METHOD FOR INVERSE DEVELOPMENT

摘要

PURPOSE:To obtain many fine copies without the generation of fog and the change of density by using magnetic toner consisting of one component which is agitated in a magnetic field in the method to inversely develop an electrostatic latent image into a toner image by magnetic brush method. CONSTITUTION:After forming an electrostatic latent image on an electrophotographic receptor 4 obtained by forming a photoconductive layer 1 (e.g. a layer obtained by dispersing zinc oxide into a bonding agent) on a conductive supporting element 2, the latent image is developed into a toner image by magnetic toner 7 through a non-magnetic sleeve 8 (to which bias voltage having the same polarity as the surface potential of the photoreceptor 1 is applied) to be rotated relatively to a magnetic roll 10. For said toner, toner obtained by agitating (by using an insulated case 5 and an agitator 6) unmagnetized toner 3 (about <=35wt% of <=15mu grain size and about <=3wt% of <=10mu grain size) consisting of an adhering agent and magnetic powder for 5min-10hr at about 5-60 deg.C under about <=700 gausses of magnetic field generated by a coil 11 is used.