microfield donors used in a xerographic process and the methods for manufacturing them . the donor is provided with means for establishing a plurality of electrostatic microfields on the donor surface to attract and hold toner particles so they can be transported to a developing station . the polarity of the established microfields are continuously reversed to alternately repel and attract toner particles to the doner surface during their transportation in order to agitate the toner particles to prevent agglomeration of the particles from forming and to effect nullification of the microfield attracting the particles adjacent a photoconductor to form a high density image free of background deposits in uncharged area of the photoconductive surface .