Abstract: An ink for ink-jet recording of the present invention includes water and a pigment. A total amount of free monovalent metal is not more than 300 ppm in the ink, and a total amount of free divalent or polyvalent metal is not more than 5 ppm in the ink. The ink may further comprise an antiseptic/fungicidal agent. The ink is excellent in dispersion stability of the pigment. The ink is stably discharged from a head over a long period without causing any clog-up at an ink flow passage and a nozzle of the head of a recording apparatus.

Abstract: An ink for ink-jet recording of the present invention includes a dispersion of a pigment, and an ink solvent containing a water-soluble organic solvent and glycol ether. The ink is prepared such that an Rf value, which represents a rate of flow of the pigment obtained when the pigment dispersion is developed with the ink solvent by means of paper chromatography, is not more than 0.5. The ink has a fast permeation speed, and hence the feathering and the bleeding are avoided.

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.

Abstract: An ink set for ink-jet recording includes two or more inks each of which contains water, a coloring agent, and a water-soluble organic solvent. The ink set is prepared so that a ratio (Vmin/Vmax) between a maximum permeation velocity Vmax of the ink and a minimum permeation velocity Vmin of the ink is not less than 0.6 when the respective inks are developed by means of paper chromatography on a certain paper. It is possible to suppress the bleeding of a formed image.

Abstract: An ink for ink-jet recording of the present invention comprises a dispersion of a pigment, and an ink solvent containing a water-soluble organic solvent and glycol ether. The ink is prepared such that an Rf value, which represents a rate of flow of the pigment obtained when the pigment dispersion is developed with the ink solvent by means of paper chromatography, is not more than 0.5. The ink has a fast permeation speed, and hence the feathering and the bleeding are avoided.

Abstract: An ink for ink-jet recording comprises a water-soluble solvent, a pigment, and a compound represented by the following general formula (1): 1

Abstract: An ink for ink-jet recording of the present invention comprises water and a pigment. A total amount of free monovalent metal is not more than 300 ppm in the ink, and a total amount of free divalent or polyvalent metal is not more than 5 ppm in the ink. The ink may further comprise an antiseptic/fungicidal agent. The ink is excellent in dispersion stability of the pigment. The ink is stably discharged from a head over a long period without causing any clog-up at an ink flow passage and a nozzle of the head of a recording apparatus.

Abstract: An X-ray image reader including a plurality of read heads and a scan drive device for scanning an X-ray image-storing member by moving the read heads is disclosed. The X-ray image reader has a multi head mode in which a read processing of an X-ray image held on the X-ray image storing member is performed by using at least two of the read heads, and a single head mode in which a read processing of an X-ray image held on the X-ray image storing member is performed by using only one of the read heads. The multi head mode is selected when a high-speed measurement is requested and the single head mode is selected when precise measurement is requested.

Abstract: An inventive ink comprises a water-soluble dye or a pigment as a coloring agent, 5 to 15% by weight of polyvalent alcohol monoalkyl ether selected from the group consisting of tetraethylene glycol monoalkyl ethers and pentaethylene glycol monoalkyl ethers, 5 to 50% by weight of polyvalent alcohol, and pure water. When recording is performed in accordance with the ink-jet recording system by using the inventive ink, an excellent result is obtained from any viewpoint concerning, for example, the recording characteristic, the fixation to an objective recording material, the quick drying characteristic, the printing quality characteristic, and the low odor characteristic. The inventive ink is useful as an ink to be used for ink-jet recording apparatuses based on various recording systems, making it possible to obtain an excellent recording result.

Abstract: A recording ink composition comprises pure water, a water-soluble dye, a polyvalent alcohol, and phosphoric acid. When iron is contained as an impurity in the recording ink composition, the iron and phosphoric acid form a ferric (III) phosphato complex ion represented by ?Fe(HP0.sub.4)(H.sub.2 O)!.sup.+. Owing to the formation of the complex ion, the recording ink composition is prevented from discoloration which would be otherwise caused by iron ion. Further, the recording ink composition is prevented from formation and deposition of iron compounds. Therefore, the obtained ink has an excellent color tone, and the ink avoids blocking at a nozzle of a printing head or the like of an ink-jet printer.

Abstract: A water-based magenta ink composition comprises an aqueous medium and a magenta dye dissolved therein, which employs Color Index Number Acid Red 52 as the magenta dye and contains 5 to 15% by weight of a polyhydric alcohol alkyl ether having a vapor pressure of 0.1 mmHg or below at 20.degree. C.

Abstract: A water-based magenta ink composition comprising an aqueous medium, a magenta dye dissolved therein and a pH adjuster, where, as the magenta dye, Color Index Number Acid Red 52 is used; as the pH adjuster, a basic organic compound is used; and the pH of the water-based magenta composition is adjusted to a value within the range of from 8 to 10.

Abstract: A water-based ink composition having an aqueous medium, a dye dissolved therein, and a pH adjuster. The pH adjuster may be any one of the following (1) to (4):(1) triethanolamine and triethanolamine hydrochloride;(2) triethanolamine and hydrochloric acid;(3) tris (hydroxymethyl) aminomethane and tris (hydroxymethyl) aminomethane hydrochloride; and(4) tris (hydroxymethyl) aminomethane and hydrochloric acid; and is used to adjust the pH of the water-based ink composition to a value within the range of from 8 to 10.

Abstract: An ink composition comprises a dye, water, at least one of a polyhydric alcohol and an alkyl ether of a polyhydric alcohol, and an organic weakly basic compound, and has a pH range of 8 to 10.

Abstract: An ink composition comprising a dye or a pigment, dissolved or dispersed in an aqueous medium, and having nitrates and nitrites in a total content less than 5 ppm.

Abstract: A water-based recording magenta ink composition comprises a magenta dye dissolved in a mixed solvent of water and a water-soluble organic solvent. The magenta dye comprises Color Index Number Acid Red 52 and the water-soluble organic solvent comprises at least one of 2-pyrrolidinone, .beta.-thiodiglycol and 1,5-pentanediol.

Abstract: A water color ink for recording, including a yellow ink, a magenta ink and a cyan ink, wherein the yellow ink contains color index number Acid Yellow 23 at 0.7 to 3 wt %, the magenta ink contains a dye mixture of color index number Acid Red 52 and color index number Acid Red 289 at 0.7 to 3 wt %, and the cyan ink contains color index number Acid Blue 9 at 0.7 to 3 wt %, and an ink-jet recording process using the same.

Abstract: A water-based black recording ink comprises an aqueous medium and a colorant dissolved or dispersed therein, where the colorant comprises a first colorant, having a transmission color having L* of 4 or below and C*ab of 25 or below in the L*a*b* color system, and a second colorant, and a closed angle between the hue angle of the first colorant and that of the second colorant on the a*-b* plane in the L*a*b* color system is 90.degree. or greater.

Abstract: In an ink composition comprising a water-soluble dye or a pigment, dissolved or dispersed in an aqueous medium, the ink composition fulfills at least one of the following conditions 1 to 6 in respect of the concentration of metals contained therein:Condition 1; Barium concentration, not more than 4 ppmCondition 2; Zinc concentration, less than 1 ppmCondition 3; Nickel concentration, less than 0.05 ppmCondition 4; Strontium concentration, less than 0.01 ppmCondition 5; Iron concentration, not more than 0.3 ppmCondition 6; Silicon concentration, less than 1.5 ppm.

Abstract: An ink which is usable with an ink jetting device for jetting the ink through a nozzle so as to effect printing on a recording medium. The ink contains a pigment as a coloring agent, and a non-aqueous solvent as an ink solvent. The pigment is in the form of particles having an average particle size of X .mu.m. The ink is jetted from the ink jetting device at a rate of Y, where Y is the volume (pl) of the ink which is ejected from the nozzle each time the ink jetting device is energized. The above-indicated X and Y satisfy the following formulas:0.05 .ltoreq.X.ltoreq.0.5,10.ltoreq.Y.ltoreq.100X+50, and100X-30.ltoreq.Y.