Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-01-30
2003-11-11
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S095000, C106S031130
Reexamination Certificate
active
06644800
ABSTRACT:
FIELD OF THE INVENTION
The present invention is drawn to inkjet images having improved visual properties. More particularly, the present invention is drawn to high quality images produced using small volume ink drops which display improved visual characteristics, such as lightfastness and optical density.
BACKGROUND OF THE INVENTION
In recent years, computer printer technology has evolved to a point where high-resolution images can be transferred to various media. Many of such images, are created using inkjet printers which place or “jet” ink drops onto a print surface. A number of reasons may account for the current popularity of inkjet printing, such as reduced noise, high speed recording capacity, and multi-color printing.
Various image characteristics determine overall image quality and may be manipulated in order to achieve desired results suitable to specific applications. Such characteristics include 1) edge acuity; 2) lightfastness; 3) optical density; 4) ink dry time; and 5) waterfastness, among others, and are determined by the specific ink formulations and printing equipment used.
In addition to image quality, printer equipment performance and reliability are major considerations in designing inkjet printer systems which are economically viable. Performance considerations such as consistent print accuracy, speed, durability, and long term reliability must be realized.
Though the above list of characteristics provides a worthy goal to achieve, there are difficulties associated with satisfying all of the above characteristics. Often, the inclusion of an ink component meant to satisfy one of the above characteristics can prevent another characteristic from being met. Thus, most commercial inks for use in inkjet printers represent a compromise in an attempt to achieve at least an adequate response in meeting all of the above listed requirements.
One particular printing application which has recently received much attention by inkjet printer manufactures is the printing of high quality images, such as photo images. In order to attain enhanced print quality and image quality as in a photograph, a variety of special print media have been developed to work with aqueous inks. However, such media is often cost prohibitive and is limited in its realistic use. Alternatively, images have been created using ink drops of relatively small volume in an effort to increase sharpness and achieve a photo print quality level of detail. Unfortunately, it has been found that images produced using small volume ink drops, such as those less than 5 pl, suffer from unusually low performance with respect to several visual characteristics, such as lightfastness and optical density. Particularly, the visual characteristic performance of small volume drops has been shown to be well below expected results based on comparatively larger ink volume drops.
Therefore, methods and systems which are capable of achieving photo quality print resolution while maximizing performance of various print quality characteristics, such as optical density and lightfastness are currently the focus of much research.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides an image on a substrate which includes, or is made using a plurality of small volume inkjet ink drops, said ink having an ink vehicle and a metalized dye having a heterocyclic nitrogen and a diazo bond wherein the heterocyclic nitrogen is chelated or complexed to a transition metal. In one aspect, the ink drop volume may be less than about 8 pl. In another aspect, the ink drop volume may be less than about 5 pl.
In one aspect, the metalized dyes of the inks used in the present invention may include a pyridine group bonded to a quinolinol group through an azo bond. In another aspect, the metalized dye may include a pyridine group bonded to a naphthalene group through an azo bond. In yet another aspect, the PAQ metalized dye may be in a dicarboxylate form.
A wide variety of metals, including transition metals may be used in the metalized dye of the present inks. In one aspect, the metal may be a transition metal selected from the group consisting of nickel, copper, iron, cobalt, chromium, iron, including di and tri-valent forms thereof, as well as other di and tri-valent metal ions, and combinations thereof. In one aspect, the metal may be nickel. In anther aspect, the metal may be copper.
The amount ligand and metal contained in each dye may vary according to the knowledge of one skilled in the art in order to achieve a desired result. In one aspect, the ligand and transition metal, may be present in a molar ratio of 2:1. In another aspect, the ligand to transition metal molar ratio may be 1:1.
The amount of metalized dye which is included in the inks used in the present invention may be an effective amount which is determined by one ordinarily skilled in the art to be sufficient to achieve a particularly desired result. However, in one aspect, the metalized dye may be present in an amount of from about 0.2% w/w to about 8% w/w of the ink. In another aspect, the metalized dye may be present in an amount of from about 1.1% w/w to about 6% w/w of the ink. In addition to the image recited herein, the present invention additionally encompasses a method for producing such an image. In one aspect, a method for creating an inkjet image may include the step of jetting small volume drops of an inkjet ink onto a substrate, wherein the ink has an ink vehicle and an effective amount of a metalized dye with at least one heterocyclic nitrogen ring and a diazo bond, and wherein the heterocyclic nitrogen is chelated or completed to a transition metal. Additional inks containing various dyes as disclosed herein may also be utilized in such a method.
There has thus been outlined, rather broadly, the more important features of the invention so that the detailed description thereof that follows may be better understood, and so that the present contribution to the art may be better appreciated. Other features of the present invention will become clearer from the following detailed description of the invention, taken with the accompanying claims, or may be learned by the practice of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
Before the present images and methods are disclosed and described, it is to be understood that the present invention is not limited to the particular process steps and materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.
In describing and claiming the present invention, the following terminology will be used.
The singular forms “a,” “an,” and, “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a dye” includes reference to one or more of such dyes, reference to “an ink” includes reference to one or more of such inks, and reference to “the color” includes reference to a mixture of one or more of such colors.
As used herein, “effective amount” refers to the minimal amount of a substance or agent, which is sufficient to achieve a desire effect. For example, an effective amount of an “ink vehicle” is the minimum amount required in order to create ink, which will meet the specified performance and characteristic standards. Additionally, the minimum amount of a “dye” would be the minimum amount, which can still achieve the specified performance and characteristic standards.
As used herein, “ink vehicle,” refers to the vehicle in which a dye is placed to form ink. Ink vehicles are well known in the art, and a wide variety of ink vehicles may be used to form ink compositions which are useful in the present invention. Such ink vehicles may include a mixture of a variety of different agents, including without limitation, surfactants, solvents, co-solvents, buffers, biocides, viscosity modifiers, surface-active agents, and wa
Hewlett--Packard Development Company, L.P.
Meier Stephen D.
Shah Manish
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