This invention relates to metal complex dyes that are free of chromium, are not carcinogenic, mutagenic, or reproductive toxins. These dyes have good solubility and conductivity in organic solvents, chemical stability, and light stability. The invention also relates to a method of inkjet printing comprising using the ink compositions and ink cartridges.

This invention relates to metal complex dyes that are free of chromium, are not carcinogenic, mutagenic, or reproductive toxins. These dyes have good solubility and conductivity in organic solvents, chemical stability, and light stability. The invention also relates to a method of inkjet printing comprising using the ink compositions and ink cartridges.

An azo iron complex dye which does not contain harmful heavy metals, exhibits sufficient solubility in organic solvents for practical use, and exhibits an excellent black color. The azo iron complex dye contains a disazo-monoazo iron complex represented by the following chemical formula (1)

##STR00001## (in the chemical formula (1), R.sup.1 and R.sup.2 are each independently a straight or branched alkyl group having 3-10 carbon atoms, R.sup.3 is an electron-withdrawing group, R.sup.4 is a straight or branched alkyl group having 1-5 carbon atoms or a straight or branched alkoxy group having 1-5 carbon atoms, R.sup.5 is a nitro group, a sulfonamide group or a halogen atom, R.sup.6 is a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a nitro group or a halogen atom, R.sup.7 is a hydrogen atom or a straight or branched alkyl group having 3-12 carbon atoms, and A.sup.+ is a monovalent cation).

An azo iron complex dye which does not contain harmful heavy metals, exhibits sufficient solubility in organic solvents for practical use, and exhibits an excellent black color. The azo iron complex dye contains a disazo-monoazo iron complex represented by the following chemical formula (1)

##STR00001## (in the chemical formula (1), R.sup.1 and R.sup.2 are each independently a straight or branched alkyl group having 3-10 carbon atoms, R.sup.3 is an electron-withdrawing group, R.sup.4 is a straight or branched alkyl group having 1-5 carbon atoms or a straight or branched alkoxy group having 1-5 carbon atoms, R.sup.5 is a nitro group, a sulfonamide group or a halogen atom, R.sup.6 is a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a nitro group or a halogen atom, R.sup.7 is a hydrogen atom or a straight or branched alkyl group having 3-12 carbon atoms, and A.sup.+ is a monovalent cation).

An azo iron complex dye which does not contain harmful heavy metals, exhibits sufficient solubility in organic solvents for practical use, and exhibits an excellent black color. The azo iron complex dye contains a disazo-monoazo iron complex represented by the following chemical formula (1) ##STR00001##
(in the chemical formula (1), R.sup.1 and R.sup.2 are each independently a straight or branched alkyl group having 3-10 carbon atoms, R.sup.3 is an electron-withdrawing group, R.sup.4 is a straight or branched alkyl group having 1-5 carbon atoms or a straight or branched alkoxy group having 1-5 carbon atoms, R.sup.5 is a nitro group, a sulfonamide group or a halogen atom, R.sup.6 is a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a nitro group or a halogen atom, R.sup.7 is a hydrogen atom or a straight or branched alkyl group having 3-12 carbon atoms, and A.sup.+ is a monovalent cation).

An azo iron complex dye which does not contain harmful heavy metals, exhibits sufficient solubility in organic solvents for practical use, and exhibits an excellent black color. The azo iron complex dye contains a disazo-monoazo iron complex represented by the following chemical formula (1) ##STR00001##
(in the chemical formula (1), R.sup.1 and R.sup.2 are each independently a straight or branched alkyl group having 3-10 carbon atoms, R.sup.3 is an electron-withdrawing group, R.sup.4 is a straight or branched alkyl group having 1-5 carbon atoms or a straight or branched alkoxy group having 1-5 carbon atoms, R.sup.5 is a nitro group, a sulfonamide group or a halogen atom, R.sup.6 is a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a nitro group or a halogen atom, R.sup.7 is a hydrogen atom or a straight or branched alkyl group having 3-12 carbon atoms, and A.sup.+ is a monovalent cation).