Dyes for Ink-Jet Application

Generally, ink dyes for ink jet applications and writing, drawing, or marking materials are selected from food, acid, direct, sulfur, and reactive dyes. The choice of dye depends on the application and the ink used, whether it is aqueous, solvent based, or hot melt, and on the printer type continuous ink jet or drop-on-demand, piezo or thermal inkjet. 

Irrespective of the printer and solvent system, ink jet dyes have to meet specific requirements [2], some of which are listed in Table 5.8. 

Fastness high light, water, and smear fastness 

In a first phase of developing ink-jet dyes, commercially available paper, leather, and textile dyes were selected and purified. However, considerable research has been invested in meeting the specific requirements of ink jets, and novel black dyes for monochrome printing and yellow, magenta, and cyan dyes for color printing have been introduced to the market [6], 

Black Dyes. Water-soluble black ink jet dyes are selected from disazo, polyazo, metal complex, and sulfur dyes [7], For ink-jet systems using the piezo technology, C.I. Direct Black 19, 35255 [6428-31-5] and DirectBlack 154,303865 [54804-85-2 are used. Food Black 2, 27755 [.2118-39-0] was selected for thermal ink-jet printers due to its thermal stability, but this dye exhibits a poor waterfastness. Replacing the sulfo groups by carboxyl groups gave C.I. DirectBlack 195 (1), which has been introduced in commercial printers and shows much improved waterfastness due to pH-dependant differential solubility [3], 

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Bauer, W. and Ritter, J., Tailoring Dyes for Ink-Jet Applications , in Z. Yoshida and Y. Shirota, Editors, Chemistry of Functional Dyes, Chapter 8.1, p. 649, Mita, Tokyo, 1993. 

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