Abstract: An aqueous ink for ink jet contains a urethane resin. The urethane resin has a unit derived from a polyether polyol and a unit containing an acidic group. The acid value of the urethane resin is 40 to 140 mg KOH/g. The molar ratio of urethane bonds/urea bonds is 80.0/20.0 or more. Some of the acidic groups in the urethane resin are neutralized with particular neutralizing agents.

Abstract: An ink used for an inkjet recording method for discharging the ink from a recording head by an action of thermal energy contains self-dispersing carbon black, a polyurethane polymer having an acid value of 40 mg KOH/g or more, and polyethylene glycol.

Abstract: An ink jet ink containing a pigment and a polyurethane polymer, wherein the polyurethane polymer has units derived from a polyol having no acid group and having the carbon number of 13 or more and 250 or less, a diol having an acid group and having the carbon number of 1 or more and 7 or less, a polyol having a siloxane structure, and a polyisocyanate, and an acid value of the polyurethane polymer is 40.0 mgKOH/g or more and 80.0 mgKOH/g or less.

Abstract: An ink for ink jet contains a pigment and a urethane resin. The pigment is at least one of a pigment the particles of which have an anionic group bonded to their surface directly or via another atomic group and a pigment dispersed by a resin having an anionic unit and different from the urethane resin. The urethane resin has a unit derived from a polyfunctional polyisocyanate, and this unit has at least one structure selected from the group consisting of an allophanate structure that has added a monohydric alcohol containing 1 to 5 carbon atoms, a uretdione structure, an isocyanurate structure, and a biuret structure. The acid value of the urethane resin is less than 10 mg KOH/g.

Abstract: An ink jet ink includes a pigment and a polyurethane polymer having units derived from a polyisocyanate, a polyol, and a diol having an acid group, and in the ink jet ink described above, an acid value of the polyurethane polymer is 20 mgKOH/g or more and 100 mgKOH/g or less, the unit derived from the polyisocyanate includes a unit derived from a compound represented by the following general formula (I), and the proportion of the unit derived from the compound represented by the general formula (I) in the unit derived from the polyisocyanate is 90 percent by mole or less.

Abstract: An ink to be applied to a recording head having a common liquid chamber, pressure chambers developing pressure applied to the liquid, individual channels through which the liquid is introduced into the pressure chambers from the common liquid chamber, and a group of nozzles which communicate with the pressure chambers and eject the liquid, where first nozzles having short individual channels and second nozzles having long ones are alternately arranged at arrangement intervals of less than 30 ?m along one side or sides of the common liquid chamber, contains an aqueous medium, a surfactant and a coloring material. The aqueous medium consists of water and a water-soluble organic compound containing at least one alkanediol and has a surface tension of from 40 mN/m or more to less than 60 mN/m in an environment of temperature 25° C. and humidity 50%.

Abstract: An ink jet ink contains a self-dispersing pigment and a polyurethane polymer. The polyurethane polymer has units derived from a polyisocyanate, a polyol having no acid group, and a diol having an acid group. The polyurethane polymer has a cross-linked structure and an acid value of the polyurethane polymer is 60 mgKOH/g or more and 100 mgKOH/g or less.

Abstract: An ink jet ink contains a polyurethane polymer and a pigment. The polyurethane polymer has units derived from a polyisocyanate, a polyether polyol having no acid group, and a diol having an acid group. The pigment is dispersed using a polymer other than the polyurethane polymer. The molar ratio of the percentage of the urethane bond in the polyurethane polymer to the percentage of the urea bond in the polyurethane polymer is 85.0/15.0 or more and 100.0/0 or less.

Abstract: An ink jet ink contains a polyurethane polymer and a pigment. The polyurethane polymer has units derived from a polyisocyanate, a polyether polyol having no acid group, and a diol having an acid group. The pigment is dispersed using a polymer other than the polyurethane polymer. The ratio of the percentage of the urethane bond in the polyurethane polymer to the percentage of the urea bond in the polyurethane polymer is 85.0/15.0 or more and 98.5/1.5 or less.

Abstract: An ink jet ink including a pigment and an ABC triblock polymer, wherein the above-described ABC triblock polymer is formed from an A block having an aryl group, a B block having a unit represented by the following general formula (1), and a C block having a unit represented by the following general formula (2).

Abstract: An ink jet ink contains a pigment and a polyurethane polymer. The polyurethane polymer contains units derived from a polyisocyanate, a polyol, a compound having a carboxy group, and a compound having a sulfo group, and an acid value of the polyurethane polymer is 20 mgKOH/g or more and 100 mgKOH/g or less.

Abstract: To provide an ink jet ink that produces an image having high optical density, scratch resistance, and highlighter resistance, has excellent ink ejection stability, and can reduce image deflection caused by face wetting. The ink jet ink contains a polyurethane polymer and a self-dispersing pigment. The polyurethane polymer has units derived from a polyisocyanate, a polyol having no acid group, and a diol having an acid group. The molar ratio of the percentage of the urethane bond in the polyurethane polymer to the percentage of the urea bond in the polyurethane polymer is 85.0/15.0 or more and 100.0/0 or less.

Abstract: An ink to be applied to a recording head having a common liquid chamber, pressure chambers developing pressure applied to the liquid, individual channels through which the liquid is introduced into the pressure chambers from the common liquid chamber, and a group of nozzles which communicate with the pressure chambers and eject the liquid, where first nozzles having short individual channels and second nozzles having long ones are alternately arranged at arrangement intervals of less than 30 ?m along one side or sides of the common liquid chamber, contains an aqueous medium, a surfactant and a coloring material. The aqueous medium consists of water and a water-soluble organic compound containing at least one alkanediol and has a surface tension of from 40 mN/m or more to less than 60 mN/m in an environment of temperature 25° C. and humidity 50%.

Abstract: The invention provides an ink containing a polyurethane polymer which has units respectively derived from a polyisocyanate, a polyether polyol having no acid group and a diol having an acid group and has an acid value of 40 mg KOH/g or more and 140 mg KOH/g or less, a carbon black and at least one antioxidant selected from compounds represented by the general formulae (1) to (3).

Abstract: An ink used for an inkjet recording method for discharging the ink from a recording head by an action of thermal energy contains self-dispersing carbon black, a polyurethane polymer having an acid value of 40 mg KOH/g or more, and an acryl polymer having an acid value of 100 mg KOH/g or more and 200 mg KOH/g or less.

Abstract: The invention provides an ink containing a self-dispersion pigment in which a phosphonic acid group is bonded directly or through another atomic group to the surface thereof and a polyurethane polymer, wherein the surface charge amount of the self-dispersion pigment is 0.25 mmol/g or more and 0.42 mmol/g or less, and the polyurethane polymer has units respectively derived from a polyisocyanate, a polyether polyol having no acid group and a diol having an acid group.

Abstract: An ink used for an inkjet recording method for discharging the ink from a recording head by an action of thermal energy contains self-dispersing carbon black, a polyurethane polymer having an acid value of 40 mg KOH/g or more, and polyethylene glycol.

Abstract: An ink to be applied to a recording head having a common liquid chamber, pressure chambers developing pressure applied to the liquid, individual channels through which the liquid is introduced into the pressure chambers from the common liquid chamber, and a group of nozzles which communicate with the pressure chambers and eject the liquid, where first nozzles having short individual channels and second nozzles having long ones are alternately arranged at arrangement intervals of less than 30 ?m along one side or sides of the common liquid chamber, contains an aqueous medium, a surfactant and a coloring material. The aqueous medium consists of water and a water-soluble organic compound containing at least one alkanediol and has a surface tension of from 40 mN/m or more to less than 60 mN/m in an environment of temperature 25° C. and humidity 50%.

Abstract: An ink jet ink contains a self-dispersing pigment and a polyurethane polymer. The polyurethane polymer has units derived from a polyisocyanate, a polyol having no acid group, and a diol having an acid group. The polyurethane polymer has a cross-linked structure and an acid value of the polyurethane polymer is 60 mgKOH/g or more and 100 mgKOH/g or less.

Abstract: An ink jet ink contains a polyurethane polymer and a pigment. The polyurethane polymer has units derived from a polyisocyanate, a polyether polyol having no acid group, and a diol having an acid group. The pigment is dispersed using a polymer other than the polyurethane polymer. The molar ratio of the percentage of the urethane bond in the polyurethane polymer to the percentage of the urea bond in the polyurethane polymer is 85.0/15.0 or more and 100.0/0 or less.