Process for preparing electrophotographic liquid developing compositions

Claim 2

The process according to claim 1 wherein the same liquid is employed as the liquid precipitation medium and the binder solvent and wherein only a portion of this liquid is removed during removal of said binder solvent.

Claim 3

The process according to claim 1 wherein admixture of the dye and mordant is accomplished by forming a solution of a dye-mordant salt in an organic solvent for said dye-mordant salt and mixing said dye-mordant salt solution with a mixture of the polymeric binder, the solvent therefor and the liquid precipitation medium.

Claim 4

The process according to claim 4 wherein said mixture of polymeric binder, solvent therefor and liquid precipitation medium also contains a surfactant which is soluble in the liquid carrier.

Claim 5

The process according to claim 1 wherein admixture of the dye and mordant is accomplished by dissolving the dye in a first mixture of polymeric binder and solvent therefor, dissolving the mordant for the dye in a second mixture of polymeric binder and a solvent therefor, and mixing said first mixture with said second mixture in the presence of the liquid precipitation medium.

Claim 6

The process according to claim 6 wherein the mixture of said first mixture and said second mixture occurs in the presence of the liquid precipitation medium and also in the presence of a surfactant which is soluble in the liquid carrier.

Claim 7

The process according to claim 6 wherein said second mixture of polymeric binder and liquid solvent therefor also contains a surfactant which is soluble in the liquid carrier.

Claim 8

A process for making electrophotographic developers having toner particles dispersed in an organic liquid carrier having a dielectric constant less than about 3.0 and a resistivity greater than about 1010 ohm-cm. which comprises admixing an acid dye and a basic mordant for said dye in the presence of (1) a polymeric binder, (2) an organic solvent for said binder and (3) an alkylated aromatic hydrocarbon; removing the solvent for said binder; and admixing the resultant dope with the liquid carrier to form a substantially stable dispersion of finely divided toner particles in the liquid carrier, said toner particles having a substantially uniform size within the range of from about 0.1 microns to about 2.0 microns and comprising a particulate dye-mordant salt precipitate dispersed in the polymeric binder; said acid dye being selected from the group consisting of Brilliant Alizarine Light Red B. C.I. acid Red 58; copper phthalocyanine tetrasodium sulfonate, C.I. 74220; 4,8-disulfonaphthyl-2-azo-4-(3-methyl-1-p-sulfophenyl-5-pyrazolone); anthraquinone Blue B, C.I. 63010; and Solantine Pink 4 BL, C.I. 25380; said basic mordant being selected from the group consisting of triphenylguanidine, di-o-tolylquinidine, Alpha -naphthylamine, dioctylamine and N,N-dimethyldodecylamine.

Claim 9

The process according to clAim 9 wherein admixture of the acidic dye and basic mordant occurs in the presence of a surfactant selected from the group consisting of a polyphosphoric co-ester of an alkylphenol and a polyoxyethylene sorbitan fatty ester, polyoxyethylene sorbitan trioleate, polyoxyethylene tridecylphenol, polyoxyethylene dodecylphenol and a fatty alkanolamide.

Claim 10

A process for making electrophotographic developers having toner particles dispersed in an organic liquid carrier having a dielectric constant less than about 3.0 and a resistivity greater than about 1010 ohm-cm. which comprises admixing a basic dye and an acidic mordant for said dye in the presence of (1) a polymeric binder, (2) an organic solvent for said binder and (3) an alkylated aromatic hydrocarbon; removing the solvent for said binder; and admixing the resultant dope with the liquid carrier to form a substantially stable dispersion of finely divided toner particles in the liquid carrier, said toner particles having a substantially uniform size within the range of from about 0.1 microns to about 2.0 microns and comprising a particulate dye-mordant salt precipitate dispersed in the polymeric binder; said basic dye being selected from the group consisting of Astraphloxine FF, C.I. 48070; Rhodamine B, C.I. 45170; Rhodamine 6G, C.I. 45160; methylene Blue, C.I. 52015; Toluidine Blue, C.I. 52040; and Auramine G, C.I. 41005; said acidic mordant being selected from the group consisting of phosphotungstic acid, phosphomolybdic acid, tannic acid, tungstosilicic acid and molybdosilicic acid.

Claim 11

The process according to claim 11 wherein admixture of the basic dye and the acidic mordant occurs in the presence of a surfactant selected from the group consisting of a polyphosphoric co-ester of an alkylphenol and a polyoxyethylene sorbitan fatty ester, polyoxyethylene sorbitan trioleate, polyoxyethylene tridecylphenol, polyoxyethylene dodecylphenol and a fatty alkanolamide.

Claim 12

A process for making electrophotographic developers having toner particles dispersed in an organic liquid carrier having a dielectric constant less than about 3.0 and a resistivity greater than about 1010 ohm-cm. which comprises admixing a dye and a mordant for said dye in the presence of (1) a polymeric binder comprising a material separate and distinct from sad mordant, (2) an organic solvent for said binder, and (3) a first amount of an organic liquid precipitation medium which is capable of dissolving or forming a colloidal suspension of the polymeric binder and which is miscible with the liquid carrier; removing the solvent for said binder and the liquid precipitation medium to form a dry powder admixture of said binder, dye, and mordant for said dye; admixing said dry powder in a second amount of said organic liquid precipitation medium sufficient to form a dope thereof; and admixing the resultant dope with the liquid carrier to form a substantially stable dispersion of finely-divided toner particles in the liquid carrier, said toner particles having a substantially uniform size within the range of from about 0.05 microns to about 20 microns and comprising a particulate dye-mordant salt precipitate dispersed in the polymeric binder.

Claim 13

The process according to claim 13 wherein admixture of a dye and mordant for the dye occurs in the presence of a surfactant which is soluble in the liquid carrier.

Claim 14

A process for making electrophotographic developers having toner particles dispersed in an organic liquid carrier having a dielectric constant less than about 3.0 and a resistivity greater than about 1010 ohm-cm. which comprises admixing a dye and a mordant for said dye in the presence of (1) a polymeric binder comprising a material separate and distinct from said mordant, (2) an organic solvent for said binder, and (3) a first amount of an alkylated aromatic hyDrocarbon; removing the solvent for said binder and the alkylated aromatic hydrocarbon to form a dry powder admixture of said binder, dye, and mordant for said dye; admixing said dry powder in a second amount of said alkylated aromatic hydrocarbon sufficient to form a dope thereof; and admixing the resultant dope with the liquid carrier to form a substantially stable dispersion of finely-divided toner particles in the liquid carrier, said toner particles having a substantially uniform size within the range of from about 0.05 microns to about 20 microns and comprising a particulate dye-mordant salt precipitate dispersed in the polymeric binder.

Claim 15

The process according to claim 15 wherein admixture of the dye and mordant for the dye occurs in the presence of a surfactant which is soluble in the liquid carrier.