| 摘要 |
PURPOSE:To improve the flowability, electrostatic charge stability and durability by adding positive chargeable fine silica particles and oxide powder of group IVa elements to the developer. CONSTITUTION:This developer is prepd. by adding the positive chargeable fine silica particles (A) and the oxide powder of the group IVa elements (B) to the developer essentially consisting of a coated carrier and magnetic toner. The silica which is subjected to a surface treatment with an amino modified silicone compd. and has a prescribed triboelectrostatic charge quantity, average grain size and specific surface area can be used for the component A. Titanium oxide, zirconium oxide or halfnium oxide having a prescribed average particle size and specific surface area can be used for the component B. The flowability and electrostatic charge stability of the developer are thereby improved and the flawing of a photosensitive body by a magnetic brush is decreased and, therefore the images which are good even after long-term use or by a change in environmental conditions are obtd. |
