Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-05-10
2004-03-30
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S096000, C106S031130, C106S031270
Reexamination Certificate
active
06712462
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an ink set that is suitable in particular for an ink jet recording method, and the ink jet recording method.
BACKGROUND ART
In an ink jet recording method, recording is carried out by discharging a recording liquid from minute nozzles provided in a recording head through the vibration of piezoelectric elements, the action of thermal energy or the like; the method has advantages such as quietness during recording, it being possible to obtain high-resolution images at high speed by using a high-density head, and running costs being low. The method is thus used in various recording fields such as printers for personal computers, video printers, and graphics printers.
In the case of forming color images using the ink jet recording method, inks of at least the three primary colors magenta, yellow and cyan are used, and recording of full-color images is carried out by controlling the discharged amount and dot density of each of the inks and thus carrying out subtractive color mixing. In recent years, a method has become common in which, to obtain high-resolution images, for the magenta and cyan inks, dark and light inks having a different density to one another are used to reduce the sensation of graininess, whereby finer images can be obtained. It is important that each of the inks itself has excellent color reproducibility, and it is also important that good color reproducibility can be realized when printing is carried out combining the dark and light magenta ink, yellow ink and dark and light cyan ink to form red, green, blue and black.
Furthermore, water-based inks are mainly used as ink jet inks from a safety perspective with regard to odor, fire prevention and so on, and various characteristics are demanded of these inks, for example values of physical properties such as the viscosity and surface tension being insuitable ranges, nozzle clogging properties and storage stability being excellent, recorded images with high density (high optical density, vivid tones) being provided, and light-fastness and water resistance being excellent.
Most of these properties are satisfied by using a water-based ink having water or a mixed liquid of water and a water-soluble organic solvent as a main solvent, but color reproducibility, vividness, light-fastness and so on are greatly influenced by the colorant used, and hence various dyes have been investigated from hitherto. In answer to the above demands, in Japanese Patent Application Laid-open No. H5-214259, Japanese Patent Application Laid-open No. H8-310116, Japanese Patent Application Laid-open No. H9-3380, and Japanese Patent Application Laid-open No. H11-199809, it has been disclosed that excellent color reproducibility and light-fastness can be obtained even for secondary colors and tertiary colors through ink sets that use specific dye sets.
Moreover, the properties of magenta ink are poor with regard to light-fastness in particular, and hence in Japanese Patent Application Laid-open No. S57-5769, WO 96/24636, Japanese Patent Application Laid-open No. S62-192474, Japanese Patent Application Laid-open No. S63-19288, Japanese Patent Application Laid-open No. H10-306221, Japanese Patent Application Laid-open No. H1-29730, Japanese Patent Application Laid-open No. H11-158429, Japanese Patent Application Laid-open No. 2001-19881 and so on, magenta dye inks having excellent tone, vividness and light-fastness have been disclosed. Moreover, in Japanese Patent Application Laid-open No. H2-127482, a recording method has been disclosed using dark and light inks in which the type of dye differs between the dark ink and the light ink.
However, with printed articles produced through conventional inkjet recording using such dyes, there is a problem that the printed article fades upon exposure to light. Fading is particularly marked with a single magenta ink color, and as a result there is a problem that fading is also great with secondary and tertiary colors such as red, blue and composite black. Furthermore, it is still not possible to provide color printing with high resolution and fastness as a color recording method, for example storage reliability with regard to clogging properties, discharge stability and so on, and toning and color reproducibility are insufficient.
Moreover, in the above-mentioned recording method, reliability with regard to ink clogging and so on, tone, vividness and light-fastness may not be at a sufficiently satisfactory level, and even if light-fastness is excellent with a single color, when mixing with another color light fading is promoted through interaction with the other color, and as a result it is still not possible to provide excellent images in the case of full color image formation.
It is thus an object of the present invention to resolve these problems. That is, it is an object of the present invention to provide an ink set according to which light-fastness is excellent, storage stability with regard to clogging, discharge stability and so on is good, and tone, color reproducibility and other properties are satisfied, and a recording method using this ink set.
Moreover, it is an object of the present invention to provide a magenta ink according to which reliability with regard to clogging and soon is high, coloration in the case of a single color is excellent, vividness and light-fastness are obtained, and color images can be obtained that have excellent vividness and light-fastness even in mixed color parts were mixing is carried out with an ink of another color.
DISCLOSURE OF THE INVENTION
The above-mentioned objects are attained through the following invention.
An ink set of the present invention is an ink set that comprises inks each of which contains at least a dye, a water-soluble organic solvent and water, and that comprises a combination of magenta ink that contains a dye having a structure shown in general formula (I) below, yellow ink, and cyan ink.
X: —COOM or —SO
3
M
Y: —H, —NH
2
or —O(CH
2
)
m
H
M: —H, —Li, —Na, —K, —NH
4
or —NH(CH
2
OH)
3
n=integer from 2 to 10
m=integer from 1 to 4
l=0 or 1
Moreover, in the ink set of the present invention, the yellow ink may be one that contains at least one dye selected from the group consisting of a dye containing C.I. Direct Yellow 86 and C.I. Direct Yellow 132 in a weight ratio of 1:3 to 3:1, and a dye containing C.I. Direct Yellow 86 and C.I. Direct Yellow 173 in a weight ratio of 1:4 to 4:1, and the cyan ink may be one that contains at least one dye selected from the group consisting of C.I. Direct Blue 86 and C.I. Direct Blue 199.
Moreover, the magenta ink in the ink set of the present invention may be dark and light magenta ink comprising dark magenta ink containing a dye having a structure shown in general formula (I) above, and light magenta ink containing a dye having a structure shown general formula (II) below.
(where X′ indicates an anilino group substituted with at least one SO
3
M;
Y′ indicates OH, Cl or a morpholino group;
M′ indicates H, Li, Na, K, ammonium, or an organic amine.)
Moreover, in the ink set of the present invention, the magenta ink may be dark and light magenta ink comprising dark magenta ink containing a dye having a structure shown in general formula (I) above, and light magenta ink containing a dye having a structure shown in general formula (II) above, the yellow ink may be one containing at least one dye selected from the group consisting of a dye containing C.I. Direct Yellow 86 and C.I. Direct Yellow 132 in a weight ratio of 1:3 to 3:1, and a dye containing C.I. Direct Yellow 86 and C.I. Direct Yellow 173 in a weight ratio of 1:4 to 4:1, and the cyan ink may be dark and light cyan ink containing at least one dye selected from the group consisting of C.I. Direct Blue 86 and C.I. Direct Blue 199.
Furthermore, the present invention also relates to an ink jet recording method of forming a color image using at least dark and light magenta ink, yellow ink, and dark and light cyan ink, the ink jet recording method using the above-mention
Ito Jun
Kanaya Miharu
Ladas & Parry
Meier Stephen D.
Seiko Epson Corporation
Shah Manish
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