JPS5543561A - Two color developing method - Google Patents

Abstract

PURPOSE: To obtain a clear image with sufficient charge amount at a short time, by mixing one-pack high resistance magnetic toner of different two colors being charged in reverse polarity each other, supplying the mixture on the developing roller, and defining the toner quantity by means of a doctor on the roller, and further charging.

CONSTITUTION: As a developer 11, for instance, an equal mixture of a black and a red one-pack high resistance magnetic toners is used. Both toners are put into a hopper 12, and mixed and agitated by an agitating member 13 provided inside, and are frictionally charged in reverse polarity each other. For the purpose of this reverse polarity charging, the toners having different priority of frictional charging sevies are used, and the material for the agitating member 13 should be situated in the middle between the two toners with respect to the priority of frictional charging system. The toners supplied on the developing roller 14 from the hopper 12 are defined in the quantity at the tip of the doctor 16 attached to the side wall of the hopper 12 by way of an insulating plate 15, and the toners are further charged frictionally.

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