Abstract: An ink for inkjet recording, which is used for recording on a paper having a concentration of an eluted Ca ion of from 1.0×10?4 to 5.0×10?4 g/g when dipped in pure water. The ink includes at least a pigment, a pigment dispersant, a water-soluble organic solvent and water. The pigment dispersant is a copolymer synthesized using at least (1) unsaturated ethylene monomer having a phosphoric acid group or a phosphonic acid group and (2) unsaturated ethylene monomer having an alkyl group having 12 to 22 carbon atoms.

Abstract: An ink for inkjet recording includes water; a water-soluble solvent; a pigment; and a copolymer including a salt of phosphonic acid group.

Abstract: An ink for inkjet recording includes water, a water-soluble solvent, a pigment and a copolymer including a salt of phosphonic acid group. The copolymer including a salt of phosphonic acid group includes structural units having the following formulae (1) and (2) or (3): wherein not less than half or all of M+ represent a cation of alkali metals or an organic ammonium ion, and the rest represents proton; wherein Ar1 represents a monovalent group of benzene or naphthalene; and wherein R1 represents an alkyl group having 5 to 20 carbon atoms.

Abstract: An ink composition contains a pigment represented by the following chemical formula 1; a hydrosoluble solvent; and water, wherein the pigment satisfies the following relation 1: 0.040<Y/X<0.200 (Relation 1), where, in a CuK? X-ray diffraction spectrum having a wavelength of 1.541 ?, X represents a peak intensity at a Bragg (2?±0.2°) angle in a range of 2? of from 26.5° to 27.5° and Y represents a peak intensity at a Bragg (2?±0.2°) angle in a range of 2? of from 11.0° to 11.

Abstract: An inkjet ink is provided. The inkjet ink includes water; a penetrant, a pigment, and a polymer compound. The polymer compound includes a unit (A) including a functional group having the below-mentioned formula (1) or (2), and another unit (B) including a carboxyl group. The unit (A) is included in the polymer compound in an amount of from 30% to 90% by weight based on the total weight of the polymer compound.

Abstract: Inkjet ink contains a pigment, a hydrosoluble solvent, and water, wherein the pigment is represented by the following chemical formula 1 and has a CuK? X-ray diffraction spectrum having a wavelength of 1.541 ? such that no main peak is observed at a Bragg (2?±0.2°) angle in a range of 2? of from 28.0° to 29.0°, wherein R represents a hydrogen atom, a methyl group, or a chlorine atom.

Abstract: An ink for inkjet recording including a pigment, a penetrating agent and water, wherein the pigment includes: an ozone-oxidized carbon black, including carbon black oxidized by ozone and having a volatile matter content of the carbon black of 10% by mass to 20% by mass and a BET specific surface area of 90 m2/g to 150 m2/g; and a resin-coated carbon black, including: carbon black; and a resin present on a surface of the carbon black.

Abstract: An inkjet recording ink, including: water; a wetting agent; a colorant; and polymer microparticles, wherein the polymer microparticles are each a copolymer of a monomer represented by the following structural formula (1) or the following general formula (2), a monomer represented by the following general formula (3), and a macromonomer represented by the following general formula (4): where “R1” is an alkyl group having 1 to 4 carbon atoms, where “Rs” are independently an alkyl group having 1 to 4 carbon atoms, where “l” is the number of repeating units, and an integer of 1 to 100.

Abstract: An inkjet recording ink including: water; a first pigment dispersion; a second pigment dispersion; and a penetrating agent, wherein the first pigment dispersion includes oxidized carbon black CB-1 dispersed therein with a pH of the first pigment dispersion adjusted to 6 to 8 with an alkali metal hydroxide, where the oxidized carbon black CB-1 is oxidized with ozone and has a volatile content of 10% to 20% and a BET specific surface area of 90 m2/g to 150 m2/g, and the second pigment dispersion includes carbon black CB-2 dispersed therein with a naphthalene sulfonic acid-formalin condensate, where the carbon black CB-2 has an average particle diameter (D50) of 50 nm to 180 nm as measured by a dynamic light scattering method and a standard deviation of particle diameters of the carbon black CB-2 is equal to or lower than ½ of the average particle diameter.

Abstract: A heat-sensitive stencil is disclosed which includes a porous substrate having opposing first and second surfaces, and a thermoplastic resin film bonded to the first surface of the substrate with an adhesive, wherein the second surface of the substrate is negative to a wax No. 6 pick test defined in the specification herein so that the fibers constituting the substrate are not picked off during its contact with a platen roller in the master forming stage.

Abstract: A thermosensitive stencil paper is composed of a thermosensitive stencil film and an overcoat layer formed thereon which contains a higher-alcohol-ester-modified silicone oil as a sticking-prevention agent. A porous substrate may be attached to the back side of the stencil film by use of an adhesive agent.

Abstract: A thermosensitive stencil paper is composed of a substrate and a thermoplastic resin film formed thereon, which thermoplastic resin film has projections in the surface portion thereof, with a printing roughness (R.sub.p) of 2.2 to 5.0 .mu.m, which is a physical quantity proportional to the average depth of the depressions in the surface portion thereof pressed against a standard surface.

Abstract: A thermosensitive stencil paper in which a thermoplastic resin layer is formed on a porous tissue paper containing natural fibers therein, serving as a porous substrate, with plant elements contained in the porous tissue paper selected in such a fashion that (1) plant elements having a maximum width ranging from 100 .mu.m to 5 mm, a maximum length ranging from 100 .mu.m to 5 mm, and an area of 7800 .mu.m.sup.2 or more, when measured in a posture which provides a maximum area of the plant element are present in a number of 150 or less in a 100 cm.sup.2 area of the porous tissue paper; and (2) plant elements having a maximum width ranging from 300 .mu.m to 5 mm, a maximum length ranging from 300 .mu.m to 5 mm, and an area of 70,000 .mu.m.sup.2 or more are present in a number of 25 or less in a 100 cm.sup.2 area of the porous tissue paper.