Riso Kagaku Corporation

Tokyo University of Science Foundation

Teruaki Okawa

Hiroshi Hayashi

Shinichiro Shimura

Marie Morinaga

Hikaru Sugiura

Tomoko Matsuura

Yoshihiro Saito

Yoshiyuki Okada

Toshihiro Endo

Kazuyuki Ando

Kenji Shimomura

Naofumi Ezaki

Tetsuo Hosoya

Masakatsu Arai

Hidenori Otsuka

Shinsuke Ozawa

Masahiko Kusuhata

Naoyuki Torita

Syotaro Kon

Noriaki Sugawara

Masayuki Fukaishi

Takashi Ishizuka

Koji Ueno

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.

Oil-based inkjet ink

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

Non-aqueous pigment ink

A non-aqueous inkjet ink comprises silica and Brilliant Carmine 6B. A peak area obtained at the time of measurement of an organic acid quantity of a water extract of Brilliant Carmine 6B by use of a capillary electrophoresis apparatus is selected within the range of 50 to 300 mABU*sec.

Non-aqueous inkjet ink

An inkjet ink that prevents paper deformation such as curling, and also exhibits favorable pigment dispersibility. The inkjet ink includes at least a pigment, water, a water-soluble organic solvent having an &#x3b1; value of not more than 65, and a dispersant, wherein the dispersant is a copolymer having a unit A represented by general formula (a) shown below and a unit B represented by general formula (b) shown below, and the mass ratio between the water-soluble organic solvent and the water satisfies (water-soluble organic solvent)/water=5/5 to 8/2. [In general formula (a), Rrepresents a hydrogen atom or a lower alkyl group, and m represents an integer of 1 to 3.] [In general formula (b), Rand Reach represents a hydrogen atom or a lower alkyl group, wherein Rand Rmay be the same or different, and n represents an integer of 1 to 250.]

Inkjet ink

A printing apparatus is capable of forming images by overlappingly performing print processes for a plurality of colors with non-aqueous inks and an aqueous ink. When printing with the aqueous ink, it is possible to inhibit paper from being deformed and to realize a high density print process with a low see-through density. At least one of the plurality of colors is printed with a non-aqueous ink containing a water-insoluble solvent, and the remaining colors is printed with an aqueous ink containing a water-soluble solvent. The print process of the non-aqueous ink is performed in advance of the print process of the aqueous ink.

Printing apparatus

An emulsion ink for stencil printing is provided, which is high in transparency and does not hide previously a printed pattern when it is overlaid or printed on the pattern so as to facilitate multicolor printing with conventional stencil printing machines. The emulsion ink comprises an oil phase and a water phase and contains in the oil phase a coloring pigment together with an extending pigment that is insoluble in the oil phase, in which the ink has an optical density value of 1.0 or more as measured by a reflection densitometer when the ink is applied and dried in a thickness of 50 .mu.m onto a transparent sheet placed on a black standard board, and in which the ink has an optical density value of 0.7 or less as measured by the reflection densitometer when the transparent sheet is placed on a white standard board. Preferably, the coloring pigment constitutes 0.02 to 1%, and the extending pigment constitutes 1 to 5% by weight, of the total weight of the ink.

Emulsion ink for stencil printing

A medium for water-in-oil (W/O) emulsion ink for stencil printing is provided, which is useful for diluting the emulsion ink to obtain a transparent and pale color ink without lowering viscosity of the ink. The medium is a water-in-oil (W/O) emulsion comprising an oil phase and a water phase, in which the medium contains an extending pigment in the oil phase but is free from coloring pigments. The medium preferably has an optical density value of 1.4 or more as measured by a reflection densitometer when the medium is applied and dried in a thickness of 50 .mu.m onto a transparent sheet placed on a black standard board, and has 32 or less of flow value in one minute as measured by a spreadometer. The extending pigment preferably constitutes 1 to 5% by weight of the total weight of the medium, and may be inorganic fine particles or organic fine particles that are insoluble in said oil phase. The inorganic fine particles may be those subjected to lipophilic treatment.

Medium for emulsion ink for stencil printing

Growing community of inventors

Ibaraki-ken, Japan

Teruaki Okawa