DRY ELECTROPHOTOGRAPHIC TONER

Japanese Patent JP3877297

B2

PROBLEM TO BE SOLVED: To provide an electrophotographic toner which can prevent a filming even after a long-term continuous use and can keep stability for electrification and transportation and a high-quality output image when the toner is used for whichever a single-component or two-component development method.
SOLUTION: The toner essentially comprises a binder resin, a colorant, an electrification controlling agent and an additive. The binder resin is a polyester which contains no THF-insoluble component and has a component having ≤5×102 weight average molecular weight by ≤4 wt.% and the main peak by GPC in the region from 3×103 to 9×103. The electrification controlling agent is a resin which comprises (A) a sulfonate group-containing monomer, (B) an aromatic monomer having an electron withdrawing group and (C) a (meth)acrylate monomer, and moreover, may contain (D) an aromatic vinyl monomer, and the agent has 9.5 to 11.5 LogΩcm as the volume resistivity. The additive comprises hydrophobic silica and hydrophobic titanium oxide having 0.01 to 0.03 μm primary particle size, and the titanium oxide has 60 to 140 m2/g specific surface area.

Hiroyuki Fushimi
Osamu Uchinokura
Mitsuteru Kato

JP2002075460A

February 07, 2007

March 19, 2002

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株式会社リコー

G03G9/08; G03G9/097; G03G9/087; G03G15/08; (IPC1-7): G03G9/097; G03G9/08; G03G9/087; G03G15/08

JP11218965A
JP9171271A
JP2001305851A
JP2002082488A
JP2000352838A
JP830017A
JP2001206923A

Masami Sakai
Hidetake Komatsu
Norio Kagami

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