Thermosensitive transfer ink sheet, and image forming method

Provided are a thermosensitive transfer ink sheet making it possible to overcome blocking and sticking and further giving a print having a high Dmax and a high image quality; and an image forming process using the same. The sheet is a thermosensitive transfer ink sheet including a base film which has, over one surface thereof, at least a thermal transfer layer containing a thermally transferable dye and a binder resin, and has, over the other surface thereof, a heat-resistant lubricant layer, wherein the thermal transfer layer comprises a polycondensed aromatic compound having 4 or more rings; and the above-mentioned process is an image forming process using the sheet.