Method of protecting images

Claim 2

The method as described in claim 1 wherein the carrier liquid has a volume resistivity of greater than about 109 ohm.-cm. and a dielectric constant of less than about 3.

Claim 3

The method as described in claim 1 wherein the image-bearing member is an electrophotographic element comprised of a photoconductive layer carried on an electrically conductive support.

Claim 4

The method as described in claim 1 wherein the developed image is formed using a liquid developer comprised of colored marking particles contained in an electrically insulating liquid vehicle.

Claim 5

The method as described in claim 1 wherein the uniformly deposited transparent resin particles are heated to permanently fix said particles to the image-bearing member.

Claim 6

The method as described in claim 1 wherein the image-bearing member is comprised of an electrically insulating material having a separate electrically conductive backing in contact therewith.

Claim 7

The method as described in claim 1 wherein said dispersion of transparent charge-bearing particles in an electrically insulating carrier liquid comprises from about one-fourth to about 5 grams of said particles per liter of carrier liquid.

Claim 8

A microimage add-on process wherein a plurality of transparent protective coatings and at least one additional visible developed microimage are applied to an electrographic element having a visible, substantially unfixed, developed electrostatic microimage on one surface thereof and a contiguous electrically conductive backing associated with a surface of said element opposed to said one surface, said process comprising a. subjecting said member to a direct current electrical field established between said conducting backing and an external electrical source to create a potential difference between the conducting backing and the external source; b. applying a dispersion, comprising about one-fourth to about 5 grams of transparent charge-bearing resin particles admixed in each liter of a carrier liquid having a volume resistivity greater than about 109 ohm.-cm. and a dielectric constant less than about 3, to said microimage-bearing member while said element is under the influence of said field to obtain a uniform coating of said particles over the micro image-bearing surface of said element; c. removing said member from the influence of the external electrical source; d. drying exces carrier liquid from the element and permanently fixing said uniformly deposited transparent resin particles to said element; e. forming an additional visible, substantially unfixed, developed electrostatic microimage on the surface of said uniform coating; and f. repeating the cycle defined by steps (a) - (e) from 1 up to 10 more times with the proviso that in the last repetition of said cycle step (e) is omitted, whereby a series of visible, fixed, microimages superimposed one over the other are produced on the surface of the resultant electrographic element.

Claim 9

The method as described in claim 9 wherein the developed microimages are formed using a liquid developer composition comprising colored marking particles dispersed in an electrically insulating liquid vehicle.

Claim 10

The method as described in claim 9 wherein the developed microimages are formed using a liquid developer composition comprising colored marking particles dispersed in an electrically insulating liquid vehicle comprised of the same liquid as said carrier liquid.

Claim 11

The method as described in claim 9 wherein said element is an electrophotographic element comprised of an organic photoconductor-containing layer carried on an electrically conductive support.

Claim 12

The method as described in claim 9 wherein the external electrical source is a closely spaced electrode which is spaced about one-half to about 2 mm. from said image-bearing element and wherein the potential difference created between said electrode and said conducting backing is from about 800 to about 2,000 volts.

Claim 13

The method as described in claim 9 wherein said resin is selected from the group consisting of an alkyd resin, a phenol-formaldehyde resin, a methacrylate resin, a vinyl resin and mixtures thereof.

Claim 14

The method as described in claim 9 wherein said resin dispersion contains a heavy metal soap as a chrage control agent.

Claim 15

The method as described in claim 9 wherein the potential difference between said conducting backing and said external source is within a range of from about 200 to about 50,000 volts.

Claim 16

The method as described in claim 9 wherein the external electrical source is a corona charging needle which is spaced from about 0.8 cm. to about 4.0 cm. from said electrophotographic element and wherein the potential difference created between said needle and said conducting backing is from about 3,000 to about 12,000 volts.