| 摘要 |
PROBLEM TO BE SOLVED: To make color forming properties excellent and improve heat-resistant texture color stability at a white paper portion in a recording medium by employing a sulfonyl guanidine compound represented by a specific formula as a developer. SOLUTION: A sulfonyl guanidine compound represented by the formula is used as a developer (wherein, R<1> and R<2> each independently represents a hydrogen atom, an alkyl group, an alkoxyl group. a halogen atom, a nitro group, and a substituted or an unsubstituted aryl group. Further, m and n each represents integers of 1-5). Furthermore, and a substituent group in the case where R<1> and R<2> each represents the aryl group, such a group may be the one that does not inhibit color forming power, and includes the alkyl group, the alkoxy group, a halogen atom, etc., The guanidine compound is used as the developer for a leuco dye and, further, by introducing a sulfonyl group into the guanidine compound, heat-resistance texture color stability at a white paper portion in a heat-sensitive recording medium is greatly improved, and high color forming properties can be obtained. |
