PURPOSE: To obtain a leuco dye color developer realizing a recording superior in color forming properties, resistance to fading, and light fastness by using a mixture of boron nitride and oxides of IVb group of the periodic table or a mixture of boron nitride, oxides of IVb group of the periodic table, and SiO2.
CONSTITUTION: The use of boron nitride and at least one of oxides of IVb group of the periodic table, such as TiO2 and ZrO2 or the use of a mixture of boron nitride, at least one of oxides of IVb group of the periodic table, e.g. TiO2 and ZrO2, and SiO2 as a leuco dye developer enhances color forming properties, resistance to fading, and light fastness. Furthermore, the high whiteness of boron nitride, oxides of IVb group in the periodic table, e.g. TiO2 and ZrO2, and SiO2 enables a favorable image to be obtained.
IWASAKI FUMIHARU
SAKOJIRI HIROMICHI
