polymerization type lithographic printing ink (TK high unity ink made by Toyo Ink Manufacturing Co., Ltd.) was used as the black ink of Examples and Comparative Examples.

Printing conditions Printing machine: Heidelberg Speedmaster Kikuzen 5-color machine (Heidelberg Japan (
stock))
Paper: Tokishi Art Double Sided 110Kg (Mitsubishi Paper Co., Ltd.)
Dampening solution: Astro Mark 3 (Niken Chemical Research Co., Ltd.) 2.0% tap water printing speed: 10,000 sheets / hour Concentration: Yellow: 1.40-1.44, Red: 1.52-1. 56, indigo: 1.63 to 1.67, black: 1.85 to 1.90, adjusted to a solid density and printed. For green ink, the solid density is 1.60 to 2.20. It was printed so that it would be in the range (as indigo density).

Printed material measurement conditions Density: SpectroEye (Gretag Macbeth, light source D50, 2 degree field of view, measuring optics 45 ° / 0 °, density standard DIN16536, no polarizing filter, absolute blank paper standard) single color (yellow, red, indigo) , Black, green) Measure the density value of the solid part Colorimetry: Monochrome of printed matter with SpectroEye (Gretag Macbeth, light source D50, 2 degree field of view, measuring optics 45 ° / 0 °, no polarizing filter, absolute blank paper standard) Measure L ^* , a ^* , b ^* values of solid part (yellow, red, indigo, green) and single color solid print overprinted part (yellow x red, red x indigo, indigo x yellow). The C value was obtained from a ^* and b ^* by the following formula.

  The results are shown in Table 5. Compared with the comparative example, the C value of the example is large and the saturation of the printed matter is high.

Also, each a ^* and b ^* value was plotted in a two-dimensional space with a ^* as the horizontal axis and b ^* vertical axis, and compared with a two-dimensional gamut. (Table 6 to Table 9)
In the comparison between Examples 1 to 4 and Comparative Example 1, two-dimensional gamuts were compared when four-color printing of yellow red and black ink was performed (Table 6). Compared to Comparative Example 1, all the combinations of Examples 1 to 4 have a wide color reproduction region.

  Furthermore, the gamut of Examples 5-12 which combined green ink with the combination of Examples 1-4 and Comparative Examples 2-3 which combined green ink with Comparative Example 1 was compared (Table 7: Examples 5-8). And Comparative Example 2, Table 8: Examples 9-12 and Comparative Example 3).

  Furthermore, Table 9 shows a gamut diagram comparing Example 1 and Example 5. By adding green ink to four-color ink with a wide color reproduction area, the color reproduction area is further expanded.

In addition, Table 11 shows the obtained spectral reflectance curve. Compared to the conventional ink of the comparative example, the ink of the example is closer to the ideal spectral reflectance curve, and unnecessary absorption of the portion that must be completely reflected is reduced. For this reason, the turbidity component of the ink is reduced and the color reproduction region is widened.

Therefore, in the present invention, a printing method capable of expressing a wider color rendering region by using a printing method in which the ink itself has a color reproduction region that could not be reproduced by conventional inks and further increases the density. I found.

Claims (10)

  In a lithographic printing method using an ink selected from yellow, red, indigo and black ink, yellow, red and indigo are three colors, yellow ink contains a disazo yellow compound as a coloring component, and red ink is colored Containing a metal lake compound of a rhodamine dye as a component, and the indigo ink comprising a combination of lithographic inks characterized by containing a phthalocyanine compound as a coloring component. A lithographic printing method comprising using an ink selected from five color inks combined with a green ink containing a halogenated phthalocyanine compound as a component. As a disazo yellow compound, CI pigment yellow 12 or CI pigment yellow 13 is contained in an amount of 5 to 15% by weight based on the total weight of the ink, and the density is 1.40 to 1.40 on the black ink having a density value of 1.85 to 1.90. 2. The lithographic printing method according to claim 1, wherein a yellow ink having an L ^* value of 17 or less when printed in the range of 2.10 is used.   A red ink containing CI Pigment Red 81, CI Pigment Violet 1 or CI Pigment Red 169 in an amount of 15 to 30% by weight based on the total weight of the ink is used as a metal lake compound of a rhodamine dye. The planographic printing method according to claim 1.   2. Lithographic printing according to claim 1, wherein the phthalocyanine compound is a cyan ink containing CI Pigment Blue 15: 3 or CI Pigment Blue 15: 4 in an amount of 10 to 25% by weight based on the total weight of the ink. Method. The lithographic printing method according to claim 1 or 4, wherein the indigo ink containing CI pigment blue 15: 3 or CI pigment blue 15: 4 having a specific surface area of 74 m ² / g or more is used.   5. The lithographic printing method according to claim 1, wherein the cyan ink contains 0.5 to 2.0% by weight of C.I, Pigment Green 7 based on the total weight of the ink.    2. The lithographic printing according to claim 1, wherein the halogenated phthalocyanine compound is a green ink containing 15 to 25% by weight of CI Pigment Green 7 or CI Pigment Green 36 based on the total weight of the ink. Method. The lithographic printing method according to any one of claims 1 to 6, wherein the reflectance of (a) yellow ink, (b) red ink, and (c) indigo ink is as follows.
(A) In the wavelength region of 400 nm to 700 nm, when the maximum reflectance is 100%, the wavelength region of 400 nm to 480 nm is 1 to 20%, and the reflectance in the wavelength region of 530 nm to 700 nm is 90 to 100%. A yellow ink containing 5 to 15% by weight of a coloring component having a reflection spectrum based on the total weight of the ink.
(B) In the wavelength region of 400 nm to 700 nm, when the maximum reflectance is 100%, the maximum reflectance in the wavelength region of 400 nm to 500 nm is 50% to 100%, 500 nm.
The reflectance in the wavelength region of ˜560 nm is 1 to 20%, and the reflectance of 630 nm to 700 nm is 9
A red ink containing 15 to 30% by weight, based on the total weight of the ink, of a coloring component having a reflection spectrum of 0% to 100%.
(C) In the wavelength region of 400 nm to 700 nm, when the maximum reflectance is 100%, the reflectance in the wavelength region of 400 nm to 530 nm is 50 to 100%, and the reflectance of 600 nm to 700 nm is 1 to 30%. An indigo ink containing 10 to 25% by weight of a coloring component having a spectrum based on the total weight of the ink.   The ink set used for the lithographic printing method in any one of Claims 1-8. A printed matter printed using the planographic printing method according to claim 1.