Patent ID: 7301011

Claim:
An azo compound or tautomer thereof represented by the following formula (1): wherein R 1 , R 2 , R 5 , R 7 , and R 8 each independently represents a hydrogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, alkylsulfonyl group, arylsulfonyl group, alkylthio group, arylthio group, cyano group, acyl group, carbamoyl group, amino group, nitro group, or halogen atom; R 3 and R 4 each independently represents a hydrogen atom, alkyl group, or aryl group; each of R 6 and R 9 is an aryl group; and R 1 and R 2 , R 2 and R 3 , R 3 and R 4 , R 6 and R 7 , R 7 and R 8 , and R 8 and R 9 may join to each other to form a ring structure; and A − represents a counter anion.