JAMES DAVID LARSON
Medical Practice in Wilmington, DE

4681831, Jul 21, 1987

Jun 30, 1986

6/880155

James R. Larson - Wilmington DE
Torence J. Trout - Wilmington DE

E. I. Du Pont de Nemours and Company - Wilmington DE

G03G 912

430114

A liquid electrostatic developer containing negatively chargeable resin particles with improved charging characteristics, said developer consisting essentially of (A) nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount, (B) nonpolar liquid soluble ionic or zwitterionic charge director compound, and (C) resin particles of a polymer containing at least one acidic constituent having a pKa less than 4. 5, preferably 3. 0, at 25. degree. C. in water and an acid number due to said acidic constituent of at least one. The average resin particle size by area is less than 10. mu. m. Optionally a colorant and other additives or adjuvants are present. The liquid electrostatic developer is useful in copying making proofs including digital color proofs, lithographic printing plates, and resists.

4760009, Jul 26, 1988

Dec 4, 1985

6/804385

James R. Larson - Greenville DE

E. I. Du Pont de Nemours and Company - Wilmington DE

G03G 912

430137

Process for preparation of toner particles for electrostatic imaging comprising (A) dispersing in a vessel at elevated temperature thermoplastic resin, nonpolar liquid and optionally a colorant, e. g. , pigment, using moving particulate media, the temperature being sufficient to plasticize and liquify the resin and below the decomposition temperature of resin and/or colorant and below nonpolar liquid boiling point; (B) cooling the dispersion while maintaining continuous movement of the particulate media during and subsequent to cooling whereby toner particles are formed having an average by area particle size of less than 10. mu. m and a plurality of fibers; and (C) separating the dispersion having a concentration of toner particles from the particulate media. After step (C) the dispersion can be diluted with additional nonpolar solvent and/or a charge director can be added. The dispersion having a concentration of toner particles is useful for the preparation of copies and proofs of various colors.

4772528, Sep 20, 1988

May 6, 1987

7/046539

James R. Larson - Wilmington DE
Torence J. Trout - Wilmington DE

E. I. Du Pont de Nemours and Company - Wilmington DE

G03G 912

430115

A liquid electrostatic developer containing negatively chargeable resin particles with improved charging characteristics, said developer consisting essentially of (A) nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount; (B) resin particles of a blend of at least two polymers, at least one polymer containing at least one acidic constituent having a pKa of less than 4. 5 measured at 25. degree. C. in water, and the blend having an acid number of at least one due to said acidic constitutent; the resin particles having an average by area particle size of less than 10. mu. m, and (C) nonpolar liquid soluble ionic or zwitterionic charge director compound. A preferred polymer blend is composed of polystyrene and a sulfonated polymer, e. g. , poly(2-acrylamido-2-methyl-1-propanesulfonic acid).

4783388, Nov 8, 1988

Jun 17, 1987

7/063219

Lyla M. El-Sayed - West Chester PA
James R. Larson - Greenville DE

E. I. Du Pont de Nemours and Company - Wilmington DE

G03G 912

430115

Negative-working electrostatic liquid developer having improved charging characteristics consisting essentially of (A) nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount, (B) thermoplastic resin particles having an average by area particle size of less than 10. mu. m, (C) nonpolar liquid soluble ionic or zwitterionic compound, and (D) a quaternaryammonium hydroxide compound as defined, e. g. , tetraethylammonium hydroxide, tetrabutylammonium hydroxide, etc. , soluble in an amount of at least 0. 5 part per million by weight in the nonpolar liquid. The electrostatic liquid developer is useful in copying, making proofs including digital color proofs, lithographic printing plates, and resists.

4780388, Oct 25, 1988

May 26, 1987

7/053864

James R. Larson - Wilmington DE

E. I. Du Pont de Nemours and Company - Wilmington DE

G03G 912

430115

Electrostatic liquid developer having improved charging characteristics consisting essentially of (A) nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount, (B) thermoplastic resin particles having an average by area particle size of less than 10. mu. m, (C) nonpolar liquid soluble ionic compound, and (D) at least one organic polyamine compound having at least 2 amino groups present on adjacent carbon atoms. Optionally, a colorant, e. g. , a pigment; metallic soap can be present. The electrostatic liquid developer is useful in copying, making proofs including digital color proofs, lithographic printing plates, and resists.

4783389, Nov 8, 1988

Mar 27, 1987

7/030993

Torence J. Trout - Wilmington DE
James R. Larson - Wilmington DE

E. I. Du Pont de Nemours and Company - Wilmington DE

G03G 912

430137

Process for the preparation of toner particles for liquid electrostatic imaging comprising (A) mixing a thermoplastic resin and a nonpolar liquid at a temperature sufficient to plasticize and liquify the resin and below that at which the nonpolar liquid boils and the resin decomposes, (B) cooling the mixture to form resin particles in the nonpolar liquid, (C) reducing the size of the resin particles to below about 30. mu. m by passing the product of step (B) through at least one liquid jet interaction chamber at a liquid pressure of at least 1000 p. s. i. , e. g. , a Microfluidizer. RTM. The process produces liquid electrostatic developer quicker than other known processes, the developer being useful in copying, making proofs, including digital proofs, etc.

4702985, Oct 27, 1987

Apr 28, 1986

6/856392

James R. Larson - Greenville DE

E. I. Du Pont de Nemours and Company - Wilmington DE

G03G 912

430115

Electrostatic liquid developer having improved charging characteristics comprising (A) nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount, (B) thermoplastic resin particles having an average by area particle size of less than 10. mu. m, (C) nonpolar liquid soluble ionic or zwitterionic compound, and (D) at least one aminoalcohol compound. The electrostatic liquid developer is useful in copying, making proofs including digital color proofs, lithographic printing plates, and resists.