Electrostatic image developing toner with high dielectric material
AssigneeKao Corporation
InventorsShoji Ohtani, Kazunari Takemura, Yukiya Sato, Rikio Tsushima
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Abstract
A developing toner composition is effectively prepared by dispersing in a polymerizable monomer a charge controller, a coloring agent and a highly dielectric material having a dielectric constant of at least 10 at room temperature and a volume resistivity of at least 1.times.10.sup.10 ohm.cm and dispersion-polymerizing the resulting dispersion in an aqueous medium in the presence of a dispersion stabilizer to obtain resin particles.
Claims20
A developing toner composition for an electrostatically charged image, which comprises
- (i) a coloring agent, and
- (ii) a resin binder comprising a polymer, a charge controller and an effective amount of a highly dielectric material for maintaining suspension stability which is selected from the group consisting of a titanate, a niobate, a tartrate, a zirconate, a stannate, potassium dihydrogen phosphate and sodium nitrate, wherein said highly dielectric material has a dielectric constant of at least 10 at room temperature and a volume resistivity of at least 1.times.10.sup.10 ohm.cm, said toner composition having a surface substantially free of said dielectric material.
A process for preparing a developing toner composition for an electrostatically charged image, which comprises:
- (i) dispersing in a polymerizable monomer a charge controller, a coloring agent and an effective amount of a highly dielectric material for maintaining suspension stability during polymerization which is selected from the group consisting of a titanate, a noibate, a tartrate, a zicronate and a stannate, wherein said highly dielectric material having a dielectric constant of at least 10 at room temperature and having a volume resistivity of at least 1.times.10.sup.10 ohm.cm, and
- (ii) dispersion-polymerizing the resulting dispersion in an aqueous medium in the presence of a dispersion stabilizer to obtain resin particles.
A developing toner composition for an electrostatically charged image, which comprises:
- (i) a coloring agent, and
- (ii) resin binder comprising a polymer, a charge controller and an effective amount of a highly dielectric material for maintaining suspension stability during polymerization which is selected from the group consisting of a titanate, a niobate, a tartrate, a zirconate and a stannate, wherein said highly dielectric material has a dielectric constant of at least 10 at room temperature and a volume resistivity of at least 1.times.10.sup.10 ohm.cm, said devleoping toner composition being prepared by the steps which comprise:
- (a) dispersing in a polymerizing monomer a charge controller, said coloring agent and said highly dielectric material having a dielectric constant of at least 10 at room temperature and having a volume resistivity of at least 1.times.10.sup.10 ohm.cm, and
- (b) dispersion-polymerizing the resulting dispersion in an aqueous medium in the presence of a dispersion stabilizer to obtain resin particles.
Dependencies are inferred from the claim text.