Claims
- 1. An electrographic liquid developer comprising an aliquot of fluorescent toner diluted in a liquid developer vehicle having a high flash point and a low vapor pressure.
- 2. An electrographic liquid developer of claim 1 wherein said liquid developer vehicle has a flash point greater than 140.degree. F.
- 3. An electrographic liquid developer of claim 1 wherein said liquid developer vehicle is a mixed liquid alkane which has a flash point greater than 140.degree. F. and has evaporation rate less than 0.1 of that of n-butyl acetate.
- 4. An electrographic liquid developer of claim 3 wherein said liquid developer vehicle has vapor pressure at 38.degree. C. of less than 5.2 millimeters of mercury.
- 5. An electrographic liquid developer having a fluorescent toner for use in electrostatography made according to the method:
- 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.
- 6. In an electrographic imaging system in which a latent electrographic image is formed on a photoconductive or dielectric surface, is developed into a toner image by means of a liquid fluorescent toner, the toned image is raster scanned by a beam of light to produce an image wise optical emission, and the image wise optical emission is detected photoelectrically to produce an electrical image signal, the improvement comprising:
- the use of an electrographic liquid developer comprising an aliquot of fluorescent toner diluted in a liquid developer vehicle having a high flash point and a low vapor pressure.
- 7. The improvement of claim 6 wherein said electrographic liquid developer has a liquid developer vehicle with a flash point greater than 140.degree. F.
- 8. The improvement of claim 6 wherein said liquid developer vehicle is a mixed liquid alkaline which has a flash point greater than 140.degree. F. and has an evaporation rate less than 0.1 of that of small n-butyl acetate.
- 9. The improvement of claim 6 wherein said liquid developer vehicle of said electrographic liquid developer has vapor pressure at 38.degree. C. of less than 5.2 mm of mercury.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a divisional application of U.S. Pat. application Ser. No. 742,139, filed Aug. 8, 1991 U.S. Pat. No. 5,176,980 entitled "An Electrographic Liquid Developer and Method of Making Same", inventors Domenic Santilli and John W. May.
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Divisions (1)
|
Number |
Date |
Country |
Parent |
742139 |
Aug 1991 |
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