Toner containing particulate magnetic materials
AssigneeKao Corporation
InventorsMitsuhiro Sasaki, Koji Akiyama
Life of this patent
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Abstract
A toner for developing an electrostatic latent image which includes at least particulate magnetic materials and a binder resin has no particulate magnetic materials on the surface of the toner. In the toner, wherein A and b.sub.min satisfy the relationship: b.sub.min /A>0.02, where A represents an average particle diameter of the toner, and b.sub.min represents a minimum distance between a particulate magnetic material located at a position closest to the surface of the toner and the toner surface.
Claims12
A toner for developing an electrostatic latent image, comprising at least particulate magnetic materials and a binder resin, the toner having no particulate magnetic materials on the surface of the toner, wherein A and b.sub.min satisfy the relationship:
- b.sub.min /A>0.02,
- where A represents an average particle diameter of the toner, and b.sub.min represents a minimum distance between a particulate magnetic material located at a position closest to the surface of the toner and the toner surface, and wherein said toner is produced by the method comprising the steps of:
- (a) dissolving a shell-forming resin in a mixture comprising a core material-constituting monomer, particulate magnetic materials, and other additives to give a polymerizable composition;
- (b) dispersing the polymerizable composition obtained in step (a) in an aqueous dispersant, and localizing the shell-forming resin on the surface of droplets of a core-constituting material;
- and
- (c) polymerizing the polymerizable composition obtained in step (b) to form a core material covered with a shell.
A toner for developing an electrostatic latent image, comprising at least particulate magnetic materials and a binder resin, the toner having no particulate magnetic materials on the surface of the toner, wherein A and b.sub.min satisfy the relationship:
- b.sub.min /A>0.02,
- where A represents an average particle diameter of the toner, and b.sub.min represents a minimum distance between a particulate magnetic material located at a position closest to the surface of the toner and the toner surface, and wherein said toner is produced by the method comprising:
- adding a polymer or oligomer having a hydrophilic group and being soluble in a radical polymerization monomer to a mixture comprising particulate magnetic materials and the radical polymerization monomers, to give a polymerizable composition;
- and
- polymerizing the polymerizable composition by suspension polymerization.
A toner for developing an electrostatic latent image, comprising at least particulate magnetic materials and a binder resin, the toner having no particulate magnetic materials on the surface of the toner, wherein A and b.sub.min satisfy the relationship:
- b.sub.min /A>0.02,
- where A represents an average particle diameter of the toner, and b.sub.min represents a minimum distance between a particulate magnetic material located at a position closest to the surface of the toner and the toner surface, and wherein said toner is produced by the method comprising the steps of:
- (a) dissolving a shell-forming resin in a mixture comprising a core material-constituting monomer, particulate magnetic materials, and other additives to give a polymerizable composition;
- (b) dispersing the polymerizable composition obtained in step (a) in an aqueous dispersant, and localizing the shell-forming resin on the surface of droplets of a core-constituting material;
- (c) polymerizing the polymerizable composition obtained in step (b) to form precursor particles in which a core material is covered with a shell;
- (d) adding at least a vinyl polymerizable monomer and an initiator for vinyl polymerization to an aqueous suspension of the precursor particles obtained in step (c) to absorb them into the precursor particles;
- and
- (e) polymerizing the monomer components in the precursor particles.
Dependencies are inferred from the claim text.