| 摘要 |
A liquid toner and an ink composition, which comprise a dispersion of copolymer resin particles composed of at least two different monomer components in a dispersion medium. The copolymer resin particles and the dispersion medium are related to each other such that the difference DELTA delta 1 between the solubility parameter value delta p1 of a homopolymer composed only of at least one monomer component in the copolymer resin and the solubility parameter value delta s1 of the dispersion medium is not smaller than 1.0, and that the difference DELTA delta 2 between the solubility parameter value delta p2 of a homopolymer composed only of at least one other monomer component and the solubility parameter value delta s1 of the dispersion medium is not larger than 1.0, and further that the difference DELTA between DELTA delta 1 and DELTA delta 2 ( DELTA delta 1- DELTA delta 2) is at least 0.5. Moreover, each copolymer resin particle comprises a nuclear portion which is insoluble in the dispersion medium, and an outer skin portion which wraps the nuclear portion, and which is soluble or swellable in the dispersion medium. The liquid toner is a dispersion of the copolymer resin particles in an electrically insulating dispersion medium. The liquid toner is free from sedimentation, aggregation or other problem even if the pigment content is increased, and hence excellent in dispersibility and free from gelation. The ink composition is a dispersion of the copolymer resin particles in a dispersion medium. Even if the pigment or other particle content is increased, sedimentation, aggregation or other problem will not occur. Thus, the ink composition exhibits excellent dispersibility and is free from gelation and superior in coatability.
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