Patent ID: 6344302
Filing Date: 2002-02-05
Classification: G03G

Abstract:
A developer for developing an electrostatic latent image comprising:toner particles comprising a colorant and a binder resin, said toner particles having a volume-average particle size of 5 to 10 &mgr;m; a first exterior additive comprising a hydrophobic anatase titanium oxide powder; and a second exterior additive comprising a silica powder; said developer satisfying following relationships: S1>S2,&NewLine;&it;400<(S12+S22)&leq;1300,&NewLine;&it;500&leq;S1&leq;1000,â€ƒ500&lE;S1&lE;1000, wherein S1 (m2) denotes total specific surface area of the first additive per 1 kg of the toner particles and S2 (m2) denotes that of the second additive, wherein said total specific surface areas S1 and S2 are represented by following formulas:S1=A1Â·B1 S2=A2Â·B2 wherein A1 (m2/g) denotes BET specific surface area of the first additive and is in the range of 70 to 200 m2/g, A2 (m2/g) denotes BET specific surface area of the second additive and is in the range of 50 to 300 m2/g, B1 (g) denotes content of the first additive per 1 kg of the toner particles, and B2 (g) denotes content of the second additive per 1 kg of the toner particles;said developer having improved flow characteristics when the first and second exterior additives are added to the toner particles.