The co presence of a phenol derivative represented by chemical formula 1 and a diphenyl sulfone derivative represented by chemical formula 2 in the thermosensitive color developing layer is presumed to support the well balanced performance by increasing the stability of the electron transfer complex that is {HEAD ~ the reaction product} of a color developing agent and {TAIL ~ a basic dye} 
The co presence of a phenol derivative represented by chemical formula 1 and a diphenyl sulfone derivative represented by chemical formula 2 in the thermosensitive color developing layer is presumed to support the well balanced performance by increasing the stability of the electron transfer complex that is { HEAD ~ the reaction product } of a color developing agent and { TAIL ~ a basic dye }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL