Abstract: Pigments that have been at least partially treated to form surface-attached functional groups are combined with long chain amine oxides in an ink-jet ink to provide waterfastness. The ink-jet ink for ink-jet printing comprises: (a) a vehicle comprising (1) 0 to about 30 wt % of at least one organic solvent, and (2) 0 to about 30 wt % of at least one water-soluble surfactant, and (3) about 0.1 to 10 wt % of at least one zwitterionic surfactant; (b) about 1 to 20 wt % of at least one chemically-modified, water-soluble macromolecular chromophore comprising a pigment having functional groups covalently attached thereto; and (c) the balance water. The inks of the invention evidence increased waterfastness with the presence of the zwitterionic surfactant, yet other properties, such as decap, kogation, and edge acuity, are not adversely affected by the presence of the zwitterionic surfactant. Indeed, decap and edge acuity are improved by the presence of the zwitterionic surfactant.

Abstract: A smearfast, waterfast, and fast drying ink is provided, employing macromolecular chromophores (MMCs) and both ionic surfactants and zwitterionic, or amphoteric, surfactants, in which the ionic surfactant is of the opposite polarity of the MMC. Macromolecular chromophores are pigments whose surface has been treated to provide either anionic or cationic functional groups thereon. The zwitterionic surfactant gives rise to waterfastness, while the ionic surfactant gives rise to both smearfastness and fast drying.

Abstract: The ink of the invention comprises (a) a vehicle comprising (1) about 1 to 50 wt % of at least one organic solvent as humectants, and (2) about 0.01 to 20 wt % of at least one water-soluble surfactant or amphiphilic polymer (cationic, anionic, or non-ionic); (b) about 1 to 20 wt % of at least one partial chemically-modified, water-soluble colorant, the colorant having sufficient functional groups associated therewith to be substantially waterfast in deionized water while being sufficiently stable in the ink to avoid flocculation; and (c) the balance water. The use of a partial chemically-modified, water-soluble colorant (macromolecular chromophore) results in an ink that is both waterfast and non-flocculating.

Abstract: An ink-jet ink set comprises (a) a microemulsion-based black ink in which the colorant is a water-insoluble black pigment has been chemically modified to impart water solubility by addition of functional groups to form a macromolecular chromophore and (b) at least one non-black (cyan, yellow, or magenta) ink that is a typical aqueous dye-based ink with an agent that increases the ionic strength of the no-black ink and comprises either an inorganic salt or an organic acid; the organic acid is used to adjust the pH of the non-black ink to a value of less than 5. The non-black ink may alternatively comprise a water-insoluble non-black pigment that has also been chemically modified. The macromolecular chromophore-containing ink, or pigment-based ink, of the ink-jet ink set is a microemulsion that contains a substantially water-insoluble organic oil, an organic co-solvent, and water and, optionally, an amphiphile and a high molecular weight colloid.

Abstract: The ink of the invention comprises a vehicle and a colorant. The colorant is a water-insoluble macromolecule that has been chemically modified to be water soluble by addition of functional groups to the surface of the chromophores resulting in water soluble colorant particles. The resulting chromaphore is called a macromolecular chromophore (MMC). The performance of these MMCs is improved by substitution of (a) the normal counter-cations with substituted ammonium cations or (b) the normal counter-anions with any of a variety of organic and inorganic anions. The inks described herein demonstrate high edge acuity, high optical density, fast drying times, high waterfastness, and high smearfastness.

Abstract: An ink-jet ink for ink-jet printers is provided, comprising: (a) an aqueous-based vehicle; and (b) an anionic dye complexed with a polyamine in an amount sufficient to form a pH-insensitive, water-soluble, dye:polyamine complex that acts like a cationic dye. Further, a method of converting the anionic dye to the cationic dye for formulating the ink-jet ink having a desired pH is provided. The method comprises adding a sufficient amount of the polyamine to form the dye:polyamine complex. The dye:polyamine complex is a complex of the dye and the polyamine polymer, which is cationic. Consequently, this complex behaves as a cationic dye. These ink-jet inks show remarkable waterfastness on a variety of common office papers and are pH-insensitive and even in some cases, completely pH-independent. These inks are thus stable over a wide pH range.

Abstract: The ink of the invention comprises a vehicle and a colorant, with the vehicle comprising a microemulsion containing at least one substantially water-insoluble organic oil, at least one organic cosolvent, and water and, optionally, at least one amphiphile and at least one high molecular weight colloid. The colorant is a water-insoluble chromaphore that has been chemically modified to be water-soluble by addition of functional groups that impart water solubility. These functional groups are added to the surface of the chromaphore particles, resulting in water-soluble colorant particles. The inks described herein demonstrate high edge acuity, high optical density, fast drying times, reduced bleed, improved halo characteristics, high water fastness, and high smearfastness.

Abstract: A voltage detector including first and second current paths between a source voltage at a first level and current-limiting device joined to a second level of voltage, each path including an essentially-identical flash EEPROM memory device, one of the memory devices being programmed to have a lower threshold voltage than the other memory device; a circuit for providing a voltage to be measured to gate terminals of one of the memory devices and a percent of the voltage to be measured to the of one of the memory devices having the lower threshold voltage, and an output device connected to measure the current flowing through one of the current paths, the output device being arranged to conduct when current through the first path is greater than current through the second path and not to conduct when current through the first path is less than current through the second path.