| 摘要 |
PURPOSE:To enhance the storage stability and high speed recording properties of a recording image by using a compd. represented by a predetermined formula as a developer forming a thermal color forming layer along with a leuco dye. CONSTITUTION:As a developer forming a thermal color forming layer and allowing a leuco dye to develop a color by heating, a compd. represented by formula (wherein X is a lower alkyl group or a halogen atom and n is an integer of 0-3. When n is 2-3, X may be same or different), for example, hydroxyphthalic acid or a derivative thereof is used. Further, by providing an intermediate layer based on spherical fine hollow particles with a mean particle size of about 2-10mum and a percentage of hollowness of about 90% or more composed of a thermoplastic resin between a support and the thermal color forming layer, the enhancement of sensitivity due to the efficient practical use of heat energy can be also enhanced. |
