Patent Application
20080081203
a and 1b illustrate representative embodiments of a substrate embodying features of the present invention.
a and 3b illustrate an embodiment of a print medium embodying features of the present invention.
The present invention is directed to printable articles comprising a medium (“substrate”) usable in inkjet printing apparatus (either or both piezoelectric and thermal inkjet, or other forms of inkjet printing). In one embodiment, the substrate comprises a base medium and an image enhancing material which is present either or both as a layer disposed adjacent to the base medium and within the material from which the base medium is formed. According to an embodiment, the base medium is, but not limited to, porous media including cotton bond, canvas, rice paper; and fiberglass. In an embodiment, the substrate is formed from woven material formed from fibrous materials, such as cellulose or glass containing fibers, examples of which include canvas material and fiberglass. As used herein, woven refers to a medium formed, at least in part, from interlaced strands or fibers.
According to an embodiment, the substrate includes a backing layer disposed adjacent the base medium and opposite the at least one image enhancing layer (or the printing side). In an embodiment, the backing layer is further layered with a release liner, such as a silicone coated release liner.
In an embodiment, the substrate is a “printed substrate” that is at least partially covered with an image formed by way of for example inkjet ink. The present invention is further directed to methods of manufacture of the substrate, as well as “inkjet printing systems,” including either or both printer and “inkjet pens,” for use with, or with which, such substrate is usable. The substrates of the present invention provide for enhanced print performance including image quality and durability (e.g., water-fastness).
The substrate may be used to print images (i.e., creating “printed substrate”) thereon using commercially available inkjet printers from a number of manufacturers. The inkjet printers include, by way of example, piezo and thermal inkjet printers, both desk top and large format. Examples include Deskjet®, Business Inkjet, Photosmart® Inkjet, and Designjet® printers, all manufactured by Hewlett-Packard Company of Delaware.
As used in this specification and in the appended claims, the following terms have the following meanings:
Any of the terms “substrate,” “print substrate,” “print media,” “print medium,” and base material is meant to encompass a substrate based on cellulosic fibers (e.g., canvas), synthetic fibers (e.g., polyamides, polyesters, polyethylene, and polyacrylic fibers), inorganic fibers (e.g., asbestos, ceramic, and glass fibers such as fiberglass), extruded plastics (e.g. vinyl, polyester and polyvinylchloride (PVC)), and any combination of thereof. The substrate may be of any dimension (e.g., size or thickness) or form (e.g., pulp, wet paper, dry paper, etc.). The substrate is preferably in the form of a flat sheet, or roll structure, which structure may be of variable dimensions (e.g., size and thickness). The term “sheet” or “flat structure” is not meant to be limiting as to dimension, roughness, or configuration of the substrate, but rather is meant to refer to a product suitable for printing. The term ‘layer’ as used herein includes either or both one or more thicknesses, courses, or folds laid or lying over or under another (“Composite Structure”); and a material impregnating another.
As used herein, “image quality” refers to the fullness, intensity, clarity, and overall image characteristics of an inkjet ink after application to the print medium (thus forming the printed substrate). These visual effects are generally a measure of the concentration of ink at a given point on the printed substrate, the presence or absence of unwanted bleeding of one color into another.
The terms “waterfast” and “dripfast” are used herein to describe a form of water resistance which is normally used to refer to the nature of the ink composition after drying on the substrate. In general, waterfast and dripfast mean that the dried composition is substantially insoluble in water, such that upon contact with water, the dried ink retains at least about 70%, preferably at least about 85%, and more preferably at least about 95%, of optical density. In particular, waterfast generally refers to the waterfastness characteristics of the printed medium after full immersion of the medium in water, while dripfast refers to its performance after droplets of water have been applied, in a drip fashion, onto the media.
As used herein, “porosity” refers to the amount of ink that the coating can absorb during the printing process. In general, inkjet receiving layers consist of swellable or porous coating technologies. Porosity has a particular effect on image quality when porous coating technology is applied into the inkjet receiving layer. For example, a high porosity coating can create good image quality in canvas media, however, the cracking of high porosity coatings is problematic when stretching the printed canvas around a frame. On the other hand, a low porosity coating improves cracking, but yields poor image quality due to the bleed that occurs during printing. In the present invention, a metallic salt is applied on the surface of the inkjet receiving layer with low porosity coating, yielding excellent image quality while maintaining good cracking performance. Porosity may be measured using a pore size analyzer from Autosorb-1 made by Quantachrome, Boynton Beach, Fla. (USA).
As used herein, the term “printable article” refers to article comprising the substrate or a product comprising the substrate (as for example described below as a surfboard product).
In an embodiment, the image enhancing material includes at least one cationic compound including but not limited to metallic salts such as inorganic cationic species and/or salts thereof.
Suitable examples of metallic salts (e.g., reference element 18 in
Exemplary embodiments of the metallic salt includes, but is not limited to, sodium chloride, aluminum chloride, aluminum bromide, aluminum sulfate, aluminum nitrate, aluminum acetate, barium chloride, barium bromide, barium iodide, barium nitrate, calcium chloride, calcium bromide, calcium iodide, calcium nitrate, calcium acetate, copper chloride, copper bromide, copper sulfate, copper nitrate, copper acetate, iron chloride, iron bromide, iron iodide, iron sulfate, iron nitrate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium nitrate, magnesium acetate, nickel chloride, nickel bromide, nickel sulfate, nickel nitrate, nickel acetate, zinc chloride, zinc bromide, zinc sulfate, zinc nitrate, zinc acetate; or combinations thereof. In an embodiment, the metallic salt includes sodium chloride, aluminum chloride, calcium chloride, calcium nitrate, magnesium chloride; or combinations thereof.
The image enhancing material is present in an amount yielding a coating weight of about 0.01 to about 10 g/m2, often from about 0.1 to about 5 mg/m2, and usually from about 1 to about 5 g/m2.
The treatment of the base medium may result in the presence of the image enhancing material either or both as an image enhancing layer disposed adjacent the base medium and within the porous or fibrous material of the base medium when a porous material is used (e.g., cotton, canvas, fiberglass).
In an embodiment, a base medium with an image enhancing layer is printed and then further coated with a resin or lacquer, atop the image enhancing layer. In an embodiment, the resin coating is selected to be compatible with the base medium and other components of the substrate, such that upon its disposing, may include subsequent curing thereof, such that it encapsulates the printed article and is, at least substantially, transparent. Examples of suitable resins include polyurethanes, polyesters, epoxies, and combinations thereof. Examples of typical base medium include fiberglass, rice paper, cloth, canvas, or cotton bond paper.
The substrate may include other components such as, but not limited to, binders, starch, optical brighteners, inorganic or organic filler, sizing agents, anionic reagents, and combinations thereof.
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In an embodiment, features of which are shown in
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In an effort to further assess the improvements obtained as a result of the practice of features of the present invention, different examples were prepared.
In one series of examples, different types of base medium were treated with the image enhancing material 18, such as CaCl2. In one example, a 0.1% by weight of CaCl2 aqueous solution was spray coated on the base media to yield a coating weight of about 0.1 to about 0.5 g/m2.
The samples were evaluated for general image quality, “IQ,” by visually evaluating the samples for attributes such as color density and unwanted bleed as well as measured quantitatively for bleed performance. The results are represented in TABLE I below:
In another series of experiments, a treated fiberglass-based surfboard was prepared to yield the embodiment described in reference to
While particular forms of the invention have been illustrated and described herein, it will be apparent that various modifications and improvements can be made to the invention. Moreover, individual features of embodiments of the invention may be shown in some drawings and not in others, but those skilled in the art will recognize that individual features of one embodiment of the invention can be combined with any or all the features of another embodiment. Accordingly, it is not intended that the invention be limited to the specific embodiments illustrated. It is intended that this invention to be defined by the scope of the appended claims as broadly as the prior art will permit.
