Imaging apparatus and improved toner therefor
The invention relates to a liquid toner and imaging apparatus provided with an imaging surface having a liquid toner image formed thereon on fibrous toner particles and carrier liquid. The fibrous toner particles can be composed of a polymer portion and pigment dispersed therein, where the polymer portion comprises a surface of the fibrous toner particles and is insoluble in the carrier liquid at temperatures below 40° C., so that the polymer portion will not dissolve or solvate in storage. The polymer portion also is solvatable by the carrier liquid only at temperatures above 50° C. The carrier liquid has, as a major component, first liquid hydrocarbon having a first rate of evaporation, and, as a minor component, second liquid hydrocarbon having a second rate of evaporation which, at room temperature, is at least an order of magnitude less than the first rate of evaporation.
1. A multicolor electrostatic imaging system comprising:
an imaging apparatus to produce one or more images on a substrate; and
a toner reservoir having a liquid toner to form the one or more images,
wherein the liquid toner comprises fibrous toner particles and carrier liquid;
said carrier liquid comprising, as a major or component, first liquid hydrocarbon having a first rate of evaporation, and, as a minor component, second liquid hydrocarbon having a second rate of evaporation which, at room temperature, is at least an order of magnitude less than the first rate of evaporation; and
said fibrous toner particles comprising a polymer portion and pigment dispersed in said polymer portion, said polymer portion comprising a surface of said fibrous toner particles and being insoluble in said carrier liquid at temperatures below 40 degrees Celsius so that the polymer portion will not dissolve or solvate in storage, and solvatable by said carrier liquid only at temperatures above 50 degrees Celsius.
2. The multicolor electrostatic imaging system as recited in claim 1 , wherein the major component has a vapor pressure at 100 degrees Fahrenheit greater than 0.05 psia when measured according to ASTM standard D 2879.
3. The multicolor electrostatic imaging system as recited in claim 2 , wherein said major component is liquid hydrocarbon having a 95% evaporation time at room temperature of less than 10 hours.
4. The multicolor electrostatic imaging system as recited in claim 2 , wherein said major component has a 95% evaporation time at room temperature of less than 6 hours.
5. The multicolor electrostatic imaging system as recited in claim 1 , wherein said first liquid hydrocarbon and said second liquid hydrocarbon are substantially non-conducting having an electrical volume resistivity in excess of 10 9 ohm-cm and a dielectric constant below 3.0.
6. The multicolor electrostatic imaging system as recited in claim 1 , wherein the fibrous toner particles comprise approximately 1 to 2% of the liquid toner in the toner reservoir by weight.
7. The multicolor electrostatic imaging system as recited in claim 1 , wherein the imaging apparatus comprises an intermediate transfer member having a release outer layer to receive toner from the imaging surface and to solvate carrier liquid the received toner.