Seiko Epson Corporation

Michio Nakamori

Yasunari Ikeda

Hirofumi Hokari

Shinichi Yamamoto

Shigeki Kawada

Hiroko Hayashi

Shinichi Naito

Kenji Kitada

Kenta Kikuchi

Hisashi Okamura

Seiji Kagami

Kazumasa Otsuki

A magnetic bead reagent contains: a magnetic bead containing a Fe-based metal soft magnetic particle and a silica film that has an average thickness of 20 nm or more and that covers the Fe-based metal soft magnetic particle; a surfactant; and a dispersion medium in which the magnetic bead is dispersed. The surfactant may be a nonionic surfactant.

Magnetic bead reagent

A magnetic bead contains: a magnetic metal powder; and a coating layer with which a particle surface of the magnetic metal powder is coated. When the magnetic bead is left to stand in a state of a dispersion obtained by dispersing the magnetic bead in water, a time until an initial absorbance of the dispersion attenuates to 80% of an absorbance when the standing is started is 90 seconds or longer.

Magnetic bead and magnetic bead dispersion

An aqueous ink jet composition of the present disclosure includes: at least one dye selected from the group consisting of C.I. Solvent Yellow 160:1, C.I. Disperse Yellow 82, and C.I. Disperse Yellow 184; a material A which is at least one compound selected from the group consisting of a compound represented by the following formula (1), a compound represented by the following formula (2), an ethylene oxide adduct of tristyrylphenol, a derivative of an ethylene oxide adduct of tristyrylphenol, a polyalkylene glycol, and a derivative of a polyalkylene glycol; and an anionic dispersant.

Aqueous ink jet composition

An aqueous ink jet composition contains: C.I. Disperse Red 364; a material A which is at least one compound selected from the group consisting of a compound represented by the following formula (1), a compound represented by the following formula (2), an ethylene oxide adduct of tristyrylphenol, a derivative of the ethylene oxide adduct of tristyrylphenol, a polyalkylene glycol, and a derivative of the polyalkylene glycol; and an anionic dispersant. 

An aqueous ink jet composition according to the present disclosure includes: C.I. Disperse Red 364 as a first component; a second component which is a dispersant having a chemical structure of at least one of a sulfo group and a salt thereof; and a third component having an indigo skeleton and a chemical structure of at least one of a sulfo group and a salt thereof.

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Matsumoto, Japan

Michio Nakamori