Electrographic liquid developer and method of making same
AssigneeEastman Kodak Company
InventorsDomenic Santilli, John W. May
Life of this patent
Estimating the term…
Abstract
An electrographic liquid developer includes a fluorescent toner diluted in a liquid developer vehicle which has a high flash point and a low vapor pressure. The liquid developer vehicle preferably is a mixed liquid alkane which has a flash point over 140.degree. F. and a vapor pressure less than 5.2 mm of mercury at 38.degree. C. The fluorescent toner is preferably made as follows: a solution is prepared which comprises an organic solvent, a fluorescent dye, and an organic polymer. A pigment is precipitated by mixing the solution with a non-solvent for the polymer in the presence of a dispersant. The pigment is melt-compounded with a polymeric organic binder and the melt-compounded mixture is comminuted.
Claims4
A method of making an electrographic liquid developer having a fluorescent toner for use in electrostatography comprising:
- making a fluorescent toner by preparing a solution which comprises:
- organic solvent;
- a fluorescent dye soluble in said solvent;
- and
- an organic polymer soluble in said solvent;
- mixing said solution with a sufficient amount of a liquid which is a non-solvent for said polymer to precipitate particles of a pigment which comprises said dye in solid solution with said polymer, said mixing being in the presence of a dispersant soluble in said non-solvent in an amount sufficient to prevent said precipitating pigment particles from agglomerating to a particle size greater than 1 .mu.m;
- melt-compounding a mixture which comprises polymeric organic binder and said pigment;
- comminuting said melt-compounded mixture;
- and
- diluting an aliquot of said fluorescent toner in a liquid developer vehicle having a high flash point and a low vapor pressure.
Dependencies are inferred from the claim text.