Abstract An electrophotographic reversal developing process where a charged electrophotographic element exposed to an optically negative image on an image bearing member where the area of the negative image is not over 10 percent of the area of the image bearing member. The electrophotographic element is next disposed with respect to a developing electrode which is completely electrically insulated from its surroundings to thereby induce on said electrode a potential which causes an electric field to occur at the image portions of the whole electrostatic latent image which is oppositely directed from that occurring at the background portion which corresponds to the area of maximum charge density. Next, toner particles having a charge of the same polarity as that of the background portion are introduced between the developing electrode and the electrophotographic element to develop the image portions.
The electrophotographic reversal developing process as set forth in claim 1 wherein said development is conducted in a liquid developer having toner particles dispersed in an insulating carrier liquid.
Claim 2
Dependent Claim
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The electrophotographic reversal developing process as set forth in claim 2 wherein said liquid development occurs in a metallic developing vat where the bottom of said metallic vat is utilized as the developing electrode.
Claim 3
Dependent Claim
36 words
The electrophotographic reversal developing process as set forth in claim 2 wherein said liquid development occurs in a developing vat composed of an insulating material having said developing electrode disposed at the bottom of the vat.
Claim 4
Dependent Claim
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The electrophotographic reversal developing process as set forth in claim 1 wherein said development step includes a powder cloud developing step.
Claim 5
Dependent Claim
38 words
The electrophotographic reversal developing process as set forth in claim 1 wherein said conductivE support is insulated from the developing electrode by covering the four sides of the electrophotographic element including said conductive support with an insulating material.
Claim 6
Dependent Claim
53 words
The electrophotographic reversal developing process as set forth in claim 1 wherein said conductive support is insulated from the developing electrode by inserting said conductive layer between an insulating support and the photoconductive insulating layer, the area of said conductive layer being smaller than that of the insulating support and the photoconductive layer.
Claim 7
Dependent Claim
27 words
The electrophotographic reversal developing process as set forth in claim 1 wherein the cross section or edge of the electrophotographic element is coated with an insulating material.