Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
2000-02-28
2002-09-10
Hess, Bruce H. (Department: 1774)
Incremental printing of symbolic information
Ink jet
Medium and processing means
C347S106000, C428S195100
Reexamination Certificate
active
06447114
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an ink jet printing method. More particularly, this invention relates to an ink jet printing method that uses a recording element containing pigments.
BACKGROUND OF THE INVENTION
In a typical ink jet recording or printing system, ink droplets are ejected from a nozzle at high speed towards a recording element or medium to produce an image on the medium. The ink droplets, or recording liquid, generally comprise a recording agent, such as a dye or pigment, and a large amount of solvent. The solvent, or carrier liquid, typically is made up of water, an organic material such as a monohydric alcohol, a polyhydric alcohol or mixtures thereof.
An ink jet recording element typically comprises a support having on at least one surface thereof an ink-receiving or image-forming layer, and includes those intended for reflection viewing, which have an opaque support, and those intended for viewing by transmitted light, which have a transparent support.
While a wide variety of different types of image-recording elements for use with ink jet devices have been proposed heretofore, there are many unsolved problems in the art and many deficiencies in the known products which have limited their commercial usefulness.
It is well known that in order to achieve and maintain photographic-quality images on such an image-recording element, an ink jet recording element must:
Be readily wetted so there is no puddling, i.e., coalescence of adjacent ink dots, which leads to non-uniform density
Exhibit no image bleeding
Exhibit the ability to absorb high concentrations of ink and dry quickly to avoid elements blocking together when stacked against subsequent prints or other surfaces
Exhibit no discontinuities or defects due to interactions between the support and/or layer(s), such as cracking, repellencies, comb lines and the like
Not allow unabsorbed dyes to aggregate at the free surface causing dye crystallization, which results in bloom or bronzing effects in the imaged areas
Have an optimized image fastness to avoid fade from contact with water or radiation by daylight, tungsten light, or fluorescent light
An ink jet recording element that simultaneously provides an almost instantaneous ink dry time and good image quality is desirable. However, given the wide range of ink compositions and ink volumes that a recording element needs to accommodate, these requirements of ink jet recording media are difficult to achieve simultaneously.
Ink jet recording elements are known that employ porous or non-porous single layer or multilayer coatings that act as suitable image receiving layers on one or both sides of a porous or non-porous support. Recording elements that use non-porous coatings typically have good image quality but exhibit poor ink dry time. Recording elements that use porous coatings typically have poorer image quality but exhibit superior dry times.
The above-referred to U.S. application Ser. No.09/451,786 by Sadasivan et al. relates to a porous ink jet recording element comprising a substrate having thereon an image-receiving layer comprising an inorganic, anionic pigment, an organic, anionic binder and an organic, cationic mordant. While that ink jet recording element provides good image quality and last ink dry times, it would be desirable to improve the image quality. as measured by optical density.
U.S. Pat. No. 5,104,730 relates to an ink jet recording sheet comprising a substrate and porous ink absorbent layers formed upon the substrate, wherein the bottom layer is pseudo-boehmite and a binder and the top layer is a fine silica powder. However, there is a problem with this element in that the top layer has to be peeled-off after printing which reduces the image optical density.
It is an object of this invention to provide an ink jet printing method that uses a recording element that has a fast ink dry time. It is another object of this invention to provide an ink jet printing method that uses an ink jet recording element that has good image quality. It is another object of the invention to provide an ink jet printing method that uses an ink jet recording element that has improved gloss.
SUMMARY OF THE INVENTION
These and other objects are achieved in accordance with the invention which comprises an ink jet printing method comprising the steps of:
a) providing an ink jet printer that is responsive to digital data signals;
b) loading the printer with an inkjet recording element comprising a substrate having thereon an image-receiving layer comprising an inorganic, anionic pigment, an organic, anionic binder and an organic, cationic mordant, and a porous overcoat layer located over the image-receiving layer, the porous overcoat layer comprising an inorganic pigment and an organic, anionic, binder, wherein the refractive index of the inorganic pigment in the overcoat layer is at least 0.05 refractive index units less than the refractive index of the inorganic, anionic pigment in the image-receiving layer;
c) loading the printer with an ink jet ink composition; and
d) printing on the recording element using the ink jet ink in response to the digital data signals.
The ink jet recording element produced by the method of the invention provides good image quality, fast ink dry times and improved gloss.
DETAILED DESCRIPTION OF THE INVENTION
The inorganic, anionic pigment in the image-receiving layer useful in the invention may be a kaolin clay, a calcined clay, calcium carbonate, titanium dioxide, talc or a silicate. In a preferred embodiment of the invention, the inorganic, anionic pigment used is a kaolin clay sold under the trade name Hydraglos® 92 (J.M. Huber Company). The amount of inorganic, anionic pigment used may range from about 50% to about 95% of the image-receiving layer.
The organic, anionic binder of either layer useful in the invention may be a styrene acrylic latex; a styrene butadiene latex, such as Styronal ® BN 4606X (BASF Corp.); a poly(vinyl alcohol); a poly(vinyl acetate), such as Vinac ® 884 (Air Products Inc.). a cellulosic or a polyurethane binder. In a preferred embodiment of the invention, a commercially-available styrene acrylic latex such as Acronal ® S-728 (BASF Corp.) is used in the image-receiving layer. In another preferred embodiment of the invention, a commercially-available poly(vinyl alcohol) such as Airvol ® 21-205 (Air Products Inc.) is used in the overcoat layer.
The organic, anionic binder may be used in an amount of from about 5% to about 20% of the image-receiving layer or overcoat layer. In general, good results are obtained when the ratio of pigment to binder is from about 5:1 to about 8:1.
The organic, cationic mordant useful in the invention may be a polymer latex dispersion or a water-soluble polymer solution. Examples of mordants useful in the invention are disclosed in U. S. Pat. No. 5,474,843, the disclosure of which is hereby incorporated by reference. Other useful mordants include cationic urethane dispersions sold under the trade name Witcobond® W-213 and Witcobond ® W-215 (Witco Corporation).
In a preferred embodiment of the invention, the organic, cationic mordant is:
M1: poly(N-vinyl benzyl-N-benzyl-N,N-dimethyl ammonium chloride-co-styrene-co-divinyl benzene),
M2: poly(N-vinylbenzyl-N,N,N-trimethylammonium chloride-co-ethylene glycol dimethacrylate), or
M3: poly(N-vinylbenzyl-N,N,N-trimethylammonium chloride-co-divinyl benzene).
In general, good results have been obtained when the mordant polymer is present in an amount of from about 1% to about 75% by weight of the image-receiving layer, preferably from about 10% to about 20%.
Smaller quantities of up to about 10% of other binders may also be added to the image-receiving layer such as poly(vinyl pyrrolidone) sold as Luviskol ® VA 64W (BASF Corp.) or poly(vinyl pyrrolidone-co-vinyl acetate) sold as Luviquat ® PQ11PN (BASF Corp.). In addition to the above major components, other additives such as pH-modifiers like nitric acid, cross-linkers, rheology modifiers, surfactants, UV-absorbers, biocides, lubricants, dyes, optical brighteners etc. may b
Janssen John W.
Sadasivan Sridhar
Sunderrajan Suresh
Whittaker Patrick J.
Cole Harold E.
Eastman Kodak Company
Grendzynski Michael E
Hess Bruce H.
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