| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative charge type toner, which is excellent in chargeability, charge stand-up performance, and environmental stability, adaptable even to a toner replenishment type one-component developing system, and to cost reduction, and which ensures neither faulty following property to a solid area nor surface fog, and gives stable images over a prolonged period of time, and to provide a toner container using the same, a process cartridge, and an image forming apparatus. SOLUTION: The negative charge type toner comprises a toner base containing at least a binder resin, a colorant and a negative charge control agent, and an external additive and is used in a nonmagnetic one-component developing system, wherein the negative charge control agent comprises a negative charge control resin consisting of a copolymer having monomeric units of (i) a sulfonate-group-containing monomer, (ii) a phenylmaleimide substitution product monomer and/or a phenylitaconimide substitution product monomer substituted by a chlorine atom or a nitro group, and (iii) an acrylic ester monomer and/or a methacrylic ester monomer, and the external additive comprises at least (a) hydrophobic silica particles and (b) hydrophobic titanium oxide particles. COPYRIGHT: (C)2005,JPO&NCIPI
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