Low toxicity ink formulations with improved printhead lifetime

An inkjet ink comprising:

• (i) a disazo dye of formula (I):
• wherein:
• A is a C6-14 aryl group having 0, 1, 2, 3, 4 or 5 substituents selected from the group consisting of:
• —SO3M, nitro, carboxyl, halogen, hydroxyl, amino, C1-4 alkylamino, C1-4 alkoxy, C1-4 alkyl, C1-4 haloalkyl, cyano, sulfonamide, carbamoyl, C1-4 alkylamido and C1-4 alkoxycarbonyl;
• B is a C6-14 aryl group having 0, 1, 2, 3, 4 or 5 substituents selected from the group consisting of:
• —SO3M, nitro, carboxyl, halogen, hydroxyl, amino, C1-4 alkylamino, C1-4 alkoxy, C1-4 alkyl, C1-4 haloalkyl, cyano, sulfonamide, carbamoyl, C1-4 alkylamido and C1-4 alkoxycarbonyl;
• each M is independently selected from the group consisting of:
• hydrogen, lithium, sodium, potassium, ammonium and quaternary ammonium;
• and the dye of formula (I) comprises at least 3 groups of formula —SO3M;
• (ii) 1,3-propanediol;
• (iii) a glycol compound selected from the group consisting of:
• triethylene glycol and tetraethylene glycol;
• and
• (iv) water,
• wherein an amount of 1,3-propanediol or the glycol compound is greater than an amount of any other co-solvent in the ink.