Patent ID: 7144672

Claim:
An image forming method of a thermal transfer recording material comprising an ink sheet comprising, on a substrate sheet, an ink layer containing a thermally diffusible dye capable of forming a chelate with a metal, and an image receiving sheet comprising, on a substrate, a dye receiving layer containing a metal ion containing compound capable of forming a metal chelate compound upon reaction with the thermally diffusible dye, the method comprising the steps of: (a) superimposing the ink layer onto the dye receiving layer, and (b) imagewise heating the ink sheet based on a recording signal to transfer the thermally diffusible dye from the ink sheet to the image receiving sheet, wherein the imagewise heating is performed at a print rate of not more than 1.5 msec/line, and the dye receiving layer further contains a metal ion species different from the metal ion containing compound or at least one compound selected from the group of a sorbitan fatty acid ester, a sorbitan fatty acid ester having a polyoxyethylene group, a phosphoric acid ester, a compound represented by the following formula (1) and a compound represented by the following formula (2): HO—[CH 2 CH 2 O] n —[CH 2 CH(CH 3 )O] m —H formula (1) wherein n is an integer of 100 to 200; m is an integer of 10 to 50; HO—(W—O) p —H formula (2) wherein W is —CH 2 CH 2 —, —CH 2 CH 2 CH 2 —, —CH 2 CH(CH 3 )— or —CH 2 CH 2 CH 2 CH 2 —; and p is an integer of 5 to 50.