申请人:Ricoh Company, Ltd.
公开号:US05057154A1
公开(公告)日:1991-10-15
A leuco dye of the formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 each represent a lower alkyl group; A represents ##STR2## in which R.sup.9 and R.sup.10 each represent hydrogen, provided that both R.sup.9 and R.sup.10 may not be hydrogen, --CN or --COR.sup.14 in which R.sup.14 represents a phenyl group which is unsubstituted or is substituted by an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, or a halogen, a naphthyl group which is unsubstituted or is substituted by an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms or a halogen, or a lower alkoxyl group, ##STR3## in which ##STR4## represents a phenyl group or a naphthyl group, R.sup.11 represents hydrogen, a lower alkyl group, a halogen, an amino group, which is unsubstituted or is substituted by an alkyl group having 1 to 4 carbon atoms, or a nitro group, or ##STR5## in which R.sup.12 represents a lower alkyl group, or ##STR6## in which R.sup.13 represents hydrogen, a lower alkyl group, a halogen, a hydroxyl group, a trifluoromethyl group, a nitro group, an amino group which is unsubstituted or is substituted by an alkyl group having 1 to 4 carbon atoms, or amide group. These dyes absorb in the near-infrared region and yields colored images with a color developer therefor with excellent preservability.
化学式(I)的白色染料:其中R.sup.1,R.sup.2,R.sup.3,R.sup.4,R.sup.5,R.sup.6,R.sup.7和R.sup.8各代表较低的烷基基团; A代表##STR2##其中R.sup.9和R.sup.10各代表氢原子,但前提是R.sup.9和R.sup.10不能同时为氢原子,-CN或-COR.sup.14,其中R.sup.14代表未取代或由具有1至4个碳原子的烷基基团,1至4个碳原子的烷氧基团或卤素,未取代或由具有1至4个碳原子的烷基基团,1至4个碳原子的烷氧基团或卤素,或较低的烷氧基团,##STR3##其中##STR4##表示苯基或萘基,R.sup.11表示氢原子,较低的烷基基团,卤素,未取代或由具有1至4个碳原子的烷基基团取代的氨基基团,或硝基基团,或##STR5##其中R.sup.12表示较低的烷基基团,或##STR6##其中R.sup.13表示氢原子,较低的烷基基团,卤素,羟基,三氟甲基基团,硝基,未取代或由具有1至4个碳原子的烷基基团取代的氨基基团,或酰胺基团。这些染料在近红外区域吸收,并与其颜色显影剂产生优异的保存性的有色图像。