E.i. Dupont De Nemours and Company

Dximaging

David E Blair

James R Larson

Gregg A Lane

Kathryn A Pearlstine

William A Houle

Bradley J Gollhardt

System for replenishing liquid developer in equipment, such as a printer, whereby the percent of toner solids is maintained at about 0.5 to 4% by weight based on the total weight of liquid developer, the system comprising at least one liquid toner concentrate vessel containing aggregates of thermoplastic resin particles, median particle size (volume weighted) greater than 15 .mu.m, and with 90% of the particles (volume weighted) not less than 30 .mu.m, composed of 50 to 100% by weight of particles and 0 to 50% by weight carrier liquid; a liquid vessel containing carrier liquid, means communicating each of said vessels with a dispersing vessel containing high shearing or high impact means wherein contents of the liquid toner concentrate vessel and the liquid vessel are supplied thereto and the resin particles are dispersed in the carrier liquid to form particles having a median particle size (volume weighted) of less than 15 .mu.m, and with 90% of the particles (volume weighted) less than 30 .mu.m in an amount of about 0.5 to 20% by weight of resin particles and about 99.5 to 80% by weight carrier liquid said dispersion being supplied and metered into the supply vessel containing original liquid developer to maintain the desired weight of solids. The system is useful in copying, proofing, etc., equipment, and the liquid developer is useful for making copies, proofs, lithographic printing plates and resists.

System for replenishing liquid electrostatic developer

Process for preparation of toner particles for electrostatic liquid developers utilizing a single vessel wherein (A) a thermoplastic resin and hydrocarbon liquid having a Kauri-butanol value of less than 120 at a total of solids of at least 22% by weight are dispersed in the vessel by moving particulate media (crating shear) at elevated temperature to plasticize and liquify the resin, (B) while the particulate media are maintained in continuous motion the dispersion is cooled whereby the resin precipitates in the form of toner particle having an average by area particle size of 10 .mu.m or less, and (C) the particulate media are removed. Liquid electrostatic developers are prepared by the addition of a charge director compound. The liquid developers are prepared in a shorter time that previously known processes. The liquid developers are useful for preparation of copies and proofs of various colors.

Use of high percent solids for improved liquid toner preparation

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Chester Springs, PA, United States of America

David E Blair