Patent ID: 7312176

Claim:
A thermally sensitive recording medium comprising a thermally sensitive recording layer containing a colorless or pale colored basic colorless dye and an organic color developing agent as main components on a support, wherein the thermally sensitive recording medium contains; a compound represented by the following general formula (1) as the organic color developing agent, wherein, R a and R b each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, A represents an integer of 1 to 6; B represents 0, 1, or 2, m 1 and m 2 each independently represent 0 or an integer of 1 to 3, but m 1 and m 2 are not both 0, R c and R d each independently represent a nitro group, a carboxyl group, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, m 3 and m 4 each independently represent 0 or an integer of 1 or 2, when m 3 and m 4 are both 2, R c and R d may be different from each other; M represents CO or NR e CO, wherein, R e represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, when M is CO, m 1 is 1, and when m 1 is 0 and M is NR e CO, B is not 0, and an oxalate compound represented by the following the general formula (2) as a sensitizer, wherein, R 1 represents a halogen atom.