Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2002-07-02
2004-03-30
Shosho, Callie (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C347S100000, C347S105000
Reexamination Certificate
active
06713531
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a pigmented ink used for ink jet printing and an ink jet recording method, specifically, to a water-based pigmented ink used for ink jet printing and an ink jet recording method by the use thereof; and in particular, to a water-based pigmented ink used for ink jet printing superior in discharge stability, thereby leading to formation of images exhibiting high glossiness, and superior water-proof and abrasion resistance on a glossy medium used for ink jet printing, and an ink jet recording method by the use thereof.
BACKGROUND OF THE INVENTION
Ink jet recording methods enable high definition recording by using a relative simple apparatus, having made rapid development in various field. There are also manufactured printers employing an ink jet recording system for use in various field and the inks used therein include diverse kinds in accordance with the usage thereof.
As an ink used for images which required resistance to photofading, for example, pigment inks using a pigment superior in light fastness as a colorant are used. In cases when the image printed on media having a high surface glossiness such as glossy paper or glossy films used for ink jet recording, pigment inks tend to be inferior in adhesion to the media, compared to dye inks, often leading to insufficient water resistance or insufficient abrasion resistance.
Swell-type media, in which water-soluble binder is coated, or void-type media, in which the fine void structure is formed of a filler and binder are preferably employed to display such high glossiness. In the void type media, the size of pores formed on the media surface are designed to be smaller to display such high glossiness, compared to plain paper or coated paper and the size of pores formed on the media surface is generally smaller than the mean size of the pigment particles. Almost material to be put into the interior is liquid contained in the ink. Therefore, in cases where being recorded with a pigment ink on the media having a high surface glossiness, it is contemplated that the main factor with regard to insufficient resistance to abrasion is that most of the pigment particles are fixed on the media surface.
To enhance the water resistance of pigment inks, for examples, the use of oil-based inks using oil-soluble solvents was proposed. The use of oil-based inks, though often enhancing advantageously water resistance of recorded images, produces problems such as odor or safety concerns of the solvent and necessity of media suitable for the oil-based inks. Further, oil-based inks still have a problem regarding abrasion resistance.
There was also proposed to improve water resistance using so-called solid jet ink in which solid wax is discharged through a solution. The solid jet ink has less of a problem in its odor and safety concerns, or selection of suitable media, compared to oil-based pigment inks, but produces problems that an apparatus tends to be large due to the complex internal mechanism of the printer and a large amount of energy is required to dissolve the ink. Further, similarly to the oil-based pigment inks, the solid jet inks has a problem in abrasion resistance.
There have been proposed various techniques for making improvements in water resistance and abrasion resistance of water base inks. JP-A 56-84992, 59-20696 and 59-155089 (hereinafter, the term, JP-A means unexamined and published Japanese Patent Application) describe incorporation of a cationic compound into a recording layer of the recording media to fix an anionic dye contained in a water ink to improve water resistance. However, there were still problems such that the improvement of water resistance of a pigment ink fixed on the media surface was not at a sufficient level in this technique and recording media exclusively used therefor were needed.
JP-A 63-299971, 64-69381, 6-99576, 8-20159 and 8-218498 describe a technique for improving water resistance, in which a colorless ink containing a cationic compound is allowed to combine with an anionic colorant-containing ink on recording images. In this technique, however, there were problems that one or more series of nozzles exclusively used for discharging the colorless ink are needed and plural cleaning mechanisms of the head were needed, often making the apparatus excessively large and complex.
JP-A 8-311383 describes addition of a pigment having a mean particle size of not more than 0.3 &mgr;m in an amount of 1 to 10% by weight and a neutralization product of an alkali-soluble resin having a weight-averaged molecular weight of not more than 20,000 in an amount of 3 or more times the pigment into a water ink, thereby improving water resistance and abrasion resistance of printed images. However, there were still problems in this technique that the increased content of the resin caused an increase in viscosity of the entire ink, necessitating high energy in its discharge or often making it difficult to stably discharge it.
JP-B 60-32663 (hereinafter, the term, JP-B means published Japanese Patent) and JP-A 4-18462 describe a technique for improving water resistance and abrasion resistance, in which a latex is incorporated in the ink. This technique, however, resulted in problems in the media having high glossiness that incorporation of a latex in the ink in an amount sufficient to effectuate water resistance and abrasion resistance tended to cause deterioration in storage stability of the ink or occurrence of clogging in the nozzle section of the head or in the filter section.
As described in the foregoing, methods conventionally known in the art were proved to be difficult to make improvements in water resistance and abrasion resistance of pigment inks, and there were also problems that deterioration in ink storage stability, clogging of the nozzle and deterioration in discharge stability tend to occur. Further, in cases when the media to be recorded are glossy paper or glossy film used for ink jet printing, both of which exhibit high surface glossiness, pigment are fixed on the media surface, making it more difficult to improve water resistance or abrasion resistance, as compared to plain paper or coated paper in which pigments are easily fixed in the interior of the media.
In cases where recorded on media exhibiting high surface glossiness, not only water resistance and abrasion resistance, but also texture of the images, specifically exhibiting high glossiness and no difference in glossiness from the non-printed portions (white background) are required. As described above, when recorded with a pigment ink on glossy paper or film, most of the pigment is fixed on the surface of the media so that texture is liable to be deteriorated, compared to dye inks. Further, there arose a problem that the technique applied to the ink to enhance water resistance and abrasion resistance readily induced deterioration in texture. Furthermore, in cases where printing with the pigment ink on transparent media, light transmittance in image areas was deteriorated due to optical scattering, producing problems that when images are projected on a screen using an overhead projector, images with deteriorated chroma were easily formed.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a water base pigment ink used for inkjet printing, thereby leading to formation of images exhibiting high glossiness, and superior water resistance and abrasion resistance on glossy media used for ink jet printing, and an ink jet recording method by the use thereof.
Further, it is an object of the invention to provide a water-based pigmented ink used for inkjet printing, thereby leading to formation of images exhibiting high transparency, and superior water-proof and abrasion resistance on transparent media used for ink jet printing, and an ink jet recording method by the use thereof.
The above objects can be accomplished by the following constitution:
(1) A water-based pigmented ink for use in ink jet printing comprising a pigment and a latex, wherein the average particle
Frishauf Holtz Goodman & Chick P.C.
Konica Corporation
Shosho Callie
LandOfFree
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