JP2016210002A - Metallic image formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic image formation method which makes it possible to obtain a metallic image exhibiting a sufficient metallic feeling.SOLUTION: A metallic image formation method is characterized by applying an ink comprising an organic dye or a metal particle, exhibiting a metallic color, to a black recording medium to form a metallic image.SELECTED DRAWING: None

Description

  The present invention relates to a metallic image forming method.

  Conventionally, organic dyes that exhibit a metallic color have been studied for the purpose of expressing an image having a colored portion that emits a metallic color in printed matter such as printed advertisements and photographs (Patent Documents 1 to 5).

JP 2000-256357 A JP 2001-253882 A JP 2006-249259 A JP 2004-315545 A International Publication No. 2014/021405

  Therefore, the present inventor prepared an ink containing an organic dye exhibiting a metallic color and applied it to a recording medium to form an image. However, the metallic feeling was not sufficient, and a desired metallic image was not obtained.

  Accordingly, an object of the present invention is to provide a metallic image forming method capable of obtaining a metallic image exhibiting a sufficient metallic feeling.

  The above object is achieved by the present invention described below. That is, the metallic image forming method according to the present invention is characterized in that a metallic image is formed by applying an ink containing an organic dye or metal particles that exhibits a metallic color to a black recording medium.

  ADVANTAGE OF THE INVENTION According to this invention, the metallic image formation method which can obtain the metallic image which exhibits sufficient metallic feeling can be provided.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments.

First, the present inventors cannot obtain a sufficient metallic feeling simply by applying an ink containing an organic pigment exhibiting a metallic color (hereinafter also simply referred to as “metallic ink” or “ink”) to a recording medium. The reason was examined. As a result, specularly reflected light with respect to the incident light (reflected light reflected in the specular direction at the same reflection angle as the incident angle of the incident light) is reflected on the image in a metallic color but reflected at a reflection angle different from the regular reflected light It has been found that the metallic color is “turbid” due to the diffused light exhibiting a hue different from the metallic color. Based on this finding, the present inventors considered that a desired metallic feeling can be obtained if the diffused light can be reduced, and as a result of detailed studies, the present invention has been achieved. That is, in the present invention, by using a black recording medium as the recording medium to which the metallic ink is applied, the diffused light of the metallic ink can be absorbed and the diffused light can be reduced.
Below, the metallic image formation method of this invention and each material used with the method are demonstrated.

[Metallic image forming method]
<Ink application process>
The metallic image forming method of the present invention includes an ink application step of applying ink to a black recording medium. Hereinafter, the recording medium and the ink will be described.

(recoding media)
The recording medium used in the metallic image forming method of the present invention is black. In the present invention, “black” means that there is absorption in the entire region of the light wavelength of 380 nm to 780 nm. Further, when color measurement is performed using a D50 light source environment in a colorimetric method that does not include the specularly reflected light component of an integrating sphere spectrocolorimeter (in accordance with the measurement principle defined by the international standard of ISO7724 / 1, JIS Z 8722). The measurement is performed in accordance with the method described in the condition c described in 1. The measurement method includes an object color measurement method defined by CIE No. 15 of the International Lighting Commission, and ASTM standardized by the American Society for Testing Materials. In addition, in the CIEL ^* a ^* b ^* color system, the lightness L ^* is preferably 35 or less, more preferably 25 or less, and particularly preferably 15 or less. . When the lightness L ^* is 35 or less, the diffused light can be sufficiently reduced, and a natural metallic image can be obtained.

  In the present invention, a known material can be used as long as the recording medium is black. For example, a permeable recording medium such as plain paper, coated paper, art paper, cast coated paper and the like can be used. Further, a non-permeable recording medium such as a resin film such as a vinyl chloride sheet or a PET film can be used. The recording medium is not limited to these, and may be, for example, cloth, wood, plastic material, metal material, or the like.

(ink)
In the present invention, the ink contains an organic dye or metal particles that exhibit a metallic color on the recording medium. In the present invention, the “metallic color” means a metallic color having metallic luster such as gold, silver or copper.

(1) Organic Dye In the present invention, the “organic dye” is an organic compound that gives color to an object by absorption or emission of visible light, and may be a dye or a pigment. In the present invention, it is preferable to use a pigment. Examples of organic dyes that exhibit metallic colors include azamethine dyes, cyanine dyes, merocyanine dyes, xanthene dyes, azo dyes, quinacridone dyes, triphenylmethane dyes, phthalocyanine dyes, and pyrrole dyes ( Patent Documents 1 and 2), aniline dyes (described in Patent Documents 3 and 4), thiophene dyes (described in Patent Document 5), and the like. These organic pigments exhibiting a metallic color may be used alone or in combination.

Whether or not an organic dye exhibits a metallic color can be determined by the following procedure. First, an organic dye film is formed on a recording medium having a smooth surface (for example, a recording medium such as a quartz glass wafer having an arithmetic average roughness Ra of 0.001 μm or less). Examples of the film forming method include a dipping method, a spin coating method, a bar coating method, and a vapor deposition method. Next, using a variable angle spectrophotometer (for example, GSP-2 (manufactured by Murakami Color Co., Ltd.)), the angle dependency of the brightness L ^* representing the brightness of the formed film is measured, and the formula (A): An organic dye having a sharpness value represented by sharpness = L / w of 0.2 or more can be determined as “an organic dye exhibiting a metallic color”. Here, L represents the highest lightness value among the lightness L ^* measured by the light receiving unit of the variable angle spectrophotometer, and w represents the width of the light receiving angle at two points indicating a half value of L (L / 2). Represents. When the sharpness value is 0.2 or more, the brightness changes depending on the viewing angle, so that it is visually recognized as a metallic color. In order to exhibit a more excellent metallic color, the sharpness is preferably 0.4 or more, and more preferably 1.0 or more.

(2) Metal Particles In the present invention, “metal particles” are particles composed of one or more metal materials, and the metal material species is not particularly limited as long as it exhibits a metallic color on the recording medium. . The metal material constituting the metal particles is preferably gold, silver, or copper, and more preferably silver. The metal particles may be prepared by any method. For example, the metal particles can be suitably formed by preparing a solution containing metal ions and reducing the metal ions. Moreover, in order to form the aqueous dispersion of these metal particles, the above-mentioned various dispersants can be used as appropriate.

The particle size of the metal particles is preferably 3 nm or more, and more preferably 10 nm or more. When the particle size of the metal particles is less than 3 nm, the metallic color may not be exhibited on the recording medium. The particle size of the metal particles is preferably 130 nm or less, and more preferably 100 nm or less. When the particle size of the metal particles exceeds 130 nm, the dispersion stability of the metal particles in the ink may be deteriorated. The average particle diameter (D ₅₀ ) of the metal particles in the liquid can be measured using, for example, a dynamic light scattering type particle size distribution measuring apparatus. Examples of the dynamic light scattering type particle size distribution measuring apparatus include a trade name “FPAR-1000” (manufactured by Otsuka Electronics, cumulant method analysis), a trade name “UPA-EX150” (manufactured by Nikkiso), and a trade name “LB-550”. (Horiba Ltd.) can be used. Further, the particle diameter referred to here means “volume average particle diameter” measured by the above-described measuring method.

  In addition, the ink preferably contains a resin, an organic solvent, a surfactant, and water. The ink may be any one of a water-based ink containing 50% by mass or more of water and a non-aqueous ink containing less than 50% by mass of water. In addition to the above components, the ink may be a pH adjuster, an antifoaming agent, a rust inhibitor, an antiseptic agent, an antifungal agent, an antioxidant, a reduction inhibitor, an evaporation accelerator, a chelating agent, a water-soluble resin. Etc. may be contained. The components other than the organic coloring matter in the ink may be colored, but are preferably components that do not reduce the metallic color.

  In the present invention, the layer thickness derived from the metallic ink formed on the recording medium is preferably 0.01 μm or more, more preferably 0.03 μm or more, and even more preferably 0.05 μm or more when an organic dye is used. . Furthermore, it is preferably 100 μm or less, more preferably 10 μm or less, and even more preferably 1 μm or less. Moreover, when using a metal particle, 0.003 micrometer or more is preferable, 0.01 micrometer or more is more preferable, and 0.05 micrometer or more is further more preferable. Furthermore, it is preferably 100 μm or less, more preferably 10 μm or less, and even more preferably 1 μm or less.

(Ink application method)
In the image forming method of the present invention, a method for applying metallic ink is not particularly limited, and a known printing method or image forming method can be applied. For example, a printing method such as gravure printing, flexographic printing, offset printing, screen printing, letterpress printing, or an on-demand small printing method such as an ink jet method or a laser printed method can be given. Among these methods, the ink jet method is preferable because the ink can be easily applied to an arbitrary position on the recording medium.

  Below, an Example and a comparative example are given and this invention is demonstrated more concretely. In addition, this invention is not limited by the following Example, unless the summary is exceeded. Further, “part” or “%” in the following represents a mass standard unless otherwise specified. Also, when preparing the ink, the total of all the components was set to 100 parts.

[Comparative Example 1]
Dissolve 3 parts 2,2 ′-[1,4-phenylenebis [methylene (phenylimino) -4,1-phenylene]] bis-ethylenetricarbonitrile (see Patent Document 3) in 20 parts chloroform. To obtain a liquid mixture 1. Next, a KOH aqueous solution is added to a mixture of 5 parts of a styrene acrylic acid copolymer polymer dispersant (molecular weight 12000, acid value 170) and 500 parts of water to obtain a pH of 10 to prepare an aqueous solution of a resin dispersion. did. The liquid mixture 1 was added to the aqueous solution of the resin dispersion to obtain a liquid mixture 2. The mixture 2 was emulsified for 15 minutes with a sonic homogenizer to obtain an emulsion. Next, chloroform was distilled off under reduced pressure using an evaporator to obtain a dispersion of the compound. For inks containing organic pigments exhibiting a metallic color, a dispersion obtained so that the concentration of solids (compound and resin dispersant) in the ink is 5%, glycerin: 10 parts, acetylenol EH (product) Name: Kawaken Fine Chemical Co., Ltd.): 1.0 part, ion-exchanged water: remaining part was mixed to obtain an ink containing an organic dye exhibiting a metallic color.

For image formation, F930 (manufactured by Canon Inc., recording head; 6 ejection port arrays, 512 nozzles each, ink amount 4.0 pl (fixed), maximum resolution 1200 dpi (horizontal) × 1200 dpi (vertical)) was used. An ink cartridge of F930 was filled with an ink containing an organic pigment exhibiting a metallic color. And it printed so that it might become a solid image of 3 cm x 3 cm on the photographic paper for inkjet which is a recording medium (Canon photographic paper, glossy professional PR-201). When this recording medium was measured by the specular reflection light component removal (SCE) method of a spectrocolorimeter (trade name: CM-2600d, manufactured by Konica Minolta), L ^* = 93.8, a ^* = 0.7. B ^* = − 4.3.

When the image formed by the above-described image forming method was visually confirmed, the specular reflection light with respect to the incident light exhibited a gold color, but the diffused light other than the specular reflection light had a magenta color, and thus was an unnatural metallic image. Moreover, this image was measured by the specular reflection light component removal (SCE) system of a spectrocolorimeter (trade name: CM-2600d, manufactured by Konica Minolta). As a result, L ^* = 35.9, a ^* = 68.6, and b ^* = 0.4 in the CIEL ^* a ^* b ^* color system, confirming that the light was magenta diffuse light. Moreover, the film thickness of the ink containing the metal particle which exhibits the metallic color provided on the recording medium was 500 nm.

[Example 1]
The ink containing the organic pigment | dye which exhibits the metallic color as described in the comparative example 1 was used.

For image formation, F930 (manufactured by Canon Inc., recording head; 6 ejection port arrays, 512 nozzles each, ink amount 4.0 pl (fixed), maximum resolution 1200 dpi (horizontal) × 1200 dpi (vertical)) was used. An ink cartridge of F930 was filled with an ink containing an organic pigment exhibiting a metallic color. And it printed on the plain design paper (design paper) (TOCHIMAN TECH) which is a black recording medium so that it might become a solid image of 3 cm x 3 cm. When the black recording medium was measured by the specular reflection component removal (SCE) method of a spectrocolorimeter (trade name: CM-2600d, manufactured by Konica Minolta Co., Ltd.), L ^* = 25.7, a ^* = 0. 3. b ^* = 0.6.

When the image formed by the image forming method was visually confirmed, a metallic image exhibiting a natural golden metallic color was obtained for both regular reflection light and diffused light with respect to incident light. Moreover, this image was measured by the specular reflection light component removal (SCE) system of a spectrocolorimeter (trade name: CM-2600d, manufactured by Konica Minolta). As a result, in the CIEL ^* a ^* b ^* color system, L ^* = 33.3, a ^* = − 4.5, and b ^* = 12.0, and it was confirmed that magenta diffused light was reduced. Moreover, the film thickness of the ink containing the metal particle which exhibits the metallic color provided on the recording medium was 500 nm.

[Comparative Example 2]
For the ink containing metallic particles exhibiting a metallic color, a commercially available silver nanocolloid H-1 (manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) is used, and the solid content of the silver nanocolloid H-1 and the resin dispersant are contained in the ink. The silver nanocolloid H-1 was mixed with glycerol: 10 parts, acetylenol EH (trade name: manufactured by Kawaken Fine Chemicals Co., Ltd.): 1.0 part, and ion-exchanged water: the remainder so that the concentration was 5%. A thing was used. In addition, the average particle diameter of the silver nanocolloid H-1 is 32 nm by a dynamic light scattering particle size distribution analyzer LB-550 (manufactured by Horiba, Ltd.).

  For image formation, F930 (manufactured by Canon Inc., recording head; 6 ejection port arrays, 512 nozzles each, ink amount 4.0 pl (fixed), maximum resolution 1200 dpi (horizontal) × 1200 dpi (vertical)) was used. An ink cartridge of F930 was filled with an ink containing an organic pigment exhibiting a metallic color. And it printed so that it might become a solid image of 3 cm x 3 cm on the photographic paper for inkjet which is a recording medium (Canon photographic paper, glossy professional PR-201).

When the image formed by the image forming method was visually confirmed, the specularly reflected light with respect to the incident light exhibited a silver color, but the diffused light other than the specularly reflected light had a yellowish silver color, and thus was an unnatural metallic image. . Moreover, this image was measured by the specular reflection light component removal (SCE) system of a spectrocolorimeter (trade name: CM-2600d, manufactured by Konica Minolta). As a result, in the CIEL ^* a ^* b ^* color system, L ^* = 80.2, a ^* = 2.5, and b ^* = 18.9, confirming that the light was yellowish diffuse light. Moreover, the film thickness of the ink containing the metal particle which exhibits the metallic color provided on the recording medium was 100 nm.

[Example 2]
The ink containing metallic particles having a metallic color described in Comparative Example 2 was used.

  For image formation, F930 (manufactured by Canon Inc., recording head; 6 ejection port arrays, 512 nozzles each, ink amount 4.0 pl (fixed), maximum resolution 1200 dpi (horizontal) × 1200 dpi (vertical)) was used. The ink containing F930 ink cartridge was filled with ink containing metallic particles exhibiting a metallic color. And it printed on the plain design paper (design paper) (TOCHIMAN TECH) which is a black recording medium so that it might become a solid image of 3 cm x 3 cm.

When the image formed by the image forming method was visually confirmed, a metallic image exhibiting a natural silver metallic color was obtained for both regular reflection light and diffused light with respect to incident light. Moreover, this image was measured by the specular reflection light component removal (SCE) system of a spectrocolorimeter (trade name: CM-2600d, manufactured by Konica Minolta). As a result, in the CIEL ^* a ^* b ^* color system, L ^* = 33.5, a ^* = − 4.5, b ^* = 1.9, and it was confirmed that the yellowish diffused light was reduced. . Moreover, the film thickness of the ink containing the metal particle which exhibits the metallic color provided on the recording medium was 80 nm.

Claims (3)

  A metallic image forming method, wherein a metallic image is formed by applying an ink containing an organic pigment or metal particles exhibiting a metallic color to a black recording medium. 2. The method for forming a metallic image according to claim 1, wherein the black color has absorption in the entire light wavelength range of 380 nm to 780 nm, and the lightness L ^* in the CIEL ^* a ^* b ^* color system is 35 or less. . The metallic image forming method according to claim 1, wherein the ink is applied to the recording medium using an ink jet recording head.