Developer material with poly(p-xylylene) coated carrier

Claim 2

An electrostatographic developer mixture comprising finely-divided toner particles electrostatically clinging to the surface of carrier particles having an average particle size of between about 1 micron and about 1,000 microns, said carrier particles comprising a core surrounded with a thin outer coating comprising a substituted and/or unsubstituted poly(p-xylylene) polymer, said developer mixture being characterized as possessing triboelectric properties suitable for reversal development of positively charged electrostatic latent images.

Claim 3

An electrostatographic developer mixture according to claim 1 wherein said poly(p-xylylene) polymer is a homopolymer.

Claim 4

An electrostatographic developer mixture according to claim 1 wherein said poly(p-xylylene) polymer is a copolymer.

Claim 5

An electrostatographic developer mixture according to claim 1 wherein said thin outer coating is from between about 50 Angstroms and about 5 microns in thickness.

Claim 6

An electrostatographic developer mixture according to claim 1 wherein said core comprises a metal.

Claim 7

An electrostatographic developer mixture according to claim 5 wherein said metal comprises steel.

Claim 8

An electrostatographic developer mixture according to claim 1 wherein said poly(p-xylylene) contains repeating units of the structures ##SPC5## wherein R and R' are nuclear substituents selected from the group consisting of alkyl, aryl, alkenyl, amino, cyano, carboxyl, alkoxy, hydroxy alkyl, carbaloxy, hydroxyl, nitro, and halogen groups which may be the same or different, and x and y are each integers from 1 to 4, inclusive.

Claim 9

An electrostatographic developer mixture according to claim 7 wherein x and y are the same and R and R' are the same and said poly(p-xylylene) is a homopolymer having the structure: ##SPC6##

Claim 10

An electrostatographic developer mixture according to claim 7 wherein R and R' and/or x and y are different and said poly(p-xylylene) is a copolymer having the general structure: ##SPC7##

Claim 11

An electrostatographic developer mixture comprising finely-divided toner particles electrostatically clinging to the surface of carrier particles having an average particle size of between about 1 micron and about 1,000 microns, said carrier particles comprising a core having a first layer of a substituted silicon compound containing an ethylenically unsaturated group bonded to the silicon of the silicon compound by a carbon to silicon bond and at least one hydrolyzable group attached directly to the silicon of the silicon compound, and a second outer layer comprising a substituted and/or unsubstituted poly(p-xylylene) polymer, said developer mixture being characterized as possessing triboelectric properties suitable for reversal development of positively charged electrostatic latent images.

Claim 12

An electrostatographic developer mixture comprising finely-divided toner particles electrostatically clinging to the surface of carrier particles having an average particle size of between about 1 micron and about 1,000 microns, said carrier particles comprising a core having a first layer of a substituted silicon compound containing an ethylenically unsaturated group bonded to the silicon of the silicon compound by a carbon to silicon bond and at least one hydrolyzable group attached directly to the silicon of the silicon compound, and a second outer layer comprising a substituted and/or unsubstituted poly(p-xylylene) polymer, said developer mixture being characterized as possessing triboelectric properties suitable for reversal development of positively charged electrostatic latent images.

Claim 13

An electrostatographic developer mixture according to claim 10 wherein said silicon compound is gammamethacryloxy-propyltrimethoxy silane.