coated photoconductive paper 16 the paper 16 can be any standard coated xerographic paper but is preferably a paper utilizing zinc oxide as the photoconductive material such as that sold by the nashua corporation of nashua new hampshire although the paper 16 is shown as a continuous sheet it will be understood that individual sheets of coated paper can also be used the apparatus 12 is organized into four sequential processing stations 18 20 22 and 24 the first station 18 charges the paper with a corona discharge device 26 that places a uniform high potential electrostatic charge on the paper once charged the paper advances to the exposure station 20 where the document to be copied is exposed to a conventional high intensity light source 28 and scanned using well known opical techniques to produce a latent electrostatic image pattern in the photoconductive coating that corresponds to the pattern of characters on the specimen document 14 in the non image areas struck by the light the photoconductive material has a decreased resistivity following the exposure which allows the charge to dissipate in the image areas the photoconductive material maintains its high dark resistivity and little or no charge leaks off the developing station 22 which is the subject of the present invention applies a toner material to the image bearing surface of the paper to render the latent electrostatic pattern visible the toner or developer material is in the form of finely divided particles that are polarized so as to be electrically of the opposite polarity to that of the electrostatic image pattern the toner material therefore is selectively attractive to and collects at the charged image areas in preference to the non image areas that.