| 摘要 |
PURPOSE:To obtain an always stable high quality image by using a nonmagnetic toner contg. a specified fine silica powder treated with a specified silane coupling agent and feeding it in a thin layer in a specified gap formed between a toner carrying body and an electrostatic image bearing body. CONSTITUTION:A fine silica powder, such as ''Aerosil 130'', etc., made by Nippon Aerosil KK, produced by vapor phase oxidation of silicon halide is treated and stabilized with a silane coupling agent represented by formula I (R is alkoxy or Cl; m is 1-3; Y is an N-contg. unsatd. heterocyclic compd. or its deriv.; and n is 3-1.), such as one represented by formula II, is added to an insulating nonmagnetic toner to attach the fine silica powder to the surface of each toner particle. This toner thickness is maintained smaller than the distance between an electrostatic image bearing body 1 and a toner carrying body 2 in a developing region and AC and DC bias voltage are impressed between the body 1 and body 2 from a power supply 6 to develop the electrostatic latent image. As a result, a high quality image is obtained throughout the range of low temp. and low humidity to high temp. and high humidity. |
