| 摘要 |
PURPOSE:To obtain a high image density which is stable from an initial period without fogging and splashing and to reproduce the stable image which is not affected by age and the change of temp. and humidity by incorporating magnetic toner, pulverous positive chargeability silicic acid powder and the oxide powder of the element belonging to the group IVa of periodic table into a magnetic developer. CONSTITUTION:This positive chargeability magnetic developer consists of the magnetic toner, pulverous positive chargeability silicic acid powder and oxide powder of the elements belonging to the group IVa of periodic table. The pulverous silicic powder is effective when said powder is used at 0.01-20pts.wt. per 100pts.wt. toner. Said powder exhibits the positive electrostatic chargeability having excellent stability when the powder is added to the toner more particularly preferably at 0.05-5pts.wt. The oxide of the group IVa elements which can be used is exemplified by titanium oxide, zirconium oxide and hafnium oxide. These metallic oxides are incorporated into the developer at 0.1-20wt%, more preferably 0.2-5wt% per 100pts.wt. toner. The grain size thereof is preferably <=5mu, more preferably in a 0.01-3mu range. |
