Heat sensitive recording sheet

摘要

A heat sensitive recording sheet having a heat sensitive color forming layer wherein a mixture of fluoran compounds of the following formulas I and II is used as a color former; (I) wherein R1 is a hydrogen atom, an alkyl group having from 1 to 8 carbon atoms, a tetrahydrofurfuryl group, a substituted or unsubstituted phenyl group or a cycloalkyl group, R2 is a hydrogen atom, a chlorine atom, a fluorine atom, a lower alkyl group, a lower alkoxy group, a lower alkoxyalkyl group, a phenyl group or a benzyl group, and R3 is a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, a lower alkyl group or an acyl group; and (II) wherein each of R4 and R5 is a hydrogen atom, an alkyl group having from 1 to 8 carbon atoms, a substituted or unsubstituted phenyl group or a cycloalkyl group, or R4 and R5 may, together with the adjacent nitrogen atom, form a ring of the formula each of R6 and R7 is a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, a lower alkyl group, a lower alkoxy group, a lower alkoxyalkyl group, a phenyl group or a benzyl group, and R8 is a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, a lower alkyl group or an acyl group.