Abstract: In a water base ink set for ink-jet recording, a pigment ink has a total ion concentration of lithium ion, potassium ion, and sodium ion of not less than 60 ppm and a total ion concentration of divalent or multivalent metal ion or ions of not more than 10 ppm, and a dye ink has a total ion concentration of lithium ion, potassium ion, and sodium ion of not more than 1,800 ppm and a total ion concentration of divalent or multivalent metal ion or ions of not more than 10 ppm, wherein the total ion concentration of lithium ion, potassium ion, and sodium ion of the dye ink is 3 to 25 times that of the pigment ink. Accordingly, the water base ink set in which the pigment ink and the dye ink can be reliably used in combination without complicating a maintenance system is provided.

Abstract: An ink set for ink-jet recording comprises a pigment ink and a dye ink containing a pigment and a dye as coloring agent, respectively. The pigment ink contains water, a water-soluble organic solvent, and a negatively charged pigment wherein potassium ion and sodium ion have a total ion concentration of not more than 200 ppm, and divalent or multivalent metal ion or ions have a total ion concentration of not more than 10 ppm. The dye ink contains water, a water-soluble organic solvent, and a dye associated with a counter ion of lithium ion wherein potassium ion and sodium ion have a total ion concentration of not more than 400 ppm, and divalent or multivalent metal ion or ions have a total ion concentration of not more than 10 ppm. In the ink set, the pigment and dye inks can be used in combination without complicating a maintenance system.

Abstract: A water base ink for ink-jet recording comprises water, self-dispersing type carbon black, an anionic surfactant, and a nonionic surfactant. The anionic surfactant is a surfactant represented by the formula (1) and/or a surfactant represented by the formula (2). The nonionic surfactant is a surfactant represented by the formula (3) or a mixture of a surfactant represented by the formula (4) and a surfactant represented by the formula (5). No ink discharge failure occurs, the long term stability is excellent, and it is possible to obtain a high quality image without any feathering.

Abstract: An ink for ink-jet recording is provided, in which an amount of water X (% by weight) in the ink and a saturation viscosity Y satisfy Y≦4.5e0.09X. The saturation viscosity Y is a viscosity (mPa·s) obtained when an ink residual liquid, which is obtained by evaporating volatile components of the ink until a change in weight of the ink is less than 0.05 g/day per 50 g of ink under a condition of a temperature of 60° C. and a humidity of 40%, is cooled to a temperature of 25° C. in an environment of a humidity of 40%. X satisfies 50≦X≦75. The ink exhibits satisfactory jetting stability when the ink is normally used. Further, the ink is easily restored to give a normal jetting state even after undergoing an abnormal condition, for example, when the ink is left to stand without any nozzle cap.

Abstract: A water base pigment ink for ink-jet recording contains a pigment, water, and at least one of polyethylene glycol and diglycerol. The ink is solidified into a solid matter when the water is evaporated. Further, the solid matter is redissolved in the unsolidified water base pigment ink for ink-jet recording. When the ink is used, then neither clog-up of a nozzle nor discharge failure is caused, no load is imposed by the solidified ink on the maintenance system such as the wiping equipment, and the sticking performance on the paper is satisfactory.

Abstract: A water base ink for ink-jet recording contains a dispersible coloring agent, a propylene glycol ether, and a surfactant composed of a random copolymer represented by the following general formula (1):

Abstract: An ink container including water-based ink for ink-jet recording and a package in which the water-based ink is accommodated, wherein the water-based ink includes an inert gas dissolved therein and an amount of oxygen dissolved in the water-based ink for ink-jet recording is less than 3 mL/L.

Abstract: An ink for ink-jet recording comprises a pigment, an anionic surfactant, and a cationic surfactant. The cationic surfactant interacts with the anionic surfactant which does not contribute to the dispersion of the pigment in the ink to avoid any excessive permeation of the anionic surfactant into paper. It is possible to obtain a sharp image in which the printing concentration is high and the feathering and the bleeding are scarcely caused.

Abstract: An ink set for ink-jet recording comprises a yellow ink, a magenta ink, and a cyan ink. Changes of colors &Dgr;EY, &Dgr;EM, &Dgr;EC of the yellow ink, the magenta ink, and the cyan ink satisfy the following relationship when the yellow ink, the magenta ink, and the cyan ink are deposited on regular paper, followed by being irradiated with light having a wavelength of 300 nm to 400 nm and an illuminance of 100 W/m2 for 30 hours by using a xenon lamp: |&Dgr;EY−&Dgr;EM|≦5, |&Dgr;EM−&Dgr;EC|≦5, |&Dgr;EC−&Dgr;EY|≦5. The ink set is excellent in color balance after the fading.

Abstract: A water base ink for ink-jet recording, which is usable for an ink-jet recording apparatus having an ink-jet head provided therein with an ink flow passage formed of nickel or nickel alloy, includes a coloring agent, water, and a water-soluble organic solvent. The ink is blended so that a current density, which is obtained within an electric potential range of −600 to +300 mV, is not more than 100 &mgr;A/cm2 when anodic polarization measurement is performed by using a reference electrode of silver/silver chloride, a counter electrode of platinum, and a working electrode of nickel or nickel alloy. The ink does not corrode any part for constituting the flow passage in the ink-jet head.

Abstract: A water base ink for ink-jet recording is provided, which is excellent in time-dependent stability of ink characteristics, which can be stably jetted over a long period of time, and which makes it possible to perform the high quality recording. The water base ink for ink-jet recording contains a self-dispersing type water-insoluble particulate coloring agent, a compound represented by the following formula (1), a surfactant having a nitrogen atom in a molecule, water, and a water-soluble organic solvent, wherein a surface tension is 30 to 50 mN/m, and a ratio of change of the surface tension after storage at 60° C.

Abstract: An ink for ink-recording is provided, which makes it possible to reduce color bleed while suppressing even when recording is performed on regular paper. The ink for ink-jet recording contains water, a coloring agent, a water-soluble organic solvent, and a compound represented by the following general formula (1): wherein R represents a alkyl group having a number of carbons of 8 to 18, and x+y is not more than 10. A surface tension of the ink is controlled to 31 to 35 mN/m, which can reduce color bleed and feathering.

Abstract: A printing ink composition is provided comprising water, a coloring agent and at least two types of polyalkylene glycol alkyl ethers each having at least one oxyalkylene in its polyoxyalkylene group, wherein at least one of the polyalkylene glycol alkyl ethers is polypropylene glycol n-butyl ether having three or more oxypropylenes in its molecule. This printing ink composition can inhibit color bleeding not only on a printing medium specifically designed for ink-jet printing but also on plain paper.

Abstract: An ink set for ink-jet recording is provided, in which the color bleed is reduced at adjoining portions of inks and the deposition of dye or the like in a color ink is not caused when a plurality of colors are recorded on regular paper. The ink set for ink-jet recording, which is composed of inks of a plurality of colors, includes at least one first ink and at least one second ink having the following compositions respectively. The first ink contains at least one anionicity-added pigment. The second ink contains at least one anionic dye and at least one ethanolamine hydrochloride selected from the group consisting of monoethanolamine hydrochloride, diethanolamine hydrochloride, triethanolamine hydrochloride, and thioethanolamine hydrochloride.

Abstract: A water base ink for ink-jet recording is provided, which makes it possible to secure a high recording quality with a sharp image area edge by avoiding any blurring even when recording is performed on regular paper and which has satisfactory purge restoration performance. Therefore, no bubble remains in an ink flow passage, and no discharge failure is caused. Further, the discharge operation never becomes unstable. In the water base ink for ink-jet recording, the surface tension is not less than 40 mN/m, and the amount of dissolved oxygen is not more than 4 mg/L.

Abstract: A water base ink for ink-jet recording is provided, which makes it possible to perform the discharge operation stably and highly accurately for a long period of time without deteriorating a metal, for example, due to corrosion and/or dissolution even when the ink makes contact with the metal composed of nickel or an alloy containing nickel for a long period of time. The water base ink for ink-jet recording is usable for an ink-jet recording apparatus provided with an ink-jet head having a metal member which is composed of nickel or the alloy containing nickel and which is disposed at least in an ink supply passage for supplying the ink to a discharge section. The water base ink for ink-jet recording contains potassium p-tert-butylbenzoate, a coloring agent which is dispersible or soluble in water, water, and a water-soluble organic solvent.

Abstract: An ink for ink-jet recording contains tripropylene glycol normal butyl ether or dipropylene glycol normal propyl ether, an acrylic polymer, a water-insoluble coloring agent, and water. The ink simultaneously satisfies the straight travel stability of ink droplets during the discharge with an ink-jet recording apparatus, the recovery performance upon introduction into a recording head of the ink-jet recording apparatus, the fixation performance of printed matters, and the drying performance after the printing.

Abstract: An ink for ink-jet recording is provided, which makes it possible to obtain vivid recorded matters by satisfying both of the prevention of the feathering and the prevention of the bleeding even when the recording is performed on regular paper. The ink for ink-jet recording contains a self-dispersing type microparticulate coloring agent, a surfactant, and water. When the surface tension is plotted in the vertical axis, and the concentration of the surfactant is plotted in the horizontal axis, then the correlation between the surface tension and the concentration of the surfactant can be represented by a correlation curve which has one inflection point and which has two local maximum points of curvature on both sides of the inflection point one by one. Further, the ink for ink-jet recording contains the surfactant at a concentration which is higher than a concentration corresponding to the local maximum point of the curvature on the low concentration side.

Abstract: A water base ink for ink-jet recording comprises water, a coloring agent, a water-soluble organic solvent, and a benzotriazole-based metal-inactivating agent and alkanolamine. When the ink is used in an ink-jet recording apparatus which has the metal member containing nickel or nickel alloy in an ink supply passage, nickel is eluted from the metal member in an amount of not more than 50 ppm. The ink makes it possible to perform stable jetting operation for a long term without causing any deterioration of metal members of a discharge head due to the metallic corrosion and the elution of nickel into the ink.

Abstract: A water base ink for ink-jet recording, which is usable for an ink-jet recording apparatus having an ink-jet head provided therein with an ink flow passage formed of nickel or nickel alloy, comprises a coloring agent, water, and a water-soluble organic solvent. The ink is blended so that a current density, which is obtained within an electric potential range of −600 to +300 mV, is not more than 100 &mgr;A/cm2 when anodic polarization measurement is performed by using a reference electrode of silver/silver chloride, a counter electrode of platinum, and a working electrode of nickel or nickel alloy. The ink does not corrode any part for constituting the flow passage in the ink-jet head.