| 摘要 |
PURPOSE:To obtain an ink sheet free of bleeding due to a binder, printing of broken images or generation of voids in printed images and capable of being satisfactorily used with a high-density thermal head, by incorporating a coloring material comprising specified carbon black and a specified glycerol derivative into an ink layer. CONSTITUTION:A coloring material comprising thermal black and/or furnace black and a glycerol derivative of formula (I) are incorporated in an ink layer. In formula (I), each of R1-R5 is OH or COOR or COONHR, wherein R is a 15-30 long chain alkyl, each of at least three of R1-R5 being COOR or COONHR. The amount of carbon black is 5-30wt% based on the glycerol derivative. If the amount of carbon black is less than 5wt%, printed density is low, and printing quality is poor. If the amount of carbon black is more than 30wt%, the concentration of the coloring material in the ink is excessively high, so that the flexibility of an ink film provided on an ink sheet is impaired, and the ink tends to spontaneously exfoliate from a base of the ink sheet. |
