Process for preparing positive electrostatic liquid developers with acidified charge directors
US5066821A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 11, 1990 |
| Grant date | Nov 19, 1991 |
| Priority date | — |
| Expiry date | May 11, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G9/1355
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process for preparing an improved positive-working electrostatic liquid developer comprising PA0 (A) dispersing at an elevated temperature in a vessel a thermoplastic resin and a nonpolar liquid having a Kauri-butanol value of less than 30, while maintaining the temperature in the vessel at a temperature sufficient to plasticize and liquify the resin and below that at which the nonpolar liquid degrades and the resin decomposes, PA0 (B) cooling the dispersion, either PA1 (1) without stirring to form a gel or solid mass, followed by shredding the gel or solid mass and grinding by means of particulate media; PA1 (2) with stirring to form a viscous mixture and grinding by means of particulate media; or PA1 (3) while grinding by means of particulate media to prevent the formation of a gel or solid mass; PA0 (C) separating the dispersion of toner particles having an average particle size of less than 30 .mu.m from the particulate media, and PA0 (D) adding to the dispersion subsequent to Step (A) a nonpolar liquid soluble ionic or zwitterionic charge director compound mixed with an acid having a pKa of <4.2 and a solubility of at least 0.5% based on the weight of charge director compoun…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.