Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
1999-05-13
2001-09-04
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031680, C106S031770, C106S031780, C106S031800, C106S031810, C106S031850
Reexamination Certificate
active
06284029
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a yellow ink composition, and more particularly to a yellow ink composition suitable for ink jet recording.
2. Background Art
Various properties are required of images produced by ink compositions, and one of them is lightfastness. When color images are produced using ink compositions, it is common practice to use at least a magenta ink, a yellow ink, and a cyan ink. Each of the inks should meet property requirements that are generally required of ink compositions, for example, stability of composition or properties upon storage. In addition, the inks should produce sharp images on recording media, and the images produced on the recording media should be stable upon storage for a long period of time.
In the production of color images using a plurality of ink compositions, presence of even one color having poor lightfastness causes a change in hue of the printed images. This results in remarkably deteriorated quality of color images. Therefore, more strictly controlled lightfastness is required of color ink compositions.
In recent years, ink jet recording printers have begun to widely spread. Ink jet recording is a printing method wherein droplets of an ink composition are ejected and deposited onto a recording medium, such as paper, to conduct printing. This method has a feature that images having high resolution and quality can be printed at a high speed by means of relatively inexpensive devices. In particular, color ink jet recording devices can provide images having improved quality, are used as output devices for photographs, and have become used as digital printing machines, plotters, CAD output devices and the like. Images printed by ink jet recording printers, which have become widely used, are considered usable in various forms. In particular, photograph-like prints produced by the ink jet recording printers are considered to be put as displays in places exposed to lights from fluorescent lamps or direct sunlight in outdoors and the like for a long period of time. Therefore, lightfastness is a very important property requirement for images produced by ink jet recording.
C.I. Pigment Yellow 74 has hitherto been widely used as a colorant for yellow ink compositons. This pigment is superior especially in yellow color development. However, there is still room for improvement in lightfastness.
Japanese Patent-Laid Open No. 25440/1998 proposes an ink composition, for ink jet recording, containing C.I. Pigment Yellow 154. This publication, however, discloses neither the addition of other pigments including C. I. Pigment Yellow 154 in combination with C.I. Pigment Yellow 74 to the ink composition nor advantages attained thereby.
SUMMARY OF THE INVENTION
The present inventors have now found that the lightfastness of a yellow ink containing C.I. Pigment Yellow 74 can be markedly improved by adding a second yellow pigment. 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 possessing excellent lightfastness and color development.
The yellow ink composition according to the present invention comprises C.I. Pigment Yellow 74 in combination with at least one second yellow pigment selected from the group consisting of C.I. Pigment Yellow 109, 110, 128, 150, and 154.
DETAILED DESCRIPTION OF THE INVENTION
The ink composition according to the present invention may be used in recording methods using an ink composition. Recording methods using an ink composition include, for example, an ink jet recording method, a recording method using writing utensils, such as pens, and other various printing methods. The ink composition according to the present invention is preferably used in the ink jet recording method.
The yellow ink composition according to the present invention can maintain excellent color development for a long period of time.
According to the present invention, the second yellow pigment is selected from the group consisting of C.I. Pigment Yellow 109, 110, 128, 150, and 154. The ratio of C.I. Pigment Yellow 74 to the second yellow pigment present in the ink composition is not particularly limited. However, the addition of C.I. Pigment Yellow 74 in a relatively large amount is preferred from the viewpoint of color development. The second yellow pigment is generally contained in an amount of 0.2 to 2 parts by weight based on the amount of C.I. Pigment Yellow 74. The upper limit of the amount of the second yellow pigment based on the amount of the C.I. Pigment Yellow 74 is preferably not more than 1 part by weight, more preferably not more than 0.8 part by weight.
The content of the pigment in the ink composition of the present invention is preferably about 1 to 10% by weight, more preferably about 2 to 7% by weight, in terms of the total amount of C.I. Pigment Yellow 74 and the second yellow pigment.
According to a preferred embodiment of the present invention, C.I. Pigment Yellow 74 and the second yellow pigment are added, to the ink, in the form of a pigment dispersion prepared by dispersing the pigment in an aqueous medium with the aid of a dispersant or a surfactant. Preferred dispersants include those commonly used in the preparation of a dispersion of a pigment, for example, a polymeric dispersant. In this connection, that the dispersant and the surfactant contained in the dispersion of the pigment function also as the dispersant and the surfactant for the ink composition will be apparent to a person having ordinary slcill in the art. Preferred examples of polymeric dispersants usable herein include naturally occurring polymers, and specific examples thereof include: proteins, such as glue, gelatin, casein, and albumin; naturally occurring rubbers, such as gum arabic and tragacanth; glucosides, such as saponin; alginic acid and alginic acid derivatives, such as propylene glycol alginate, triethanolamine alginate, and ammonium alginate; and cellulose derivatives, such as methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and ethylhydroxy cellulose. Preferred polymeric dispersants usable herein include synthetic polymers, and examples thereof include polyvinyl alcohols, polyvinyl pyrrolidones, acrylic resins, such as polyacrylic acid, acrylic acid/acrylonitrile copolymer, potassium acrylate/acrylonitrile copolymer, vinyl acetate/acrylic ester copolymer, and acrylic acid/acrylic ester copolymer, styrene/acrylic resins, such as styrene/acrylic acid copolymer, styrene/methacrylic acid copolymer, styrene/methacrylic acid/acrylic ester copolymer, styrene/&agr;-methylstyrene/acrylic acid copolymer, and styrene/&agr;-methylstyrene/acrylic acid/acrylic ester copolymer, styrene/maleic acid copolymer, styrene/maleic anhydride copolymer, vinylnaphthalene/acrylic acid copolymer, vinylnaphthalene/maleic acid copolymer, and vinyl acetate copolymers, such as 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, and salts of the above polymers. Among them, a copolymer of a monomer having a hydrophobic group with a monomer having a hydrophilic group and a polymer of a monomer having both a hydrophobic group and a hydrophilic group in its molecular structure are particularly preferred.
A preferred solvent usable in the ink composition according to the present invention comprises water and a water-soluble organic solvent. The water-soluble organic solvent is preferably a low-boiling organic solvent, and preferred examples thereof include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, sec-butanol, tert-butanol, iso-butanol, and n-pentanol. Monohydric alcohols are particularly preferred. The low-boiling organic solvent has the effect of shortening the time taken for drying the ink. The amount of the low-boiling organic solvent added is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, based on the ink.
According to
Sano Tsuyoshi
Takemoto Kiyohiko
Faison Veronica F.
Klemanski Helene
Ladas & Parry
Seiko Epson Corporation
LandOfFree
Yellow ink realizing image having excellent lightfastness... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Yellow ink realizing image having excellent lightfastness..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Yellow ink realizing image having excellent lightfastness... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2486663