Reactive developer for electrophotography

Claim 1

A DEVELOPER FOR ELECTROPHOTOGRAPHY COMPRISING AN INSULATING CARRIER LIQUID HAVING AN ELECTRICAL RESISTIVITY OF AT LEASST 10**10 OHM-CENTIMETER AND DEVELOPER PARTICLES SUSPENDED IIN SAID CARRIER LIQUID AND BEING ELECTRICALLY CONDUCTIVE SO AS TO BE MOVABLE IN THE CARRIER LIQUID UNDER THE INFLUENCE OF AN ELECTRICAL FIELD, SAID DEVELOPER PARTICLES BEING REACTIVELY PRODUCED IN SITU IN SAID CARRIER LIQUID AND BEING CONSTITUTED BY THE REACTION PRODUCT OF AT LEAST TWO SUBSTANCES BOTH SOLUBLE IN SAID CARRIER LIQUID, ONE BEING A SUBSTANCE WHICH IS ELECTRICALLY INSULATIVE RELATIVE TO THE CARRIER LIQUID AND WHICH DOES NOT REDUCE THE ELECTRICAL RESISTIVITY OF THE CARRIER LIQUID WHEN DISSOLVED THEREIN, THE OTHER SUBSTANCE BEING A SUBSTANCE WHICH IS ELECTRICALLY CONDUCTIVE RELATIVE TO THE CARRIER LIQUID AND REDUCES THE ELECTRICAL RESISTIVITY OF THE CARRIER WHEN DISSOLVED THEREIN, SAID SUBSTANCES FORMING, WHEN IN DISSOLVED STATE IN SAID CARRIER LIQUID SAID CONDUCTIVE DEVELOPER PARTICLES, THE RELATIVE QUANTITIES OF SAID TWO SUBSTANCES BEING SO SELECTED THAT THERE IS NO SURPLUS OF THE RELATIVELY CONDUCTIVE SUBSTANCE AFTER REACTION IN THE CARRIER LIQUID TO INSURE THAT THE RESISTIVETY OF THE CARRIER LIQUID IS NOT LOWERED IN ITS INSULATING VALUE, SAID DEVELOPER PARTICLES BY VIRTURE OF BEING FORMED IN SAID CARRIER LIQUID BEING SHIELDED AGAINST OXIDATION AND BEING HELD IN SAID LIQUID UNTIL USED AS A DEVELOPER, SAID CARRIER LIQUID BEING A HYDROCARBON LIQUID, SAID SUBSTANCE OF GREATER INSULATING VALUE BEING SELECTED FROM THE GROUP CONSISTING OF: QUINALIZARIN ANTHRANILIC ACID, ALIZARIN, HYDROQUINONE, CHLORANIL, SYMDIPHENYLCARBAZIDE, DIPHENYLTHIOCARBAZIDE, 2-FUROIC ACID, TETRACHLOROPHTHALIC ANHYDRIDE, FUMARIC, AND NAPHTHALENE -2-SULPHONIC ACCID, CITRAL, CINNOMOLDEHYDE AND DIPHENYLIAMINE, SAID SUBSTANCE WHICH IS MORE CONDUCTIVE BEING SELECTED FROM THE GROUP CONSISTING OF: COBALT OCTOATE, THE OCOATES AND NAPHTHENATES OF ZINC, LEAD, MANGANESE, COPPER, ZIRCONIUM, IRON AND CHROMIUM, COPPER NONYL PHTHALATE AND FERRIC CHLORIDE.

Claim 8

A method for making a developer for electrophotography of the type comprising an insulating carrier liquid having conductive developer particles suspended therein capable of being moved in an electrical field, said method comprising reactively producing the developer particles by placing into a carrier liquid having an electrical resistivity in excess of 1010 ohm. centimeter, at least two substances both soluble in the said carrier liquid, one being a substance which is an insulator relative to the carrier liquid and which does not reduce the electrical resistivity of the carrier liquid when dissolved therein, the other being a substance which is a conductor in relation to the carrier liquid and which reduces the electrical resistivity of the carrier liquid when dissolved therein, said substances being so selected to form, when in a dissolved state in the carrier liquid, another solution which precipitates to form said developer particles, said substances being selected in quantity such that by reaction therebetween there is no surplus of the conductive substance after reaction in the carrier liquid whereby the resistivity of the carrier liquid in its final state is not lowered in insulating value, and whereby the developer particles are themselves formed in the liquid to be shielded against oxidation and are held in such liquid until used as a developer, said carrier liquid being a hydrocarbon liquid, and said insulating substances being selected from the group consisting of: Quinalizarin, anthranilic acid, Alizarin, Hydroquinone, Chloranil, sym-diphenylcarbazide, diphenylthiocarbazide, 2-Furoic Acid, Tetrachlorophthalic anhydride, fumaric acid, Naphthalene-2-Sulphonic Acid, Citral, Cinnomoldehyde and Diphenyliamine, said conductive substance being selected from the group consisting of: cobalt octoate, the octoates and naphthenates of zinc, lead, manganese, copper, zirconium, iron and chromium, copper nonyl phthalate and ferric chloride.

Claim 9

A method for making a developer for electrophotography of the type comprising an insulating carrier liquid having conductive developer particles suspended therein capable of being moved in an electrical field, said method comprising reactively producing the developer particles by placing into a carrier liquid having an electrical resistivity in excess of 1010 ohm. centimeter, at least two substances both soluble in the said carrier liquid, one being a substance which is an insulator relative to the carrier liquid and which does not reduce the electrical resistivity of the carrier liquid when dissolved therein, the other being a substance which is a conductor in relation to the carrier liquid and which reduces the electrical resistivity of the carrier liquid when dissolved therein, said substances being so selected to form, when in a dissolved state in the carrier liquid, another solution which precipitates to form said developer particles, said substances being selected in quantity such that by reaction therebetween there is no surplus of the conductive substance after reaction in the carrier liquid whereby the resistivity of the carrier liquid in its final state is not lowered in insulating value, and whereby the developer particles are themselves formed in the liquid to be shielded against oxidation and are held in such liquid until used as a developer, said carrier liquid being a hydrocarbon liquid, and said insulating substances being selected from the group consisting of: Quinalizarin, anthranilic acid, Alizarin, Hydroquinone, Chloranil, sym-diphenylcarbazide, diphenylthiocarbazide, 2-Furoic Acid, Tetrachlorophthalic anhydride, fumaric acid, Naphthalene-2-Sulphonic Acid, Citral, Cinnomoldehyde and Diphenyliamine, said conductive substance being selected from the group consisting of: cobalt octoate, the octoates and naphthenates of zinc, lead, manganese, copper, zirconium, iron and chromium, copper nonyl phthalate and ferric chloride.