| 摘要 |
PURPOSE:To prevent background fog, in the material of a printer, by adding a nonionic surfactant represented by a specific formula and having a predetermined HLB value to a thermal color forming layer. CONSTITUTION:At least one kind of a compd. being a nonionic surfactant with an BLB value of 10-14 represented by formula (wherein m and n are numerical values setting m+n to 5-12) is added to the thermal color forming layer containing a colorless or light-colored leuco dye and a coupler forming a color upon the reaction with the leuco dye at the time of heating formed on a support. The surfactant is pref. added to the thermal color forming layer in an amt. of 0.01-10% by wt. of the leuco dye. When the nonionic surfactant is added at the time of the dispersion of the leuco dye, the grinding time finely grinding the leuco dye so as to have a specific particle size can be shortened. |
