Kao Corporation

Isao Tsuru

Ryuma Mizushima

Takehiro Tsutsumi

Koji Azuma

Yusuke Shimizu

Hiroyuki Yoshida

Yoko Hanada

Yasunori Hosokawa

Tadashi Igarashi

Yasufumi Ueda

Yukihiro Nakano

Hirotaka Takeno

Takahiro Sato

Michitaka Sawada

Nobushige Tanaka

Norihiro Yoshida

Masato Hoshi

Tomoaki Il

Hironobu Fukuroi

Hideki Sakai

Jun Tairadate

Kimiya Yamada

Katsuhiko Inada

Yoshiharu Niizeki

Kohji Azuma

Tomoaki Ii

The present invention relates to an ink-jet printing method using an apparatus including a printing means for ejecting a black ink to a printing substrate to print characters or images on the printing substrate, and a drying means disposed on a downstream side of a transportation direction of the printing substrate, in which the printing substrate is a label printing substrate; the black ink is a water-based composite black ink; the water-based composite black ink contains a composite black pigment containing carbon black, and a content of the carbon black in the composite black pigment is not more than 25% by mass; and the drying means is an infrared heater for heating the water-based composite black ink ejected onto the printing substrate to a temperature of not lower than 95&#xb0; C. and not higher than 125&#xb0; C. According to the ink-jet printing method of the present invention, it is possible to obtain a good printed material that is free of color migration or deformation of a printing substrate even when printed on a label printing substrate.

Ink jet recording method

The present invention provides the following process for producing a fine organic pigment which is capable of producing the fine organic pigment that has a very small primary particle size and is excellent in filtering property even in a cleaning step, and a fine organic pigment produced by the process; a process for producing a dispersion using the fine organic pigment, and a dispersion produced by the process; and a process for producing an ink using the dispersion. The present invention relates to [1] a process for producing a fine organic pigment, including steps 1 and 2: step 1: kneading a mixture prepared by compounding a raw material organic pigment, a water-soluble inorganic salt, a water-soluble organic solvent and a compound represented by the following formula (1) with each other, the compound being compounded in an amount of not less than 0.8 part by mass and not more than 18.0 parts by mass on the basis of 100 parts by mass of the raw material organic pigment:

Production method for fine organic pigment

The present invention relates to a water-based ink for ink-jet printing which exhibits a high optical density even upon one-pass printing on plain papers and is suitable for high-speed printing, and a dispersion used in the water-base ink. There are provided a water dispersion for ink-jet printing, including water-insoluble polymer particles containing a colorant, and a nonionic organic compound satisfying the following conditions I and II:

Water-based inks for ink-jet printing

There are provided a water dispersion for ink-jet printing which contains a water dispersion of particles of a vinyl polymer or a polyester-based polymer which contain a colorant (B), and a water-insoluble organic compound (A) except for aliphatic acid derivatives; a water-based ink containing the water dispersion; a print obtainable by printing images or characters with the water-based ink; and a process for producing the water dispersion. Also, there are provided an ink set for ink-jet printing containing two or more kinds of inks having different colors from each other wherein the inks each contain a water dispersion of particles of a vinyl polymer or a polyester-based polymer which contain a colorant (B), and a water-insoluble organic compound (A) except for aliphatic acid derivatives; and a process for producing a print using the ink set. The water-based ink can provide multi-order color images or composite black images which exhibits a high optical density and is excellent in gloss and image clarity.

A water dispersion containing colorant-containing water-insoluble vinyl polymer particles, and a water-based ink containing the water dispersion. The water-insoluble vinyl polymer contains constitutional units of formulae (1) and (2): where Ris a hydrogen atom or a methyl group; and Ris a substituted or unsubstituted arylalkyl group or a substituted or unsubstituted aryl group; and where Ris a hydrogen atom or a methyl group; RO is an oxypropylene group; RO is an oxyalkylene group having 2 or 4 carbon atoms; Ris a hydrogen atom, an alkyl group or an unsubstituted or alkyl-substituted phenyl group; x is a number from 1 to 30; and y is a number from 0 to 30, and a weight ratio of the constitutional units of formula (1) to formula (2) in the polymer ranges from 1/2 to 10/1.

The present invention relates to a water dispersion for ink-jet printing, including a colorant, particles (A) (except for pigments) having a refractive index of 1.0 to 2.2, and a nonionic organic compound containing a saturated or unsaturated hydrocarbon group having 8 to 30 carbon atoms, and exhibiting a solubility of 1 g or less in 100 g of water as measured at 25&#xb0; C., as well as a water based ink containing the water dispersion. There are provided a water-based ink for ink-jet printing which can exhibit a high optical density upon one-pass printing on plain papers and, therefore, is suitable for high-speed printing, as well as a water dispersion used in the water-based ink.

The present invention relates to a water dispersion for ink jet recording, comprising water-insoluble vinyl polymer particles containing a colorant, wherein the water-insoluble vinyl polymer is a water-insoluble vinyl polymer obtained by polymerizing a monomer mixture comprising: wherein Rrepresents a hydrogen atom or a methyl group, Rrepresents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or a phenyl group whose hydrogen atom may be substituted with an alkyl group having 1 to 9 carbon atoms and m denotes a number from 65 to 100;

Water dispersion for ink jet recording

A water-based ink comprising an aqueous dispersion of polymer particles made of a water-insoluble vinyl polymer containing a colorant, wherein the water-insoluble vinyl polymer is prepared by polymerizing a monomer composition comprising a specific monomer A such as a monomer A1 represented by the formula (I): wherein Ris hydrogen or methyl, Ris hydrogen, alkyl or alkylphenyl, and n is 1 to 30; a monomer having a salt-forming group; and a monomer copolymerizable with the monomer A and the monomer having a salt-forming group. The water-based ink can be suitably used as a water-based ink for inkjet recording and the like.

Water-based ink

There are provided a water dispersion for ink-jet printing comprising colorant-containing water-insoluble graft polymer particles in which the water-insoluble graft polymer contains a main chain which is a polymer chain containing a constitutional unit derived from a salt-forming group-containing monomer (a) and a constitutional unit derived from an aromatic ring-containing (meth)acrylate monomer (b), and a side chain which is a polymer chain containing a constitutional unit derived from a hydrophobic monomer (c); a water-based ink for ink-jet printing using the water dispersion; and an ink-jet printing method using the water-based ink. In accordance with the present invention, printed images or characters formed on a coated paper are excellent in gloss, image clarity and image clarity property including both of the image clarity and the gloss, and printed images or characters formed on an ordinary paper exhibit a high print density.

An ink set comprising at least one anionic chromatic colored ink and at least one cationic chromatic colored ink; and a recording process comprising the step of printing with an ink set comprising at least one anionic chromatic colored ink and at least one cationic chromatic colored ink. The ink set can be suitably used for a printer for inkjet recording or the like.

Ink set

A water-based ink for inkjet printing comprising a water dispersion of vinyl polymer particles prepared by containing a pigment in a vinyl polymer prepared by copolymerizing a monomer mixture comprising (a) a salt-forming group-containing monomer, (b) a macromer, and (c) a monomer copolymerizable with the salt-forming group-containing monomer and the macromer; and a process for preparing a water-based ink for inkjet printing comprising a water dispersion of vinyl polymer particles prepared by containing a pigment in a vinyl polymer, comprising dissolving in an organic solvent a vinyl polymer prepared by copolymerizing a monomer mixture comprising (a) a salt-forming group-containing monomer, (b) a macromer, and (c) a monomer copolymerizable with the salt-forming group-containing monomer and the macromer; adding a pigment to the resulting solution; pre-kneading the mixture; thereafter adding a neutralizing agent and water and kneading the mixture, to give an oil-in-water dispersion; and distilling off the organic solvent from the resulting kneaded product.

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Wakayama, Japan

Isao Tsuru