| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a pigment for black ink which is stable even when a high-concentration dye aqueous solution and an ink are stored for a long period of time with high solubility to a medium including water as an essential component, provides high density in printed image, gives a black recorded image excellent in toughness of printed image, particularly, water resistance, light resistance and ozone gas resistance, and further is easy to synthesize and inexpensive, and an ink composition using the same. <P>SOLUTION: The azo compound represented by formula (1) or a salt thereof is provided, wherein A represents nitro-substituted phenyl, R<SP POS="POST">1</SP>, R<SP POS="POST">2</SP>, R<SP POS="POST">4</SP>, R<SP POS="POST">5</SP>and R<SP POS="POST">6</SP>each independently represent hydrogen atom, halogen atom, cyano, hydroxyl, carboxy, sulfo or the like, R<SP POS="POST">3</SP>represnts hydrogen atom, halogen atom, cyano, carboxy, nitro or the like, n represents 0 or 1, a and b each represent a substituting position of carboxy group, and * represents a bonding position of azo group. <P>COPYRIGHT: (C)2013,JPO&INPIT |
