| 摘要 |
PROBLEM TO BE SOLVED: To supply an electrophotographic toner so excellent in durability as to ensure less carrier spent and satisfactory image density even after long-term use. SOLUTION: The electrophotographic toner contains at least a binder resin, a colorant, a release agent and inorganic fine particles. The toner is mixed with a carrier comprising magnetic particles to obtain a two-component developer for electrostatic image development having a toner concentration of 8 wt.%. The charge quantity distribution of the toner in the initial developer is determined by an increment method with a blow off device in an environment at 23°C and 55% RH and a charge quantity distribution function chart is obtained using Poisson's function. In the diagram, a peak is present in a range of 20-40μC/g in absolute value and a total of distribution function values of≤14μC/g is≤0.8 (mg/10 g). At least titania is contained as the inorganic fine particles and a rate of free titania released from the toner base determined by a ultrasonic vibration method is 5-22%. COPYRIGHT: (C)2007,JPO&INPIT |
