| 摘要 |
PURPOSE:To widen the permissible range of a toner concn. and to obtain a toner which is made longer in life and has excellent frictional electrostatic chargeability by combining the toner having dyes at a high concn. on toner particle surfaces in a specific concn. range with a ferrite carrier. CONSTITUTION:''C.I. Solvent Black(R)'' or the like is preferably used as a positive charge controlling agent and a complex azo dye contg. Cr, Fe and Co and having alcohol solubility is used as a negative charge controlling agent. The material formed by mixing such dyes together with resin powder and pigment by a blender which does not act shearing force such as cubic blender or V-type blender is melted and kneaded by a twin-screw extruder, etc. Such kneaded material is pulverized and screened after cooling by which the toner having the dye on the particle surface part at 4.0X10<-3>-9.0X10<-3>g/g surface concn. is obtd. Such toner (called electrodevelopable toner in this application) is combined with the ferrite carrier. The two-component developer which has the wide permissible range of the toner concn., does not require concn. adjustment at high frequencies, has good frictional electrostatic chargeability, is substantially free from fogging, brush marks, etc. and provides an excellent image is thus obtd. |
