Riso Kagaku Corporation

Toshihiro Endo

Shinichiro Shimura

Tetsuo Hosoya

Naoyuki Torita

Yasuo Yamamoto

Marie Morinaga

Kazuyuki Ando

Osamu Matsumoto

Hiroshi Hayashi

Kenji Yamada

Hikaru Sugiura

Naofumi Ezaki

Hiroyuki Ogawa

Teruaki Ohkawa

Yoshifumi Watanabe

Tadayuki Wakatabi

Masakatsu Arai

Shinsuke Ozawa

Akiko Yamamoto

Teruaki Okawa

Atsushi Tanaka

Hajime Tsunoda

Syotaro Kon

Shotaro Kon

Katsumi Kuriyama

Yoshiaki Matsuzawa

Ruri Watanabe

Kazuya Kawakami

Shin-Ichiro Shimura

Kohji Nomura

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.)

Oil-based inkjet ink

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

As a lubricant present between a transfer belt for transferring a print sheet and a platen plate on a rear side thereof and bringing the both into close contact, a lubricant containing 70 weight % or more of a fatty acid ester solvent with carbon number in a molecule of 20 or more and 34 or less is used so as to reduce sliding between the transfer belt and the platen plate and sliding resistance generated between the transfer belt for transferring the print sheet and an auxiliary plate arranged along this.

Image forming device

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.

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).

Inkjet printing process and non-aqueous ink set

The method is a non-aqueous inkjet printing method including the steps of: ejecting droplets of a non-aqueous pigment ink containing at least a pigment and a non-aqueous solvent onto a surface of a printing medium to form dots composed of the non-aqueous pigment ink, and then ejecting droplets of a non-aqueous post-treatment liquid containing at least silica and an organic solvent toward the printing medium so that the droplets overlap with the dots composed of the non-aqueous pigment ink, wherein either of the non-aqueous pigment ink and the post-treatment liquid contains a water-soluble resin having an amino group.

Non-aqueous inkjet printing method

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

In a non-aqueous pigment ink that includes pigment, a non-aqueous solvent, and a non-aqueous resin that functions to disperse pigment dissolved in the non-aqueous solvent, the non-aqueous solvent includes a hydrocarbon based non polar solvent at 50% by mass or more with respect to the total amount of solvent. The non-aqueous resin is an acrylic polymer having a comb shaped structure, in which alkyl groups having carbon numbers from 8 to 18 and urethane groups form side chains on a (meth)acrylate main chain. The acrylic polymer is a copolymer of an alkyl(meth)acrylate (A) having alkyl groups with a carbon number from 8 to 18, a reactive (meth)acrylate (B) having functional groups that react with amino groups, and a monomer (C) having &#x3b2;-diketone groups or &#x3b2;-keto acid ester groups, into which the urethane groups are introduced by reactions between the functional groups that react with amino groups, amino alcohol, and a multivalent isocyanate compound. The mass ratio between the copolymer moiety and the urethane group moiety in the acrylic polymer is from 80:20 to 99:1.

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.

[Problem to be solved] A non-aqueous ink, which has excellent pigment dispersion stability and can achieve reduction or elimination of print-through, thereby achieving high print density, is disclosed. [Solution] The non-aqueous ink contains at least a pigment and an organic solvent, wherein the organic solvent contains a five-membered heterocyclic compound having a C&#x2550;O bond in an amount of 50 mass % or more of the organic solvent, and the content of a polymer component in the ink is 20 mass % or less relative to the pigment.

Non-aqueous ink

A non-aqueous ink composition for inkjet printing, comprising 5 to 15% by mass of pigment relative to a mass of the non-aqueous ink composition, a pigment dispersant in such an amount that a mass ratio of the pigment dispersant to the pigment ranges from 0.2 to 2.0, and an organic solvent, the pigment dispersant comprising

Non-aqueous ink composition for inkjet printing

In an inkjet recording system using an ink in which a coloring material is dispersed in a solvent with a dispersing agent, printing density is improved by causing aggregation of the coloring material contained in the ink that has been ejected onto a printing medium. In an inkjet printing method, printing is performed by ejecting one of first and second inks onto a printing medium, and then successively ejecting the other ink so as to overlay it on the one ink. The first ink includes a first solvent, a coloring material, and a dispersing agent. The second ink includes at least a second solvent capable of changing solubility of the dispersing agent to cause aggregation of the coloring material when it is mixed with the first ink. For example, when one of the first and second solvents includes a water-insoluble organic solvent, the other can include a water-soluble organic solvent.

Inkjet printing method and ink set

An oily inkjet ink comprises a pigment, a dispersant, and a water-insoluble organic solvent, wherein an ester solvent contained in the water-insoluble organic solvent is an ester solvent that is represented by the general formula: CH&#x2014;COO&#x2014;CH, in which n represents an integral number falling within the range of 8 to 15, m represents an integral number falling within the range of 4 to 7, and x represents a number falling within the range of 2n&#x2212;1 to 2n+1. The ester solvent is contained in a containing quantity falling within the range of 10% by mass to 30% by mass with respect to the total quantity of the ink.

Oily inkjet ink

A non-aqueous pigment ink comprising a pigment, a pigment dispersant and a non-aqueous solvent, wherein the non-aqueous solvent comprises an alcohol solvent, a fatty acid ester solvent and a hydrocarbon solvent, the alcohol solvent comprises a saturated branched alcohol containing 14 to 18 carbon atoms and having one branch, and an amount of the saturated branched alcohol is within a range from 3 to 40% by mass relative to a total mass of the ink.

An inkjet ink is provided, which is hardly wettable to the surface of nozzle plates, and thus is stably ejected and is prevented from staining images. The inkjet ink is an oil-based inkjet ink which contains at least a pigment, a pigment-dispersing agent and a solvent constituted by at least an ester solvent, a salt of a long-chain polyaminoamide and a polar acidic ester in an amount of 1% by weight or more relative to the total amount of the ink.

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Ibaraki, Japan

Toshihiro Endo