Inkjet printing has become the new frontier in textile printing, offering advantages in process efficiency, ease of use, cost effectiveness and environmental impact [1]. Effective use of inkjet technology with dyes requires fabric pretreatment with auxiliaries such as thickener, urea and alkali, since they cannot be used in inkjet inks as they may adversely affect the printhead and the ink properties. Inkjet inks for textiles use dyes selected from those already commercially available. These inks are formulated from conventional dyes with further purification to ensure good compatibility with the printhead and to increase the ink shelf lifetime. Inkjet formulation also involves simultaneous adjustment of the ink rheological behaviour. The ideal inkjet ink should exhibit Newtonian behaviour with a constant viscosity under increasing shear rate [2]. The main ingredients which the ink may contain are humectant, surfactant, buffer, co-solvents, viscosity modifier, dye solubiliser, UV-blocker, and anti-oxidant [3]. Chemical selection depends to an extent on the substrate and printhead type. The main inkjet printhead type currently used in textile printers is piezo drop-on-demand (DOD). Viscosity, surface tension, pH, conductivity, evaporation rate, dissolved oxygen content and purity requirements all vary according to the printhead type. For a DOD printhead, the general guidelines are viscosity <12 cp and surface tension >32 N m~(-1). The pH is selected according to the colorant. For example, strongly alkaline conditions are avoided with reactive dyes to minimise dye hydrolysis, while acidic conditions can cause printhead corrosion. Typically, the pH of inks containing reactive dyes should be in the range 6.5-8. Ink evaporation is a crucial characteristic of water-based inkjet inks since it has a major effect on the generation of the first drop. After a long idle period, the printhead may encounter difficulties in ejecting ink droplets, giving rise to misdirection, velocity change or no droplet at all. The evaporation rate can be modified with a humectant. A dissolved oxygen content < 4 mg/g is desirable for a DOD printhead to ensure optimum ink compressibility and is achieved commonly by degassing or ultrasonication.
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机译：喷墨印花已成为纺织印刷的新前沿，提供工艺效率，易用性，成本效益和环境影响的优势[1]。用染料的喷墨技术有效地使用织物预处理，助剂如增稠剂，尿素和碱，因为它们不能用于喷墨油墨，因为它们可能对打印头和油墨性质产生不利影响。用于纺织品的喷墨油墨使用从已商购的染料使用。这些油墨配制由常规染料，进一步纯化，以确保与打印头的良好兼容性，并增加墨水搁板寿命。喷墨制剂还涉及同时调整油墨流变行为。理想的喷墨墨水应表现出牛顿行为，在增加剪切速率下恒定粘度[2]。油墨可含有的主要成分是保湿剂，表面活性剂，缓冲液，共溶剂，粘度改性剂，染料溶解剂，UV-嵌体和抗氧化剂[3]。化学选择取决于基板和打印头型的程度。目前用于纺织品打印机的主要喷墨打印头类型是压电按需（DOD）。粘度，表面张力，pH，导电性，蒸发速率，溶解氧含量和纯度要求根据打印头型而变化。对于DOD打印头，一般指南是粘度<12cc和表面张力> 32 n m〜（-1）。根据着色剂选择pH。例如，用活性染料避免了强烈碱性条件，以最大限度地减少染料水解，而酸性条件会导致打印头腐蚀。通常，含有反应性染料的油墨的pH应在6.5-8的范围内。墨水蒸发是水基喷墨油墨的关键特征，因为它对第一滴的产生具有重大影响。在怠速长时间之后，打印头可能在弹出墨滴时遇到困难，从而产生误导，速度变化或根本没有液滴。蒸发速率可以用保湿剂修饰。溶解的氧含量<4mg / g是期望的，用于DOD打印头，以确保最佳油墨可压缩性，并且通过脱气或超声脱气而常见。
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