| 摘要 |
PROBLEM TO BE SOLVED: To suppress the adhesion of a carrier to an image bearing member, reduction in density at the rear end of a solid image, reduction in image density when a developer is used for a long period of time, and the occurrence of a flaw in the surface layer of an image bearing member, and to improve dot reproducibility of an electrostatic latent image. SOLUTION: A two-component developer containing a magnetic carrier and a toner is disclosed, characterized in that: the magnetic carrier contains resin-containing magnetic particles containing a resin in pores of porous magnetic core particles; when the packed bulk density and the true density of the porous magnetic core particles are represented by ρ1 (g/cm<SP>3</SP>) and ρ2 (g/cm<SP>3</SP>), respectively, ρ1 is 0.80 or more and 2.40 or less and a ratio ρ1/ρ2 is 0.20 or more and0.42 or less; the porous magnetic core particles have a specific resistance of 1.0×10<SP>3</SP>Ω cm or more and 5.0×10<SP>7</SP>Ω cm or less; when a 50% particle diameter (D50) on a volume distribution basis is represented by D50, and the average breaking strength of the magnetic carrier having a particle diameter of D50-5 μm or more and D50+5 μm or less and the average breaking strength of the magnetic carrier having a particle diameter of 10 μm or more and less than 20 μm are represented by P1 (MPa) and P2 (MPa), respectively, P1 is set to 20 or more and 100 or less and P2/P1 is set to 0.50 or more and 1.10 or less; the toner comprises: toner particles containing at least a binder resin and wax; and the toner shows a toner surface tension constant of 3.0×10<SP>-6</SP>kN/m or more and 1.0×10<SP>-4</SP>kN/m or less in a 45 vol% aqueous solution of methanol measured by a capillary suction time method. COPYRIGHT: (C)2009,JPO&INPIT |
