Am International Incorporated

Ray H Luebbe, Jr

George A Gibson

Joseph S Chow

A liquid toner for developing electrostatic latent images, at speeds in excess of 100 ft./min., by electrophoretic movement of pre-charged particles of a thermoplastic polymer in a nonpolar carrier liquid, which reduces drag is disclosed wherein the particles are present in about 10% by weight of the weight of the carrier liquid, and no more than 10% by volume of such toner particles having a size less than 1.0 micron as measured by an Horiba Capa-700. The nonpolar liquid has, typically, a volume resistivity in excess of 10.sup.9 ohm centimeters, a dielectric constant no greater than 3.5, and a vapor pressure of less than 10 millimeters of Mercury at 25 degrees C. The toner composition also includes a quantity of charge director for imparting an electrostatic charge of predetermined polarity to said particles. The toner particles may have a plurality of fibers integrally extending therefrom. Also disclosed is a method of electrostatic printing, at speeds of at least 100 feet-minute, using such liquid developers.

Method of electrostatic printing and toner used in such method

Improved charge control agent for electrophotographic liquid toners comprising a mixture of lecithin and an alkylated poly-N-vinyl pyrrolidone polymer is disclosed. Methods include applying liquid toners comprising such charge control agent mixture to an electroconductive substrate that has been electrostatically charged in the image areas thereof.

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Centerville, OH, United States of America

Ray H Luebbe, Jr