| 摘要 |
PURPOSE:To obtain a stable image even in the environment ranging from low temp. and low humidity to high temp. and high humidity by using an insulating nonmagnetic toner contg. guanamine, its deriv., or their condensates as a positive electrostatic charge controller. CONSTITUTION:An insulating nonmagnetic toner 5 contains guanamine or its deriv. or a condensate of them and formaldehyde or the like as a positive chargeability controller in a binder resin. An electrostatic latent image formed on an image bearing drum 1 is developed by keeping a layer thickness of the toner 5 smaller than the distance between the drum 1 and a toner 5 carrying sleeve 2 in a developing region, and AC and/or DC bias voltage is impressed between the drum 1 and the sleeve 2 from a power supply 6. As a result, an image of stable quality can be obtained under all the environments for a long term. An always stable image is obtained likewise by using a nonmagnetic one-component type toner or a 2-component type developer consisting of this toner and a magnetic carrier. |
