Electrophotographic copying - using single component, electrically conducting toner particles with magnetisable core and resin carbon outer coating

摘要

In the transfer of a toner powder image consisting of electrically conducting particles from a photo-receptor surface to a transfer material, in an electro photographic copier, the photoconducting layer of the photoreceptor surface is made electrically conducting by image-wise exposure to an adjacent light source. A potential is applied across the photoconducting layer in such a way that a charge is formed on the transfer material while a charge of opposite sign is induced on the layer. The charge on the photoconducting layer migrates onto the conducting toner particles. Coulomb forces are exerted on the charges on the toner particles by the charge on the transfer material and that in the photoconducting layer so that the toner particles are transferred electrostically to the transfer material. The electrically conducting toner powder pref. consists of fine particles of magnetisable material coated with a resin and carbon. The method enables a single component electrically conducting toner to be used in a practicable photocopier.