DIPOLE IMAGING USING WHITE DOT SCREENS
Original Publication Date: 1983-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
In order to utilize dipole marking particles in the development system of an electrophotographic printing machine, the latent image must be spacially modu-lated to obtain solid area coverage. A method of obtaining spacial modulation in positive to positive copying is to expose the photoconductive surface to an optical screen pattern before or after image exposure. Modulation may also be achieved by placing an opaque white dot screen on the platen of the printing machine. The original document being reproduced is then positioned on the dot screen. The charged photoconductive surface is exposed to the white dot screen and original simultaneously creating a modulated latent image. The latent image is modulated in the light absorbing areas only. This approach eliminates the requirement for using a screen in the optical system and increases exposure latitude over the pre and post screen exposure process.