PURPOSE: To obtain a grey scale single component non-magnetic developing system for electrophotography using AC and DC bias voltages impressed on a developing roller and a single component non-magnetic developer imparted by a supplying roller so as to develop an electrostatic latent image on a photoconductor.
CONSTITUTION: The developer is constituted of the mixture 45 of toner particles 46 electrified to a single polarity and transparent beads 47 electrified to an opposite polarity, and is triboelectrostatically and collectively more electrified by an alternating electric field between two rollers 13 and 14 than by frictional contact with a device surface. The roller 14 imparts the electrified mixture to the roller 13, and develops the latent image 21 to have image density 22 decided by a DC bias value. The DC bias 54 of the supplying roller gives potential gradient in relation to the DC bias 50 of the developing roller, and drives the collectively electrified mixture to the developing roller. A doctor blade 15 smoothes toner 44 on the roller 13 to have selected thickness. The roller 13 has a semiconductor surface layer 27 which is not coated, or which is non- conductively coated.
JIYOSEFU EDOWAADO GASU
UIRIAMU BAANAADO BURIIRANDO
TOOMASU AASAA JIYADOUIN
