Riso Kagaku Corporation

Shinichiro Shimura

Kazuyuki Ando

Marie Morinaga

Hikaru Sugiura

Toshihiro Endo

Shinsuke Ozawa

Naofumi Ezaki

Naoyuki Torita

Tetsuo Hosoya

Hiroshi Hayashi

Teruaki Okawa

Noriaki Sugawara

Shunsuke Uozumi

Akiko Yamamoto

Sayako Arai

Takayuki Shimizu

Masahiko Abe

Mitsuko Kitanohara

Hideki Sakai

Tetsuya Shiraishi

Tsutomu Nio

Sadano Okuda

Kenichi Sakai

Tsukasa Hamada

An oil-based inkjet ink is disclosed that contains a pigment, a dispersant formed with an acidic resin, a low-molecular weight amine compound and a basic polymer, and a non-aqueous solvent. A method for producing an oil-based inkjet ink and a method for producing a dispersant is also disclosed.

Oil-based inkjet ink, method for producing oil-based inkjet ink and method for producing dispersant

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 that prevents adhesion of the ink to the nozzle plate, thereby preventing ink misfires and discharge defects from the inkjet nozzles. The oil-based inkjet ink contains a pigment, a non-aqueous solvent, and a compound represented by general formula (1) shown below. (In general formula (1), m represents 1 or 2, each of Rand Rindependently represents a monovalent saturated hydrocarbon group, Rrepresents a single bond or a divalent saturated hydrocarbon group, and Rrepresents a monovalent or divalent saturated hydrocarbon group.)

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 colorant and a non-aqueous solvent, wherein the non-aqueous solvent contains a silicone oil having a boiling point higher than 250&#xb0; C. and a fatty acid ester-based solvent having 10 to 30 carbon atoms.

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

An oil-based inkjet ink set including two or more liquid compositions, for use with an inkjet head having two or more discharge port arrays, wherein at least one of the two or more liquid compositions is an oil-based inkjet ink, the initial boiling point of each of the two or more liquid compositions is, independently, 280&#xb0; C. or higher, and the difference in the specific gravities of any pair of liquid compositions in the two or more liquid compositions is at least 0.005 but not more than 0.012, is disclosed. A method for producing a printed item is also disclosed.

A nonaqueous inkjet printing method that can provide prints with both high printing density and good gradation is provided. The nonaqueous inkjet printing method comprises printing an image by an inkjet recording system using a first nonaqueous ink comprising at least a coloring pigment, a water-soluble resin having an amino group, and a nonaqueous solvent, and then printing an image so as to overlap with the preceding image by an inkjet recording system using a second nonaqueous ink, wherein the second nonaqueous ink comprises at least a coloring pigment, inorganic particles, and a nonaqueous solvent, and the content of the coloring pigment in the second nonaqueous ink is lower than the content of the coloring pigment in the first nonaqueous ink. The first nonaqueous ink is preferably printed at a higher resolution of printing than the second nonaqueous ink.

Nonaqueous inkjet printing method

An inkjet printing process including forming an image by superposing two or more kinds of inks, wherein the two or more kinds of inks contain (A) an ink containing at least a first coloring material, a non-aqueous solvent, a non-aqueous resin, and a water-soluble resin having an amino group, and (B) an ink containing at least a second coloring material, a non-aqueous solvent, and a nitrogen-containing graft copolymer having a polyester side chain, and a non-aqueous ink set containing the ink (A) and the ink (B).

Growing community of inventors

Ibaraki, Japan

Shinichiro Shimura