Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
2000-03-09
2002-04-23
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Medium and processing means
C347S100000, C347S101000, C428S195100
Reexamination Certificate
active
06375320
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 employing a recording element containing coated particles.
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 contain colloidal particulates and have poorer image quality but exhibit superior dry times.
While a wide variety of different types of porous image-recording elements for use with ink jet printing are known, there are many unsolved problems in the art and many deficiencies in the known products which have severely limited their commercial usefulness. The challenge of making a porous image recording layer is to achieve a high gloss level without cracking, high color density, and a fast drying time.
U.S. Pat. No. 5,576,088 relates to an ink jet recording element wherein a gloss providing layer containing an inorganic filler and a latex is coated on top of an ink receiving layer. However, there is a problem with this element in that the drying time is slow and there is a tendency for the layer to exhibit cracks.
It is an object of this invention to provide an ink jet printing method using an ink jet recording element that has a fast ink dry time. It is another object of this invention to provide an ink jet printing method using an ink jet recording element that has good image quality.
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 ink-receptive elements comprising a substrate having thereon an image-receiving layer comprising an inorganic filler and coated particles comprising a polymeric hard core-polymeric soft shell latex, the Tg of the polymeric hard core material being greater than about 60° C., the Tg of the polymeric soft shell material being less than about 20° C., and the inorganic filler being present in the image-receiving layer in an amount of from about 50 to about 95% by weight;
C) loading the printer with an ink jet ink composition; and
D) printing on the ink-receptive element using the ink jet ink in response to the digital data signals.
The ink jet recording element obtained by the method of the invention provides a fast ink dry time and good image quality.
DETAILED DESCRIPTION OF THE INVENTION
The substrate used in the invention may be porous such as paper or non-porous such as resin-coated paper; synthetic paper, such as Teslin® or Tyvek®; an impregnated paper such as Duraform®; cellulose acetate or polyester films. The surface of the substrate may be treated in order to improve the adhesion of the image-receiving layer to the support. For example, the surface may be corona discharge treated prior to applying the image-receiving layer to the support. Alternatively, an under-coating or subbing layer, such as a layer formed from a halogenated phenol or a partially hydrolyzed vinyl chloride-vinyl acetate copolymer, can be applied to the surface of the support.
As described above, the image-receiving layer employed in the process of the invention contains an inorganic filler and a polymeric latex. Any inorganic filler may be used in the invention, such as metal oxides or hydroxides. In a preferred embodiment of the invention, the metal oxide is silica, alumina, zirconia or titania. In another preferred embodiment of the invention, the particle size of the filler is from about 5 nm to about 1000 nm.
The coated particles comprising a polymeric hard core-polymeric soft shell latex used in the process of the invention comprises polymeric particles having a core of material having a relatively high Tg which is coated with another polymer having a relatively low Tg. Core-shell latexes used in the invention may be prepared by emulsion polymerization are described in “Emulsion Polymerization and Emulsion Polymers”, edited by P. A. Lovell and M. S. El-Aassar, John Wiley and Sons, 1997.
The core material polymer used in the process of the invention has a Tg of at least about 60° C., preferably from about 60° C. to about 150° C. Examples of these polymers include poly(methylmethacrylate), poly(styrene), poly(p-methylstyrene), poly(t-butylacrylamide), poly(styrene-co-methylmethacrylate), poly(styrene-co-t-butylacrylamide), poly(methylmethacrylate-co-t-butylacrylamide), and homopolymers derived from p-cyanophenyl methacrylate, pentachlorophenyl acrylate, methacrylonitrile, isobornyl methacrylate, phenyl methacrylate, acrylonitrile, isobornyl acrylate, p-cyanophenyl acrylate, 2-chloroethyl acrylate, 2-chloroethyl methacrylate, 2-naphthyl acrylate, n-isopropyl acrylamide, 1-fluoromethyl methacrylate, isopropyl methacrylate, and 2-hydroxypropyl methacrylate. In a preferred embodiment of the invention, the core polymer is poly(methylmethacrylate), poly(styrene), poly(p-methylstyrene), poly(t-butylacrylamide) or poly(styrene-co-methylmethacrylate).
The shell material polymer used in the element employed in the process of the invention has a Tg of about 20° C. or lower, preferably from about −50° C. to about 20° C. Examples of these soft shell polymers which may be used in the invention include homo- and copolymers derived from the following monomers: n-butyl acrylate, n-ethylacrylate, 2-ethylhexylacrylate, methoxyethylacrylate, methoxyethoxy-ethylacrylate, ethoxyethylacrylate, ethoxyethoxyethylacrylate, 2-ethylhexyl-methacrylate, n-pro
Chen Tien-teh
Chu Lixin
Barlow John
Cole Harold E.
Eastman Kodak Company
Shah Manish S.
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