Black ink set and ink jet recording method using the same

Year	Description
2001	Invention patented by Jun Ito and Miharu Kanaya on July 26th, 2001. Abstract: A black ink set is provided which, in a middle to high lightness region of images, can improve image quality, especially lightfastness and gradation, and can reduce graininess. The black ink set comprises at least a first black ink composition and a second black ink composition, wherein the first black ink composition has a lightness (L) in the range of 1 to 30 as calculated from the spectral transmittance of a 1000-fold dilution of the first black ink composition and the second black ink composition has an L value in the range of 35 to 80 as calculated from the spectral transmittance of a 1000-fold dilution of the second black ink composition and contains a compound represented by formula (I) as a colorant: ##STR1## wherein R represents a C.sub.1-6 alkyl group, a hydroxyl group, or a group -NR.sup.1 R.sup.2 in which R.sup.1 and R.sup.2 each independently represent a hydrogen atom or a C.sub.1-6 alkyl group; and M represents an alkali metal or a group -NR.sup.1 R.sup.2 in which R.sup.1 and R.sup.2 each independently represent a hydrogen atom or a C.sub.1-6 alkyl group.
Source: selected by the editor from original sources.

Invention: Black ink set and ink jet recording method using the same