OPTICAL RESIDUAL IMAGE ERASURE
Original Publication Date: 1984-Feb-29
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
When making multi-color plots on dielectric-coated paper (as in Versatec's electro-graphic color plotter) residual electrostatic latent images from prior color image recording(s) cause objectionable color mixing during successive toning steps.
XEROX DISCLOSURE JOURNAL
OPTICAL RESIDUAL IMAGE ERASURE Proposed Gene F. Day Classification
U.S. C1. 346/157 Int. C1. Gold 15/06
When making multi-color plots on dielectric-coated paper (as in Versatec's electro- graphic color plotter) residual electrostatic latent images from prior color image recording(s) cause objectionable color mixing during successive toning steps.
It is suggested, in the present disclosure, that the normally undesirable character- istic of photoconductivity in the dielectric-coated paper could be utilized, and even enhanced to effectively erase the residual latent image after each toning step. By placing an erasing light source across the paper, the charge image could be dis- charged as the paper is returned for a subsequent color separation imaging step.
Presently, the dielectric-coated paper is a functional insulator exhibiting an ex- tremely small degree of photoconductive response. An intense (preferably UV) erase lamp could be used just after toning. For example, a mercury vapor lamp (such2as an uncoapd fluorycent tube) could expose the toned image about 0.1 J/cm or about 10 erg/cm of radiation. Alternatively, the radiation could be supplied from a flash lamp.
It is also possible to formulate a special paper coating to implement this idea. If dye sensitization is required in order to produce adequate photoresponse of the pigment in the coating, no visible paper coloring need result since the sensitizing dye need only be UV sensitive....