Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2001-06-27
2004-03-09
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031780, C106S031810, C106S031860, C106S494000, C106S496000, C106S498000
Reexamination Certificate
active
06702883
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a yellow ink composition, an ink set, and a recording method using the same, which are excellent in a wide range of color reproduction and lightfastness
2. Background Art
Specific examples of pigments used in yellow inks include C.I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 128, 129, 138, 139, 150, 151, 154, 155, 180, and 185.
Although pigments are colorants which are generally superior in lightfastness to dyes, ink compositions have been desired which can realize images possessing a higher level of lightfastness. Further, in some cases, pigments are inferior in color development to dyes, and, in addition, when printing is performed using the pigments on recording media, images obtained are often somewhat unsatisfactory in vividness.
Further, for color images formed using a plurality of ink compositions, the presence of even one color ink composition having poor lightfastness results in a change in hue of images which in its turn extremely deteriorates the quality of color images. Therefore, more closely controlled lightfastness is also required for the yellow ink composition.
Further, for color images formed using ink compositions, it is a common practice to use magenta ink, yellow ink, cyan ink, and, in addition, optionally black ink. Color mixing of yellow with cyan can reproduce a green color, color mixing of yellow with magenta can reproduce a red color, and color mixing of cyan with magenta can reproduce a blue color. For this reason, the development of an ink set, which can realize faithful reproduction of these colors, has been desired.
SUMMARY OF THE INVENTION
The present inventors have now found that the preparation of a yellow ink composition comprising two yellow pigments, i.e., C.I. Pigment Yellow 128 and C.I. Pigment Yellow 110, can realize yellow images having significantly improved color reproduction and lightfastness. The present inventor shave further found that the use of an ink set comprising two yellow ink compositions respectively containing two pigments, i.e., C.I. Pigment Yellow 128 and C.I. Pigment Yellow 110, and an ink set comprising a combination of these two yellow ink compositions with a cyan ink composition, a magenta ink composition, or a black ink composition can realize yellow images, green images, red images, and, in its turn, color images, possessing significantly improved color reproduction and lightfastness. The present invention has been made based on such finding.
Accordingly, it is an object of the present invention to provide a yellow ink composition, a color ink set, and a recording method using the same, which can realize yellow images and, in its turn, color images possessing excellent color reproduction and lightfastness.
According to a first aspect of the present invention, there is provided a yellow ink composition. This ink composition comprises at least C.I. Pigment Yellow 128 and C.I. Pigment Yellow 110 as a colorant.
According to a second aspect of the present invention, there is provided an ink set comprising a first yellow ink composition and a second yellow ink composition, wherein the first yellow ink composition comprises C.I. Pigment Yellow 128 as a colorant, and the second yellow ink composition comprises C.I. Pigment Yellow 110 as a colorant.
According to a third aspect of the present invention, there is provided an ink set comprising a yellow ink composition and a cyan ink composition, a magenta ink composition, or a black ink composition, wherein
the yellow ink composition comprises a first yellow ink composition and a second yellow ink composition,
the first yellow ink composition comprises C.I. Pigment Yellow 128 as a colorant, and
the second yellow ink composition comprises C.I. Pigment Yellow 110 as a colorant.
DETAILED DESCRIPTION OF THE INVENTION
A. Yellow Ink Composition According to First Aspect of Present Invention
The yellow ink composition according to the present invention basically comprises C.I. Pigment Yellow 128 and C.I. Pigment Yellow 110 as a colorant. The formation of images using the yellow ink composition comprising these two yellow pigments can realize yellow images possessing excellent color reproduction and lightfastness.
According to a preferred embodiment of the present invention, the weight ratio of C.I. Pigment Yellow 128 to C.I. Pigment Yellow 110 is preferably 1 to 0.1:0.1 to 1. This can prepare a yellow ink composition which can realize good color reproduction of yellow images.
The content of the C.I. Pigment Yellow 128 in the ink composition according to the present invention and the content of C.I. Pigment Yellow 110 in the ink composition according to the present invention may be properly determined, however, the content is preferably about 1 to 5% by weight, more preferably 1.5 to 4% by weight, based on the ink composition.
The yellow ink composition according to the present invention basically comprises the above yellow pigments and may further comprise a dispersant, a surfactant, water, a water-soluble organic solvent, a penetrating agent, and other optional ingredients.
Dispersant/surfactant
According to a preferred embodiment of the present invention, the yellow pigments are added, to ink, as a pigment dispersion which is dispersed the yellow pigments in an aqueous medium with the aid of a dispersant or a surfactant. Preferred dispersants are dispersants commonly used in the preparation of pigment dispersions, for example, polymeric dispersants.
Examples of preferred dispersants include cationic dispersants, anionic dispersants, and nonionic dispersants. Examples of anionic dispersants include polyacrylic acid, polymethacrylic acid, acrylic acid/acrylonitrile copolymer, vinyl acetate/acrylic ester copolymer, acrylic acid/acrylic alkyl ester copolymer, styrene/acrylic acid copolymer, styrene/methacrylic acid copolymer, styrene/acrylic acid/acrylic alkyl ester copolymer, styrene/methacrylic acid/acrylic alkyl ester copolymer, styrene/&agr;-methylstyrene/acrylic acid copolymer, styrene/&agr;-methylstyrene/acrylic acid/acrylic alkyl ester copolymer, styrene/maleic acid copolymer, vinylnaphthalene/maleic acid copolymer, vinyl acetate/ethylene copolymer, vinyl acetate/fatty acid vinylethylene copolymer, vinyl acetate/maleic ester copolymer, vinyl acetate/crotonic acid copolymer, and vinyl acetate/acrylic acid copolymer. Examples of anionic sufactants include sodium dodecylbenzenesulfonate, sodium laurylate, and ammonium salt of polyoxyethylene alkyl ether sulfates. Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylphenyl ethers, polyoxyethylenealkylamines, and polyoxyethylene-alkylamides. They may be used alone or as a combination of two or more. According to a preferred embodiment of the present invention, the utilization of a water-soluble styrene-(meth)acrylic acid resin as a dispersant is preferred.
Water and Water-soluble Organic Solvent
The yellow ink composition according to the present invention contains water or a water-soluble organic solvent as a solvent. Examples of water-soluble organic solvents include high-boiling organic solvents. High-boiling organic solvents function to prevent drying of the ink composition and thus to prevent clogging of the head.
Examples of preferred high-boiling organic solvents include: polyhydric alcohols, such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, trimethylolethane, and trimethylolpropane; alkyl ethers of polyhydric alcohols, such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and triethylene glycol monobutyl ether; urea; 2-pyrrolidone and N-
Sano Tsuyoshi
Takemoto Kiyohiko
Klemanski Helene
Ladas & Parry
Seiko Epson Corporation
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