Patent ID: 7172854

Claim:
A color developer solution comprising p-phenylenediamine color developing agents, wherein 2% to 35% by weight of the p-phenylenediamine color developing agents is accounted for by a N-hydroxyalkyl-substituted p-phenylenediamine color developing agent, and the color developer solution further comprising a compound represented by the following formula (1) or (2): wherein R is a hydrogen atom or an alkyl group; L is an alkylene group; A is a carboxyl group, a sulfo group, a phosphono group, a phosphine group, a hydroxyl group, an amino group, an ammonio group, a carbamoyl group, a sulfamoyl group, an alkylsulfonyl group, an alkoxyl group or â€”O Bâ€”O n â€”Râ€² in which Râ€² is a hydrogen atom or an alkyl group, B is an alkylene group and n is an integer of 1 to 4; wherein Râ€³ and Râ€³â€² are each independently a saturated or unsaturated aliphatic hydrocarbon group having from 1 to 6 carbon atoms, a cycloalkylene group or an arylene group; m is an integer of 4 to 50,000; and p is 0 or an integer of 1 to 10 wherein the color developer solution comprises the p-phenylenediamine color developing agents in an amount of from 1.4Ã—10âˆ’2 to 2.5Ã—10âˆ’2 mol/l.