Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2000-06-22
2001-09-11
Koslow, C. Melissa (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031430, C106S031610, C106S031750
Reexamination Certificate
active
06287373
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to ink compositions and, more specifically, the present invention relates to inks with, for example, a melting point of between about 60° C. and about 150°C., and preferably between about 70 to about 90° C., especially useful for acoustic ink printing, processes and apparatuses, reference, for example, U.S. Pat. No. 5,121,141, U.S. Pat. No. 5,111,220, and U.S. Pat. No. 5,371,531, the disclosures of which are totally incorporated herein by reference, including especially acoustic ink processes as illustrated in a number of the above copending applications, such as an acoustic ink printer for printing images on a record medium. The inks of the present invention in embodiments can be considered (1) a phase change ink, that is, for example, an ink that changes from a liquid state to solid state in a suitable period of time, for example, from about 1 to about 100 milliseconds and preferably in less than about 10, such as from about 2 to about 7 milliseconds, and which inks contain a nonaqueous phase-change color spreading compound, or an additive, such as oxazoline compound that, for example, can fill the pores of a substrate, such as paper, and which compound has a melting point of, for example, lower than about 120° C. and preferably between about 60 to about 100° C., and with a low acoustic loss value of, for example, below about 100 dB/mm; (2) a nonaqueous crease improving thiourea compound or mixtures thereof with, for example, a boiling point of equal to about or higher than about 150° C. (Centigrade) and more specifically with a boiling point from about 150 to about 225° C., and a melting point of between about 25 to about 100° C., and preferably between about 60 to about 100° C., with low acoustic loss, which primarily enables a reduction or minimization of energy consumption, and which acoustic loss is below, or about equal to 60 dB/mm; (3) a gloss improving oxime compound or mixtures thereof; (4) a lightfastness component, such as a lightfastness UV absorber; (5) a lightfastness antioxidant; and (6) a colorant such as a dye, a pigment or mixtures thereof.
More specifically, the present invention is directed to phase-change acoustic ink compositions comprised of (1) a nonaqueous solid oxazoline compound with, for example, a melting point of lower than about 120° C. and preferably between about 60° C. and about 100° C., and possessing a low acoustic loss and which acoustic loss is, for example, below about 100 dB/mm, and preferably from about 25 to about 80 dB/mm; (2) a nonaqueous thiourea compound or mixtures thereof with, for example, a melting point of between about 25° C. to about 100° C., and preferably between about 60° C. to about 90° C., and with low acoustic loss and which acoustic loss is, for example, below about 60 dB/mm, and preferably between about 5 to about 40 dB/mm; (3) a gloss improving oxime compound or mixtures thereof with a boiling point of, for example, equal to about or higher than about 150° C. and lower than about 350° C., preferably between about 170° C. to about 220° C., and a melting point of, for example, between about 25° C. to about 90° C. and with a low acoustic loss and which acoustic loss is, for example, below or about equal to 60 dB/mm, and preferably in the range of between about 5 to about 40 dB/mm; (4) a lightfastness compound, such as a UV absorber; (5) an antioxidant; (6) a colorant, and wherein there can be generated with such inks excellent developed images on plain and coated papers with acceptable image permanence, excellent projection efficiency on transparencies without a post fusing step, and excellent crease resistance, and wherein the inks possess acceptable, and in embodiments superior lightfast, for example about 89 to about 100 percent and superior waterfast between, for example, about 94 to about 100 percent. Moreover, in embodiments of the present invention there is enabled the elimination, or minimization of undesirable paper curl since water need not be present. When water is not present in the inks, a dryer can be avoided thereby minimizing the cost of the acoustic ink jet apparatus and process.
PRIOR ART
In acoustic ink printing, the printhead produces approximately 2.2 picoliter droplets by an acoustic energy process. The ink under these conditions should display a melt viscosity of about 5 centipoise or less at the jetting temperature. Furthermore, once the ink is jetted onto the paper, the ink image should be of excellent crease property, and should be nonsmearing waterfast, of excellent transparency and excellent fix qualities. In selecting an ink for such applications, it is desirable that the vehicle display a low melt viscosity, such as from about 1 centipoise to about 25 centipoise in the acoustic head, while also displaying solid like properties after being jetted onto paper. Since the acoustic head can tolerate a temperature up to about 180° C., and preferably up to a temperature of from about 140° C. to about 160° C., the vehicle for the ink should preferably display liquid like properties such as a viscosity of 1 to about 10 centipoise at a temperature of from about 75° C. to about 165° C., and solidify or harden after jetting onto paper such that the ink displays a hardness value of from about 0.1 to about 0.5 millimeter utilizing a penetrometer according to the ASTM penetration method D1321.
Ink jet printing processes that employ inks that are solid at room temperature and liquid at elevated temperatures are known. For example, U.S. Pat. No. 4,490,731, the disclosure of which is totally incorporated herein by reference, discloses an apparatus for dispensing certain solid inks for printing on a substrate such as paper. The ink dye vehicle is chosen to have a melting point above room temperature so that the ink, which is melted in the apparatus, will not be subject to evaporation or spillage during periods of nonprinting. The vehicle selected possesses a low critical temperature to permit the use of the solid ink in a thermal ink jet printer. In thermal ink jet printing processes employing these phase-change inks, the solid ink is melted by a heater in the printing apparatus and utilized as a liquid in a manner similar to that of conventional thermal ink jet printing. Upon contact with the printing substrate, the molten ink solidifies rapidly, enabling the dye to remain on the surface instead of being carried into the paper by capillary action, thereby attempting to enable higher print density than is generally obtained with liquid inks. Phase-change ink jets are somewhat similar to thermal ink jets; however, a phase-change ink usually contains no solvent. Thus, rather than being liquid at room temperature, a phase-change ink is typically a solid with a wax-like consistency. These inks usually are heated, for example, to approximately 100° C. before the ink melts and converts to a liquid. With phase-change inks, a plurality of ink jet nozzles is provided in a printhead, and a piezoelectric vibrating element is located in each ink channel upstream from a nozzle so that the piezoelectric oscillations propel ink through the nozzle. After the phase-change ink is applied to the substrate, freezing on the substrate resolidifies the ink.
Each of these types of known ink jets, however, has a number of advantages and disadvantages. One advantage of thermal ink jets is their compact design for the integrated electronics section of the printhead. Thermal ink jets are disadvantageous in that the thermal ink has a tendency to soak into a plain paper medium. This blurs the print or thins out the print locally thereby adversely affecting print quality. Problems have been encountered with thermal ink jets in attempting to rid the ink of moisture fast is enough so that the ink does not soak into a plain paper medium. This is particularly true when printing with color. Therefore, usually when printing with thermal ink coated papers are used, which papers are more costly than plain paper.
One advantage of a phase-change ink is its ability to print on plain pap
Breton Marcel P.
Malhotra Shadi L.
Wong Raymond W.
Faison Veronica F.
Koslow C. Melissa
Palazzo E. O.
Xerox Corporation
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