Patent ID: 6902876

Claim:
A concentrated color developer composition comprising: a color developing agent, a sulfite, a compound represented by formula (1), a compound represented by formula (2) or (3), and a compound represented by formula (4), and the color developing agent has a concentration of 0.02 to 0.2 mol/l, the sulfite has a concentration meeting the following requirement: 0.1<sulfite concentration (mol/l)/color developing agent concentration (mol/l)<10, the compound of formula (2) or (3) has a molar ratio of the compound of formula (2) or (3) to the compound of formula (1) of 0.01 to 0.1, and the compound of formula (4) is present in an amount of 1 to 50 g/l, HO—N—(X-A) 2 formula (1) wherein X is an alkylene group, which may be substituted; A is a carboxyl group, sulfo group, phosphono group, hydroxy group, alkoxy group, amino group, ammonio group, sulfamoyl group or sulfamoyl group, HO—NH—X-A formula (2) Y—R—SO 3 M formula (3) wherein X and A are the same as defined in formula (1); Y is a hydroxy group, a halogen atom, an alkoxy group, a sulfo group or a sulfonate group, a sulfuric ester group or sulfate ester, or a sulfonyl halide; R is an alkylene group having 1 to 5 carbon atoms; M is Li, Na, K or NH 4 , HO—(R—O) n —H formula (4) wherein R is —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —, or —CH 2 —CH(CH 3 )—; and n is an integer of 1 to 30.