Communications: directive radio wave systems and devices (e.g. – Return signal controls radar system – Receiver
Reexamination Certificate
1999-05-13
2002-04-09
Barlow, John (Department: 2853)
Communications: directive radio wave systems and devices (e.g.,
Return signal controls radar system
Receiver
Reexamination Certificate
active
06369750
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to an inkjet system (jettable solutions and receiver sheets) suitable for use in an inkjet recording process. It relates in particular to inkjet systems where recorded images can be observed by both reflected and transmitted light. Inkjet prints used at this present time have a need for improvement in physical and handling properties, particularly in water fastness, bleeding, humidity stability, light stability, reduced printhead clogging, as well as for improved image quality. In addition to the above deficiencies, the present dye systems used in inkjet have a restricted color space reproduction (i.e., are not able to produce the color gamut the human eye sees).
A preferred embodiment of this invention is therefore directed at an inkjet recording system with improved handling and performance characteristics. In particular, this system will give a recorded image that will overcome the shortcomings of the present systems by giving images that are resistant to rubbing smears, and bleeding remain intact upon contact with water, have good stability to humidity and light fading and will not cause clogging of the printhead; however, of utmost importance, the dye images produced will have improved color gamut and a photoreal appearance. All these benefits are obtained by the formation of an insoluble chromophore insitu (i.e., within the receiver matrix of this system). Furthermore, these are the same chromophore molecules used in present silver halide color photography, so color rendition is expected to be of photorealistic quality.
Inkjet printing systems generally are of two types: continuous stream and drop-on-demand. In continuous stream inkjet systems, ink is emitted in a continuous stream under pressure through an orifice or nozzle. The stream is perturbed, causing it to break up into droplets at a fixed distance from the orifice. At the breakup point, the droplets are charged in accordance with digital data signals and passed through an electric static field, which adjusts the trajectory of each droplet in order to direct it to a gutter for recirculation or a specific location on a recording medium. In drop-on-demand systems, a droplet is expelled from an orifice to a position on a recording medium in accordance with digital data signals. A droplet is not formed or expelled unless it is to be placed on the recording medium.
This invention is intended for use in both types of systems. The continuous stream system may allow for more options in the practice of this invention by allowing for the in-line premixing of two reactants such as color former and alkali before droplet formation. However in this configuration recycling of unused components would not be feasible.
2. Background Art
The following list describes some of the major requirements of an inkjet recording system in order to achieve commercial success:
1. Sufficient ink absorbing capacity and ink receptivity of the receiver layer to prevent the ink/pigment from streaking and running during printing, even under conditions where several droplets are deposited in a rapid sequence onto the same spot.
2. Fast drying of the layer surface after printing of the image leading to prints free from tackiness.
3. Excellent color rendition, no change of print hue with time.
4. The ability to have a high-gloss surface. Chromophores must not have a dull, flat look.
5. Transparencies must be clear, transparent, light scatter-free.
6. Resistance of the surface of the image to rubbing smear.
7. Excellent water fastness and minimal bleeding of the produced images.
8. Excellent light fastness of the printed image.
9. Excellent archival stability (especially photoreal).
10. Chromophores that have proper spectral quality for producing excellent color rendition
11. Chromophores that have proper spectral quality so go as to have color gamut space capabilities similar to what the human eye can see.
12. Inks that do not cause clogging of printheads.
At the present time no available system successfully addresses all these requirements. A number of approaches have been attempted to achieve the requirements of a good inkjet print. Water fastness has been addressed by a variety of techniques. Thus solutions to the problem have been proposed for by specific formulations of the inks or alternatively by specific modifications of the receiving layer.
One approach to improve water fastness has been the use of reactive dyes (U.S. Pat. No. 4,443,223 Kissling et al) and U.S. Pat. No. 5,230,733 (Pawlowski et al) and references cited therein. Although some improvement has been achieved by this approach, in general, under the conditions of practical printing, the environment is less than optimal and therefore do not achieve full reaction of these dyes with a given binder.
Another approach to both water fastness and light fastness has been inks based on colloidal dye dispersions and polymers in inks. U.S. Pat. No. 5,100,471 (Winnik et al), U.S. Pat. No. 5,017,644 (Fuller et al), U.S. Pat. No. 5,224,987 (Matrick et al) U.S. Pat. No. 4,246,154 (Yao et al). Inks based on colloidal dyes as well as hot melt inks although yielding images of good light and water fastness do in most cases lack brilliance, color gamut and are not totally transparent.
The use of cationic polymers in the receiver layer in conjunction with acidic inks to induce water fastness as described in U.S. Pat. No. 4,783,376 (Sakaki et al) and U.S. Pat. No. 4,575,465 (Viola) do in general give good water fastness. Although water fastness can be gained with this method, severe drawbacks in light stability, archival stability, and hue shifts accompany this simple benefit.
The introduction of inorganic pigments, filters, minerals, metal salts, and metal oxide have been proposed. U.S. Pat. No. 4,116,910 (Rudolphy et al) claims improved light stability.
The addition of pigments and polymers to improve water fastness and drying is described in U.S. Pat. No. 5,104,730 (Misuda et al) and U.S. Pat. No. 4,879,166 (Misuda et al). They describe the use of porous recording sheets where the porous layer is mainly pseudo boehmite. Although a number of advantages are claimed using these methods, most layers obtained by these methods become very brittle with age, are slightly opaque and have steep color rendition thus poor color space. Improvements incorporated into the receiving layer and jettable solution, to meet the prestated requirements of modern inkjet printing technology, are therefore the objectives of this invention.
SUMMARY OF THE INVENTION
Accordingly, the object of the present invention is to provide a jettable color forming solution and a receiving media containing a color developer, thus forming an insitu chromophore for use in inkjet recording.
Another objective is to obtain water fastness without affecting stability to light.
Another objective is to obtain insitu chromophore formation below the surface of the receiving layer.
Another objective is to obtain chromophore having good stability to humidity and light.
Another objective is to obtain chromophore having excellent color gamut.
Another objective is to obtain an inkjet recording media having an extended color rendition.
It is a further objective to provide clear, light scatter-free recorded images for use on a transparent base. Another objective of the invention is to obtain images of superior luster and sharpness.
This invention proposes to achieve the above objectives by providing an inkjet recording system where the jetting head or cartridge contains solutions of color couplers of the photographic type. These heads or cartridges would contain a cyan dye coupler, a magenta dye coupler, and a yellow dye coupler. The receiver sheet would contain a color developing agent. Under the proper conditions of pH and oxidation (O), an insitu chromophore material would be formed. The general reaction would be the following.
In all coupling reactions, an active methylene group and a p-phenylenediamine developer would be common. To the receiving layer or layers, a wide variety of ad
Barlow John
Brooke Michael S
Kodak Polychrome Graphics LLC
Salzman & Levy
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