Riso Kagaku Corporation

Marie Morinaga

Shinichiro Shimura

Kazuyuki Ando

Hikaru Sugiura

Shinsuke Ozawa

Toshihiro Endo

Tetsuo Hosoya

Naoyuki Torita

Hiroshi Hayashi

Naofumi Ezaki

Teruaki Okawa

Noriaki Sugawara

Yoshifumi Watanabe

Kazuya Kawakami

Provided is an oil-based inkjet ink containing a pigment and a fatty acid ester-based solvent represented by general formula (1) shown below and having at least 18 but not more than 29 carbon atoms per molecule. In general formula (1), Rrepresents an alkyl group of 5 or more carbon atoms, Rrepresents an alkyl group of 6 or more carbon atoms, and at least one of Rand Ris a branched alkyl group of 9 or more carbon atoms having a side chain of 4 or more carbon atoms. 

Oil-based inkjet ink

An oil-based inkjet ink can be provided which prevents dye conversion of a dye lake pigment contained in the ink, prevents adhesion of the ink to the nozzle plate, and yields excellent drying properties for printed items. The oil-based inkjet ink contains a dye lake pigment, a pigment dispersant and a non-aqueous solvent, wherein the non-aqueous solvent contains a silicone oil having a surface tension of at least 20 mN/m but not more than 28 mN/m. The surface tension of the silicone oil is preferably at least 22 mN/m but not more than 26 mN/m.

An oil-based inkjet ink set is disclosed that includes: an oil-based inkjet ink A containing a non-aqueous solvent, the non-aqueous solvent of the oil-based inkjet ink A containing at least 15% by mass of a silicone oil relative to the total mass of the non-aqueous solvent of the oil-based inkjet ink A, and an oil-based inkjet ink B containing a non-aqueous solvent, the non-aqueous solvent of the oil-based inkjet ink B containing at least 50% by mass of a petroleum-based hydrocarbon solvent relative to the total mass of the non-aqueous solvent of the oil-based inkjet ink B. A method for producing a printed item is also disclosed.

Oil-based inkjet ink set and method for producing printed item

An oil-based inkjet ink is disclosed, the oil-based inkjet ink containing a pigment, a pigment dispersant and a non-aqueous solvent, wherein the pigment contains an acidic carbon black having a pH of 2 to 6, the non-aqueous solvent contains a modified silicone oil having a surface tension of not more than 27 mN/m, and an amount of the modified silicone oil, relative to a total mass of the oil-based inkjet ink, is at least 15% by mass but not more than 80% by mass.

An oil-based inkjet ink can be provided which exhibits excellent discharge stability even after a long idle period, and also yields high image density and prevents show-through in printed items. The oil-based inkjet ink contains a pigment, an amide-based dispersant and a non-aqueous solvent, wherein the non-aqueous solvent contains a modified silicone oil having 2 or 3 silicon atoms in one molecule, and a petroleum-based hydrocarbon solvent.

A method for producing a printed item including discharging two or more inks by an inkjet method toward a recording medium to form an image is disclosed, wherein the two or more inks include a first oil-based inkjet ink containing a first colorant and a non-aqueous solvent and having an ink surface tension of less than 27.0 mN/m, and a second oil-based inkjet ink containing a second colorant and a non-aqueous solvent and having an ink surface tension of 27.0 mN/m or greater, and the method includes discharging the first oil-based inkjet ink toward the recording medium at a discharge volume of at least 20 pl per one liquid droplet to form dots with the first oil-based inkjet ink, and subsequently discharging the second oil-based inkjet ink toward the recording medium at a discharge volume of less than 20 pl per one liquid droplet so as to overlap with the dots formed with the first oil-based inkjet ink.

Method for producing printed item

Disclosed is an oil-based inkjet ink containing a colorant and a non-aqueous solvent, wherein the non-aqueous solvent contains at least 15% by mass but not more than 100% by mass, relative to the total mass of the non-aqueous solvent, of an organosilicon compound having 2 to 6 silicon atoms in one molecule, having an organic group in which a carbon atom is bonded directly to a silicon atom and in which the total number of carbon atoms and oxygen atoms is at least 4, and having a total number of carbon atoms and oxygen atoms, contained within all of the organic groups in which the total number of carbon atoms and oxygen atoms is at least 4, that is from 4 to 20 within one molecule.

An oil-based inkjet is disclosed, the oil-based inkjet ink containing a pigment, a pigment dispersant and a non-aqueous solvent, wherein the non-aqueous solvent contains a silicone oil having a surface tension of at least 19.0 mN/m but less than 24.0 mN/m and a polar solvent having a surface tension of at least 27.0 mN/m, and a surface tension of the ink is at least 23.0 mN/m but less than 27.0 mN/m.

An inkjet printer includes: an oil-based ink containing silicone oil; and inkjet heads each including a nozzle row in which nozzles configured to eject the oil-based ink to a print medium conveyed in a conveyance direction are arranged, the inkjet heads being arranged adjacent to each other with the nozzles in each nozzle row arranged in a direction non-orthogonally intersecting the conveyance direction.

Inkjet printer using oil-based ink

A non-aqueous pigment ink includes a pigment, a non-aqueous solvent, a non-water-soluble resin and a water-soluble resin, wherein the non-water-soluble resin is an acrylic polymer formed by a copolymer of a monomer mixture containing at least an alkyl (meth)acrylate (A) having a C8 to C18 alkyl group and a monomer (B) having a &#x3b2;-diketone group or &#x3b2;-keto acid ester group.

Non-aqueous pigment ink

A non-aqueous pigment ink includes a pigment, a non-aqueous solvent, a non-water-soluble resin and a water-soluble resin, wherein the non-water-soluble resin is an acrylic polymer formed by a copolymer of a monomer mixture containing at least an alkyl(meth)acrylate (A) having a C8 to C18 alkyl group and a monomer (B) having a &#x3b2;-diketone group or &#x3b2;-keto acid ester group.

A non-aqueous inkjet ink containing at least two kinds of color pigments, a pigment dispersing agent and an organic solvent, wherein the two kinds of color pigments are a watching red pigment and a benzimidazolone pigment.

Non-aqueous inkjet ink

A non-aqueous pigment ink that exhibits excellent color reproducibility and storage stability. The non-aqueous pigment ink contains two or more lake pigments and a non-aqueous solvent.

A non-aqueous ink composition for inkjet printing is provided, which comprises 0.01 to 10 wt % of at least one ionic substance (A) selected from the group consisting of quarterly ammonium salts, quarterly phosphonium salts, a combination of a fatty acid and/or an alkyl phosphate with an amine compound, and synergists, 0.1 to 20 wt % of an Calkyl(meth)acrylate copolymer (B) having 1 to 40 wt %, relative to a weight of the copolymer, of urethane moiety, 0.1 to 20 wt % of a pigment (C), and an organic solvent (D). The composition achieves excellent wiping durability and printed image density.

Ink composition for inkjet printing

A non-aqueous pigment ink comprising a pigment, a non-aqueous solvent, and non-aqueous resin dispersion microparticles having a pigment dispersion capability, wherein the non-aqueous resin dispersion microparticles are an acrylic polymer comprising an alkyl (meth)acrylate unit having an alkyl group of 12 or more carbon atoms and a (meth)acrylate unit having a urethane group. The acrylic polymer is a copolymer of a monomer mixture comprising an alkyl (meth)acrylate (A) having an alkyl group of 12 or more carbon atoms and a reactive (meth)acrylate (B) having a functional group capable of reacting with an amino group, wherein the urethane group is introduced by a reaction between the functional group capable of reacting with an amino group, an amino alcohol and a polyvalent isocyanate compound, and the mass ratio within the acrylic polymer between the copolymer portion and the introduced urethane group portions is within a range from 60:40 to 99:1.

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Ibaraki, Japan

Marie Morinaga