Abstract: The inkjet head for discharging a water-based ink for inkjet recording is disclosed, the inkjet head including two or more types of metal members used at portions to be brought in contact with the water-based ink, wherein at least two of the two or more types of the metal members are electrically connected, and the two or more types of the electrically connected metal members have spontaneous potentials each of which is measured with a reference electrode Ag/AgCl in the water-based ink and which provide an absolute value of a maximum difference therebetween, the absolute value being not more than 60 mV. An ink jet head is provided, in which any corrosion of a metal member is suppressed.

Abstract: Disclosed is a treatment solution for ink jet recording, including: an aggregating agent; water; and tetraethylene glycol monobutyl ether and pentaethylene glycol monobutyl ether, wherein: tetraethylene glycol monobutyl ether and pentaethylene glycol monobutyl ether are contained by 1 % by weight to 10 % by weight in total in the treatment solution; and a weight ratio (X:Y) of tetraethylene glycol monobutyl ether (X) to pentaethylene glycol monobutyl ether (Y) is 50:50 to 90:10.

Abstract: Disclosed is a water-based ink for ink jet recording, including: a colorant; water; and tetraethylene glycol monobutyl ether and pentaethylene glycol monobutyl ether, wherein: tetraethylene glycol monobutyl ether and pentaethylene glycol monobutyl ether are contained by 1% by weight to 10% by weight in total in the water-based ink for ink jet recording; and a weight ratio (X:Y) of tetraethylene glycol monobutyl ether (X) to pentaethylene glycol monobutyl ether (Y) is 50:50 to 90:10.

Abstract: A treatment liquid for ink jet recording, containing a polyvalent metal ion and water. A dissolved carbon dioxide concentration in the treatment liquid is 4 mg/l or lower.

Abstract: The inkjet head for discharging a water-based ink for inkjet recording is disclosed, the inkjet head including two or more types of metal members used at portions to be brought in contact with the water-based ink, wherein at least two of the two or more types of the metal members are electrically connected, and the two or more types of the electrically connected metal members have spontaneous potentials each of which is measured with a reference electrode Ag/AgCl in the water-based ink and which provide an absolute value of a maximum difference therebetween, the absolute value being not more than 60 mV. An ink jet head is provided, in which any corrosion of a metal member is suppressed.

Abstract: There is provided an image forming apparatus for forming an image on a recording medium, the image forming apparatus including: a first discharge head which discharges, toward the recording medium, an ink containing a coloring agent; a second discharge head which discharges, toward the recording medium, a liquid which improves image quality and which contains a component for coagulating or depositing the coloring agent; an energy emitting device which emits active energy; and a transport mechanism which transports the recording medium to a position opposed to the first discharge head and the second discharge head, wherein: at least one of the ink and the liquid contains a curable substance which is curable by being irradiated with the active energy.

Abstract: Disclosed is a treatment solution for ink jet recording, including: an aggregating agent; water; and tetraethylene glycol monobutyl ether and pentaethylene glycol monobutyl ether, wherein: tetraethylene glycol monobutyl ether and pentaethylene glycol monobutyl ether are contained by 1% by weight to 10% by weight in total in the treatment solution; and a weight ratio (X:Y) of tetraethylene glycol monobutyl ether (X) to pentaethylene glycol monobutyl ether (Y) is 50:50 to 90:10.

Abstract: Disclosed is a water-based ink for ink jet recording, including: a colorant; water; and tetraethylene glycol monobutyl ether and pentaethylene glycol monobutyl ether, wherein: tetraethylene glycol monobutyl ether and pentaethylene glycol monobutyl ether are contained by 1% by weight to 10% by weight in total in the water-based ink for ink jet recording; and a weight ratio (X:Y) of tetraethylene glycol monobutyl ether (X) to pentaethylene glycol monobutyl ether (Y) is 50:50 to 90:10.

Abstract: There is provided an image forming apparatus for forming an image on a recording medium, the image forming apparatus including: a first discharge head which discharges, toward the recording medium, an ink containing a coloring agent; a second discharge head which discharges, toward the recording medium, a liquid which improves image quality and which contains a component for coagulating or depositing the coloring agent; an energy emitting device which emits active energy; and a transport mechanism which transports the recording medium to a position opposed to the first discharge head and the second discharge head, wherein: at least one of the ink and the liquid contains a curable substance which is curable by being irradiated with the active energy.

Abstract: A treatment liquid for ink jet recording, containing a polyvalent metal ion and water. A dissolved carbon dioxide concentration in the treatment liquid is 4 mg/l or lower.

Abstract: A water base ink for ink-jet recording contains a self-dispersible coloring agent, a propylene glycol ether, and a surfactant represented by the following general formula (3): R1—O—(CH2CH2O)n—SO3M??(3) wherein R1 represents an alkyl group having a number of carbon atoms of 12 to 15, M represents Na or triethanolamine, and n represents an integer of 2 to 4, and wherein the propylene glycol ether is dipropylene glycol propyl ether. The ink satisfies three requirements of i) the satisfactory initial introduction performance of the ink into an ink flow passage of a stacked type printer head, ii) the prevention of the occurrence of feathering, and iii) the prevention of the insufficient spread of the ink.

Abstract: A water-based ink for ink-jet recording enables the expression of sharp text and lines in high density black, and the formation of a high quality gradation image in which the graininess is reduced in a black image of medium to high lightness. The inks include a color ink (A) and a color ink (B) each of which independently has a lightness index L* according to the L* a* b* calorimetric system of about 60 or less. The color ink (A) and the color ink (B) satisfy the following expression (I): about 120°?|???| about ?240°??(I) wherein ? is the hue angle of the color ink (A) and ? is the hue angle of the color ink (B). The chroma C* of a hue obtained by the combination of the color ink (A) and the color ink (B) is about 30 or less.

Abstract: A water-based ink for ink-jet recording and an ink-jet recording method allow the formation of sharp text and lines in high density black, and the formation of a high quality gradation image in which the graininess is reduced in a black image of a medium lightness to a high lightness (e.g., an achromatic image in dark gray to light gray) in ink-jet recording. The water-based ink combination for ink-jet recording comprises a black ink, and a color ink (A) and a color ink (B) that satisfy a color relationship of the following expression (I): about 120°?|?-?|?about 240°??(I) wherein ? is the hue angle of the color ink (A) and ? is the hue angle of the color ink (B).

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-based ink for ink-jet recording and an ink-jet recording method allow the formation of sharp text and lines in high density black, and the formation of a high quality gradation image in which the graininess is reduced in a black image of a medium lightness to a high lightness (e.g., an achromatic image in dark gray to light gray) in ink-jet recording. The water-based ink combination for ink-jet recording comprises a black ink, and a color ink (A) and a color ink (B) that satisfy a color relationship of the following expression (I): about 120°?|???|?about 240°??(I) wherein ? is the hue angle of the color ink (A) and ? is the hue angle of the color ink (B).

Abstract: According embodiments of the present disclosure, a water-based ink set for ink-jet recording is provided. The ink set may contain a black ink, a cyan ink, a magenta ink and a yellow ink. Each ink may contain a polyoxyethylene alkyl ether sulfonate.

Abstract: A water base ink for ink-jet recording contains self-dispersible carbon black as a coloring agent. The total content of an organic acid having a number of carbon or carbons of 1 to 6 and a salt of the organic acid is not more than 400 ppm. The organic acid having a number of carbon or carbons of 1 to 6 includes monocarboxylic acid, dicarboxylic acid and oxy acid, and the salt of the organic acid includes salts of these acids. When the water base ink is used in an ink-jet recording apparatus, the discharge stability of the ink is improved.

Abstract: The water-based ink set for ink-jet recording includes a magenta ink and a red ink with dynamic surface tensions thereof satisfying the following inequalities (IM), (IIM), (IIIM) and (IVM) ?30M?about 49 mN/m??(IM) ?30M+?30R?about 100 mN/m??(IIM) wherein ?30M is the dynamic surface tension of the magenta ink at a lifetime of 30 ms and ?30R is the dynamic surface tension of the red ink at a lifetime of 30 ms, ?1000R?about 36 mN/m??(IIIM) ?1000M+?1000R?about 70 mN/m??(IVM) wherein ?1000M is the dynamic surface tension of the magenta ink at a lifetime of 1,000 ms and ?1000R is the dynamic surface tension of the red ink at a lifetime of 1,000 ms).

Abstract: The water-based ink set for ink-jet recording includes a cyan ink and a blue ink with dynamic surface tensions thereof satisfying the following inequalities (ICB), (IICB), (IIICB) and (IVCB) ?30C?about 49 mN/m??(ICB) ?30C+?30B?about 100 mN/m??(IICB) wherein ?30C is the dynamic surface tension of the cyan ink at a lifetime of 30 ms and ?30B is the dynamic surface tension of the blue ink at a lifetime of 30 ms, ?1000B?about 36 mN/m??(IIICB) ?1000C+?1000B?about 70 mN/m??(IVCB) wherein ?1000C is the dynamic surface tension of the cyan ink at a lifetime of 1,000 ms and ?1000B is the dynamic surface tension of the blue ink at a lifetime of 1,000 ms.

Abstract: A water base ink for ink-jet recording contains self-dispersible carbon black as a coloring agent. The total content of an organic acid having a number of carbon or carbons of 1 to 6 and a salt of the organic acid is not more than 400 ppm. The organic acid having a number of carbon or carbons of 1 to 6 includes monocarboxylic acid, dicarboxylic acid and oxy acid, and the salt of the organic acid includes salts of these acids. When the water base ink is used in an ink-jet recording apparatus, the discharge stability of the ink is improved.