Study On Digital Ink-jet Printing Technology Of Reactive Dyes

The digital ink-jet printing is a new-style printing technology, which integratesinformation process, computer image processing, electronics and new materials. It iscompatible with the checkered rhythm of market and production requirements for energyconservation and emission reduction because of its advantages over traditional printingtechnology in speediness, flexibility, cleanness, eco-friendliness and creativity. Under thecurrent technical conditions, the use of some new research methods and processtechnologies can create a positive development for ink-jet technology. In this paper, theinks of reactive dyes were used to the ink-jet printing of silk and cotton and the differenceof printing properties between silk and cotton was discussed. Furthermore, with the aim ofdecreasing the high mangle expression in the process of sizing and the poor colorrepeatability of printed fabrics, the foam sizing technology as well as the dependence ofthe color repeatability of fabrics on the humidity and temperature of the environmentwhere printed fabrics are deposited was investigated. The important conclusions wereconcluded as follows:(a) The color depth of fabrics increased with an increase in the dosage of thickener;the use of sodium bicarbonate as an alkaline agent displayed the satisfactory results in theaspects of color depth and color stability; in order to achieve the satisfactory color depth,cotton fabric needed higher alkali and urea dosages than silk fabric, but showed nodifference of sodium sulfate dosage as compared with silk fabric; in the process of thesteaming after inkjet printing, the degree of the fixation of reactive dyes to cotton waslower than that to silk, but the rate of the fixation of dyes to cotton was faster than that tosilk.(b) With increasing dosage of thickener, the foamability of foam sizing solutiondecreased, but the foam stability increased; high temperature enhanced foamability anddecreased foam stability; the addition of alkali, urea and neutral electrolyte in foam sizingsolution had no obvious effect on the foamability, but decreased markedly the foam stability. The printing effect of cotton fabric was more remarkably affected by sizingparameters than that of silk fabric. Foam sizing showed the merits of lower mangleexpression and energy consumption in comparison with conventional sizing technique, andalso gave good picture sharpness and color fastness.(c) During a period between ink-jet printing and steaming, an increase in thedepositing humidity and temperature of printed fabrics increased the color depth of silkfabric because of the high extent of the reaction of reactive dyes with silk fiber, but thesimilar effect was minor for printed cotton fabric. The good control of printed fabrics instorage humidity and temperature is important for color repeatability.