Imaging system for electrostatic reproduction machines
AssigneeXerox Corporation
InventorRobert P. Rippstein
Life of this patent
Estimating the term…
Abstract
Electrostatic type copying apparatus incorporating an arrangement to control the electrostatic developing field to enhance reproduction of half-tone images. The control arrangement has an electrostatic field effect neutralizer effective to release neutralizing electrons in response to image charge conditions. Grid control and/or housing bias are employed to regulate the discharge and quantity of ions available.
Claims6
In an electrostatic reproduction machine having a photoconductive member, the combination of:
- charging means to charge said photoconductive member in preparation of imaging
- exposure means to expose said charged photoconductive member to selectively discharge said photoconductive member and form a latent electrostatic image on said photoconductive member in accordance with the original being reproduced;
- means forming a reservoir of charged ions, said ions being charged opposite from said photoconductive member charge whereby charges left on said photoconductive member and comprising said latent electrostatic image tend to attract oppositely charged ions from said reservoir in accordance with the charge level of the charges left on said photoconductive member and thereby reduce peak charge levels remaining on said photoconductive member;
- and
- control gate means for regulating the flow of ions from said reservoir to said photoconductive member.
In an electrostatic reproduction machine having a photoconductive member on which latent electrostatic images on the original being copied are generated, the combination of
- a charge corotron for charging said photoconductive member to a relatively high voltage of predetermined polarity in preparation for imaging
- means to expose said charged photoconductive member to the original being copied whereby to form on said photoconductive member a latent electrostatic image of said original, said latent electrostatic image being defined by charges of various voltage magnitude
- means adapted to reduce areas of higher charge and level off said latent image defining charges to enhance solid area coverage, said charge control means including a source of ions charged to a polarity opposite said photoconductive member predetermined polarity downstream of said exposure means, a sump for storing said ions, and valve means for releasing said charged ions from said sump at a present rate, charged ions released from said sump being drawn to said photoconductive member to effect a disproportionate reduction of higher charge areas and enhance reproduction of image solid areas.
Dependencies are inferred from the claim text.