Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-09-11
2004-08-24
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S095000, C106S031130, C106S031270
Reexamination Certificate
active
06779881
ABSTRACT:
TECHNICAL FIELD
This invention relates to an ink, an ink set, and an ink jet recording method that are particularly favorable for ink jet recording.
BACKGROUND ART
As is commonly known, ink jet recording is a method in which printing is performed by causing droplets of ink to fly out and adhere to a recording medium such as paper. This printing method allows images of high resolution and quality to be printed quickly and simply with an inexpensive apparatus, and particularly in the field of color printing, this image formation method has in recent years been the subject of technological development as an alternative to photography.
When a color image is formed by ink jet recording, the printing is performed using inks of at least the three primary colors of magenta, yellow, and cyan, but more recently it has become commonplace to obtain a more detailed image by using light and dark inks of different density for the magenta ink and cyan ink in order to obtain a higher-quality image. It is important that these inks themselves have excellent color reproducibility, and achieving good color reproducibility is also important when two or more inks selected from among magenta ink, yellow ink, and cyan ink are printed on top of each other and red, green, blue, and black are formed.
In the past these ink-jet inks have mainly consisted of water-based inks, in consideration of odor and safety (e.g., fire hazards). Among the properties required of these inks are that their viscosity, surface tension, and other such physical properties be within a suitable range, that they have excellent storage stability and do not clog the nozzle, that they give a high-density recorded image, and that they have excellent light fastness, water resistance, and moisture resistance.
Most of these performance requirements can be satisfied by using a water-based ink in which the main solvent is water or a mixture of water and a water-soluble organic solvent, but color, clarity, light fastness, water resistance, moisture resistance, and so forth are greatly affected by the colorant, and many different dyes have been researched up to now.
In particular, with a color recording method that makes use of inks of a number of colors, all of the inks used must have uniform characteristics. Fading and color changes caused by light (sunlight, fluorescent light, etc.) is particularly pronounced with magenta dyes, more so than with other dyes (cyan and yellow dyes). Therefore, the inferior light fastness of a magenta ink compared to that of other inks means that not only will this inferiority be apparent with the magenta ink by itself, but also in secondary colors (such as red and blue) expressed by superposing yellow ink or cyan ink, and this leads to a change in the color of the overall image in recorded material, and a loss of quality.
Acid dyes that are highly water soluble and have good color development, such as C.I. Acid Red 52, 249, and 289, have been known in the past as magenta dyes for use in ink jet recording, but although nozzle clogging tended not to occur when these dyes were used alone because of their high water solubility, their light fastness performance was extremely poor.
In response to these requirements, Japanese Laid-Open Patent Applications H6-228447, H8-90211, H8-73791, H10-306221 and so forth have disclosed a magenta dye ink with excellent light fastness, water resistance, moisture resistance, color, clarity, and so on.
Still, light fastness, water resistance, vivid color and color reproducibility, nozzle clogging resistance, and so forth could not all be satisfied at the same time with inks in which these magenta dyes proposed in the past were used.
It has also been disclosed, in Japanese Laid-Open Patent Applications H5-214259 and 2001-115072, that excellent color reproducibility and light fastness can be obtained even with secondary or tertiary colors by using an ink set that makes use of a specific dye set.
However, light fastness, water resistance, vivid color and color reproducibility, nozzle clogging resistance, and so forth could not all be satisfied at the same time with inks in which these ink sets proposed in the past were used.
It is therefore an object of the present invention to provide an ink, an ink set, and a recording method with which light fastness, water resistance, vivid color and color reproducibility, nozzle clogging resistance, and so forth can all be satisfied.
DISCLOSURE OF THE INVENTION
The stated object is achieved with the present invention as follows.
The magenta ink of the present invention comprises at least water, a water-soluble organic solvent, a first dye, and a second dye, the first dye has a structure expressed by the following General Formula I, the second dye is a dye having a structure expressed by the following General Formula II and/or one or more types of dye selected from among C.I. Acid Violet 9 and 30 and C.I. Acid Red 50, 52, and 289, and the weight ratio of first dye to second dye is 5:1 to 1:5.
M is H, Li, Na, K, ammonium, or an organic amine
R1 is H, Cl, or
X is an anilino group substituted with at least one SO
3
M
Y is OH, Cl, or a morpholino group
R2 is H, CH
3
, Cl, or SO
3
M
The dyes in the ink of the present invention may be water-soluble dyes.
It is preferable for the total amount of dye contained in the ink to be 0.5 to 5 wt % of the total ink weight.
The ink of the present invention may contain a glycol ether of a lower alkyl and/or an acetylene glycol-based nonionic surfactant.
The ink of the present invention may be such that the above-mentioned glycol ether of a lower alkyl includes at least one type of compound selected from the group consisting of diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether, and dipropylene glycol monobutyl ether.
The ink of the present invention may contain the glycol ether of a lower alkyl in an amount of 3 to 30 wt % of the total ink weight.
The ink of the present invention may contain the acetylene glycol-based nonionic surfactant in an amount of 0.1 to 3 wt % of the total ink weight.
The ink set of the present invention is an ink set composed of at least a dye, a water-soluble organic solvent, and water, wherein said ink set is composed of the magenta ink according to claim 1, a yellow ink containing a dye containing C.I. Direct Yellow 86 and C.I. Direct Yellow 132 in a weight ratio of from 1:3 to 3:1, or a dye containing C.I. Direct Yellow 86 and C.I. Direct Yellow 173 in a weight ratio of from 1:4 to 4:1, and a cyan ink containing C.I. Direct Blue 86 and/or C.I. Direct Blue 199.
In the ink set of the present invention, the respective dyes of the magenta ink, yellow ink, and cyan ink may be water-soluble dyes.
In the ink set of the present invention, it is preferable for the total amount of dye contained in the magenta ink to be 1 to 4 wt % of the total ink weight, the total amount of dye contained in the yellow ink to be 0.5 to 4 wt % of the total ink weight, and the total amount of dye contained in the cyan ink to be 1 to 4 wt % of the total ink weight.
The ink set of the present invention may contain a glycol ether of a lower alkyl and/or an acetylene glycol-based nonionic surfactant.
The ink set of the present invention may be such that the above-mentioned glycol ether of a lower alkyl includes at least one type of compound selected from the group consisting of diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether, and dipropylene glycol monobutyl ether.
The ink set of the present invention may contain the glycol ether of a lower alkyl in an amount of 3 to 30 wt % of the total ink weight.
The ink set of the present invention may contain the acetylene glycol-based nonionic surfactant in an amount of 0.1 to 3 wt % of the total ink weight.
The recording method of the present invention is an ink jet recording method in which printing is performed by discharging droplets of ink and causing them to adhere to a recording medium, wherein the above-mentioned ink is used as the ink.
Also, the recording met
Ito Jun
Kanaya Miharu
Ladas & Parry
Meier Stephen D.
Seiko Epson Corporation
Shah Manish
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