| 摘要 |
PURPOSE:To obtain a heat sensitive, color developing and negatively chargeable powdered coloring agent giving a favorable record by electrostatic charging without causing defects such as stain by adding a specified color developing dye precursor, an acidic developer, and a compound which is solid at ordinary temp. and is melted by heating. CONSTITUTION:This negatively chargeable powdered coloring agent contains >=1 kind of color developing dye precursor (a) selected from fluorane, triphenylmethanephthalide, phenothiazine and spiropyrane compounds, an acidic developer (b), and a compound (c) which is solid at ordinary temp. and is melted by heating. The dye precursor (a) is a leuco dye or a lactone compound which is generally used as a heat sensitive dye, and a fluorane dye, a triphenylmethanephthalide compound or the like is used as the precursor (a). The preferred compound (c) has 40-150 deg.C melting temp., and the ester of fatty acid with higher alcohol, e.g., vegetable wax, animal wax or paraffin wax is used as the compound (c). |
