US 7,514,193 B2
Developing toner for electrostatic latent images, imaging forming method and image forming apparatus
Hitoshi Nagahama, Uji (Japan); Tatsuo Imafuku, Nara (Japan); Takahiro Bito, Nara (Japan); Tenjiku Eiji, Nara (Japan); Takeshi Satoh, Yamatokoriyama (Japan); and Ohkawa Takeshi, Yamatokoriyama (Japan)
Assigned to Sharp Kabushiki Kaisha, Osaka (Japan)
Filed on Mar. 28, 2005, as Appl. No. 11/90,001.
Claims priority of application No. P2004-107506 (JP), filed on Mar. 31, 2004.
Prior Publication US 2005/0221214 A1, Oct. 06, 2005
Int. Cl. G03G 9/087 (2006.01)
U.S. Cl. 430—108.1  [430/108.7; 430/109.4] 6 Claims
 
1. A developing toner for electrostatic latent images comprising:
coloring resin particles containing a binder resin and carbon black; and
hydrophobic fluidizing particles deposited on surfaces of the coloring resin particles, the binder resin containing a polyester resin, a polyalkylene selected from the group consisting of a paraffin wax, an oxidized polyethylene wax, a polypropylene wax, a polybutene wax, an ethylene-propylene copolymer wax, an ethylene-butene copolymer wax, and a non-oxidized polypropylene; a polyolefin dispersant and a non-oxidized polyethylene wax, in which
the polyolefin dispersant is a polyolefin dispersant selected from
a polyolefin resin having a side chain of a styrenic polymer chain or styrene (meth)acrylic polymer,
wherein the amount of carbon black is 10 to 20 parts by weight based on 100 parts by weight of a polyester resin,
the amount of the hydrophobic fluidizing particles having a specific surface area of from 110 to 200 m2/g, are from 1.2 to 2.8 parts by weight based on 100 parts by weight of the coloring resin particles, and
a time constant τ of the toner being from 135 to 220 msec,
wherein the polyester resin consists of an unsaturated polyester resin which is synthesized from raw materials consisting of a polybasic acid and a polyhydric alcohol under the presence of a catalyst in an organic solvent, the polyester resin having an acid value of from 20 to 25 mg KOH/g and a hydroxyl value of from 11 to 17 mg KOH/g.