PRODUCTION OF LIQUID DEVELOPER FOR ELECTROPHOTOGRAPHY

摘要

PURPOSE:To obtain a liquid developer for electrophotography which provides excellent image reproducibility without image flow and double images by subjecting a liquid developer for electrophotography contg. a coloring agent coated with a high-polymer resin dispersed in an electrically insulating carrier liquid and dispersant to a heating treatment. CONSTITUTION:The coloring agent and the resin which is a coating agent are mixed. The mixture is melted and kneaded by a kneading machine at the softening temp. of the coating agent or above to obtain the intimate mixture. The resulted intimate mixture is subjected to dry pulverization then to wet dispersion by a dispersing machine together with the dispersant, by which the thickened toner liquid is obtd. The thickened toner liquid is added to a carrier liquid contg. an electric charge controlling agent by which the liquid developer for electrophotography is obtd. The thickened toner liquid or the liquid for use diluted by the carrier liquid are subjected to the heating treatment at the temp. in a softening range from the temp. lower by 20 deg.C than the softening initiation temp. of the coating agent resin constituting the toner particles. An important point is to execute the heating treatment after the end of dispersion.