| 摘要 |
PURPOSE:To enhance absorbability in a near infrared region and storage stability by utilizing color forming reaction of a leuco dye represented by a predetermined general formula and a developer forming a color upon the contact with the leuco dye. CONSTITUTION:A leuco dye composed of a compound represented by the formula I or II and a developer forming a color upon the contact with the leuco dye, for example, an electron acceptive compound such as an inorg. acid, an org. acid or a phenolic substance are used and the color forming reaction between both of them is utilized. In the formulae I, II, R1 and R2 are lower alkyl groups, R3 is a hydrogen atom, a lower alkyl group or a lower alkyoxy group, X<1> is a dialkylaminophenyl group, X<2> is a phenyl group which may be substituted with a lower alkoxy group, Y<1> is a hydrogen atom or a lower alkyl group, Y<2> is a lower alkyl group or X and A is a benzene ring or a naphthalene ring. Further, a fluorane type leuco dye is together used in the correction of a hue and the correction of absorbing characteristics. |
