by nihon denshoku co ltd and the following value was determined equ1 1 hour after passing the sheets through the calender ii sunlight resistance of colored characters the color developer sheet colored by passing it through the aforesaid calender was exposed to the sun for 2 hours and the reflectance was measured by means of a colorimetric color difference meter manufactured by nihon denshoku co ltd and the following value was determined equ2 iii surface strength the measurement was carried out by means of an igt tester manufactured by kumai riki co ltd by using ipi no 4 ink and a b spring the strength is expressed by or u03b4 the test was carried out by means of a miyaster 17 type printer manufactured by miyakoshi machine factory by using commercially available offset ink blue the degree of stains on blanket in this case is expressed by u03b4 or x a commercially available top sheet 34 mitsubishi ncr paper joh 40 34 for no carbon copying paper and each of under sheets the color developer sheets obtained in examples 1 and 2 and comparatives examples 1 2 and 3 were put together to make a set of no carbon copying.