1. Introduction to digital inkjet printing ink

 

Inkjet printing systems are mainly divided into two types based on different principles. One is an inkjet printing machine produced using micro-piezoelectric technology using CAD/CAM software provided by Sophis, and the other is an inkjet printing machine produced using the principle of hot pressing. The former is suitable for reactive dyes and disperse dyes, and the latter is suitable for acid dyes. Domestic printing and dyeing factories have purchased several sets of digital inkjet printing machines, mainly the printing system produced by Japan's MIMAKI Company and the A'TEX PRINT TEX-1300/1600 digital inkjet printing machine produced by Hangzhou Honghua Company. Both of these printing machines are produced using the piezoelectric principle.

 

Digital inkjet printing technology has been used in the production process of printing and dyeing factories. Seiren is currently the largest fabric printing company in Japan. It has built its own inkjet printing production system. Its digital printing products produced using reactive dyes, disperse dyes, and acid dyes are already on the market.

 

2. Ink for digital inkjet printing

 

There are two ways of digital inkjet printing. One is YMCIC inkjet printing based on high-precision nozzles, that is, dot matrix printing; the other is pre-mixing, which pre-mixes the dyes into a certain color and sprays them onto the fabric. When applying the YMCK method for printing, in order to obtain high fineness and smooth light transition colors, high resolution (high mountain p) must be used, which requires the fineness of the nozzle to be very small, and the requirements for ink are also very high. It is difficult to increase the inkjet speed, but the number of dyes used is relatively small, and the basic colors are four colors. The pre-mixing method does not require high nozzle fineness. 180dP can meet general requirements, and 360dP can obtain very fine printing effects. The printed products are close to the style of plate printing. Due to the large nozzle diameter, the requirements for dyes are not high. In the future, digital inkjet printing will develop in these two directions to meet the different requirements of users.

 

1. YMCK inkjet printing ink

 

YMCK is a widely used printing method. The inkjet printing machines sold on the market are also mainly designed for this purpose. Since the nozzle diameter of the nozzle is very small and the printing resolution is high, the viscosity, surface tension, inorganic salt content and particle fineness of the dye are very high. The world's major dye companies and companies producing inkjet printing machines have all developed inks for inkjet printing. Ciba Specialty Chemicals has applied for a patent for active dye inks for inkjet printing. Active dyes containing active groups such as monochlorotriazine and monofluorotriazine ethyl alum sulfate are used for digital inkjet printing inks. First, the inorganic salts in the dyes are removed by membrane separation methods such as ultrafiltration and reverse osmosis. 1,2-propanol or N-methyl-2-pyrrolidone are used as solubilizing solvents, methyl cellulose, ethyl cellulose or alginate are used as thickeners, and PH buffers and mildew inhibitors are added to make inkjet inks. Printing with a micro-piezoelectric inkjet printing machine has achieved good results. Canon has applied for a patent for the preparation of disperse dye inkjet inks, which can be used for fabric printing using a thermal foaming inkjet printer.

 

Pigment-based inkjet printing inks are also a focus of recent development. These inks can be used for various fibers and their blended fabrics, do not require fabric pretreatment, and can achieve satisfactory color fastness.