Abstract: A nonaqueous ink composition contains a diketopyrrolopyrrole-based pigment and is suitable for use as a nonaqueous ink composition to be ejected by an ink-jet method. The nonaqueous ink composition includes a pigment, a pigment dispersant, an organic solvent, and a resin, wherein the pigment includes a pigment A represented by formula (1) and the content of the pigment dispersant is lower than the content of the pigment. (In formula (1), X1 to X10 each independently represent a hydrogen atom, a halogen atom, an optionally branched C1-C5 alkyl group, an aromatic hydrocarbon group in which the hydrogen atoms may have been replaced, a cyano group, a nitro group, an amino group, —OH, —COOH, —COO?M+, —SO3H, —SO3?M+, a phthalimide group in which the hydrogen atoms may have been replaced, a phthalimidomethyl group, or a heterocyclic compound, and M+ represents a cation.

Abstract: A non-aqueous ink composition which, even when containing a perinone-based pigment, can be suitably used as a non-aqueous ink composition that is ejected by an inkjet method. The non-aqueous ink composition ejected by an inkjet method contains a pigment, a pigment dispersant, an organic solvent, and a resin, wherein the pigment contains a pigment A represented by formula (1), and the content of the pigment dispersant is smaller than the content of the pigment. (In formula (1), X1-X12 each independently represent a hydrogen atom, a halogen atom, an optionally branched alkyl group having 1 to 5 carbon atoms, or an aromatic hydrocarbon group optionally substituted with a hydrogen atom, a cyano group, a nitro group, an amino group, —OH, —COOH, —COO—M+, —SO3H, —SO3?M+, a phthalimido group in which a hydrogen atom may be substituted, a phthalimidomethyl group, or a heterocyclic compound, and M+represents a cation.

Abstract: A horizontal centrifugal separator is configured such that a groove formed along a joint surface between an upper casing and a lower casing constituting the casing is outwardly bent near an opening of the casing, and that an elastic sealing member is disposed in the groove and an end portion thereof abuts against a sealing surface provided on a ring member which is provided so as to surround the outer circumference of the opening of the casing and is pressed against the casing. In this case, surface sealing is constituted by the end portion of the elastic sealing member and the sealing surface of the ring member. In this manner, the hermeticity can be improved without using a sealing member having a complicated structure.

Abstract: A horizontal centrifugal separator is provided in which the hermeticity of the casing can be improved by using sealing means having a simple structure. The horizontal centrifugal separator is configured such that a groove formed along a joint surface between an upper casing and a lower casing constituting the casing is outwardly bent near an opening of the casing, and that an elastic sealing member is disposed in the groove and an end portion thereof abuts against a sealing surface provided on a ring member which is provided so as to surround the outer circumference of the opening of the casing and is pressed against the casing. In this case, surface sealing is constituted by the end portion of the elastic sealing member and the sealing surface of the ring member. In this manner, the hermeticity can be improved without using a sealing member having a complicated structure.