| 摘要 |
PURPOSE:To obtain an electrostatic image developer capable of forming a good developed image without deteriorating fluidity of the developer even after forming numerous developed images for a long time, by adding toner particles, and silica particles having 2 kinds of specified structures. CONSTITUTION:The developer comprises conductive colored particles and the first silica particles in which an Si atom having an org. group (A) is combined with the Si atom on the surface of the particle by the medium of an O atom, and the second silica in which an Si atom having an org. group (B) is combined with the Si atom on the surface via an O atom, and said group (A) is in any case an organic group which has an aliphatic org. group or a hydrocarbon ring each having <=4C, and in which the total number of C is <=7, and said group (B) is an organic group which has at least one having >=5C, and the total is >=8C. As a result, the developer can form a good developed image without deteriorating fluidity after forming numerous developed images for a long time, and without impairing the surface of the electrostatic image bearing material. |
