Experimental Study on Fabric Inkjet Printing and Its Ink System (I)

【Abstract】Inkjet printing is the latest fabric printing technology that emerged in the last few years of this century and has the most promising applications. In this paper, the basic principle and method of ink jet printing are discussed from the equipment and technology of fabric inkjet printing test. The main technical requirements of polymer ink system, microlatex two-phase ink system and modified dye ink system are studied and studied. Basic composition, and tested the ink system printing performance of the fabric.

[Descriptor] Principle of Jet Printing Method System Textile ink printing paddle

introduction

It has been thought in the past that fabric printing is a process in which a dye or pigment is patterned on a fabric in accordance with a predetermined set of intentions. In this process, the intent of the setting is first transferred to the screen or drum to form a negative pattern; then the dye or pigment is passed (passed) through the screen or roller to the fabric, and the pigment is fixed after the post-treatment. And have a certain fastness properties. This kind of processing must take every step of the design, such as color separation, drafting, drafting, color proofing, and post-printing, which are time consuming and expensive. Since STORK, a Dutch company, invented rotary screen printing in the 1960s, there has been little progress in printing technology (process and process), and the production cycle still takes 4-16 weeks. At present, the world market share in fabric printing has gradually increased, with an annual output of approximately 23 billion square meters, of which 90% are processed by screens. Traditional fabric printing methods have become the major bottleneck between production and trade. In recent years, digital inkjet technology has caused profound changes in the printing industry and has been successfully implemented, which suggests that people can apply similar technologies for ink jet printing to fabric printing. This greatly eliminates the need for traditional fabric printing processes and allows easy storage and transfer of patterns in computer files; the use of an ink/toner equivalent to a paint paste to achieve instant, fast response speeds Mass production until mass production. This ink-jet printing technology will bring about significant changes to the traditional fabric printing process technology, and has a huge potential for development.

The so-called digital inkjet printing, the ink (or called toner) driven by the compressed air, through the nozzle continuously sprayed onto the printed fabric, the computer controlled pattern formation. As early as the 1970s, the British ICI company had conducted "multicolor dyeing" studies; in the 1980s, Australia's CSIRO developed the "diffuse jet" technology; since the 1990s, Japan CANON, SEIREN and the Netherlands STORK have made some new and effective results, respectively. Inkjet printing research.

CANON printing machine has 8 print heads, each print head has 170 nozzles, a total of 1360 nozzles, printing width is 1600mm, printing resolution is 360 dpi (14. 2 dots/mm), printing speed is 0.86 m /min. The system uses active/acid/disperse dye aqueous inks that are suitable for cotton, silk/nylon and polyester fabrics, respectively. The system uses 8 sets of colors; 3 sets of primary colors - cyan, magenta, yellow, 1 set of black, 4 sets of special colors.

SEIREN is the largest fabric printing company in Japan and has formed its own inkjet production system. It has been reported that its use of reactive and disperse dyestuffs has been successfully printed on cotton, silk, polyester and polyamide fabrics, and it has begun to supply fabric products with digital print marks.

STORK company is currently working with several companies in the European Community to study the function of the program, its goal is to make the printing speed from the current nearly 1 m/min, increased by 20 times; refer to the ISO standard, the light fastness of 3-4 Grade, wash fastness 4; reduce the amount of color to the existing half, that is, using only 3 sets of primary colors and 1 set of black.

In addition, the “garment jet printing” machine has been exhibited for the first time at the “ITITI” in Milan, Italy. It uses 4 sets of multi-nozzle print heads (Cyan, Magenta, Yellow and Black) with 10 print heads each. Nozzles, 0. 99 mm apart, print speed 6.4 m/h.

This article will discuss the use of 1MAJE S4 inkjet printing machine for inkjet printing process conditions, the type of ink (or toner) and formula, and the impact of the ink system on the printing effect of the fabric.

2 test equipment and methods

The equipment used in this study was the IMAJE S4 inkjet printer manufactured by TOXOT of France for ink formulation experiments. Figure 1 shows the printhead schematic and working principle of the IMAJE S4 inkjet printing tester.

Figure I IJJE S4 inkjet printer print head schematic and working principle

1 ink; 2-nozzle; 3 a piezoelectric crystal (resonator); 4 a charge electrode; 5-detection electrode; 6-deflection electrode; 7 a recovery tank; 8 a printed fabric

The ink (1) propelled by compressed air (with a pressure of about 300 kPa) emerges from a nozzle (2) with a diameter of 10-100 μm and is mechanically excited by the piezoelectric crystal (resonator) (3) with high-frequency oscillation. A stream of ink droplets of 62,500 droplets per second at a speed of 18-20 m/s was formed and broken into regularly controlled droplets. In order to form the designed pattern, the charge electrode (4) is controlled by the computer to apply or not to charge the droplets according to the position and color shade of the pattern. The charge amount is determined by the detection electrode (5), and the charge amount is insufficient to feedback. Charge the system. When a charged or uncharged droplet jet passes through the deflection electrode (6), the charged droplets are deflected by different distances depending on the amount of charged energy, landed on the fabric (8) to form a pattern, and the uncharged droplets are still running in a straight line. , Fall into a negative pressure holding tank (7), these droplets can still be recycled and reused (this study is not recycled). Each nozzle can control droplets in 30 different locations. This is called continuous inkjet printing (CIJ) technology.

Continuous inkjet printing also uses uncharged droplets for printing, while charged droplets are collected for recycling. However, the need to increase a lot of nozzles to get the width of the need to print, but also can not ideally solve the cost and reliability issues.

Another type of ink jet printing technology is called the drop-in-drop (DOD) method, where only one drop of ink is supplied when printing is required. The ink droplets are generated by means of thermal pulsation (boiling jet generation), that is, a resistor is heated by a computer signal to a certain high temperature to cause the ink to produce misty bubbles that cool and burst to form ink droplets that are ejected from the nozzles. The cycle time is defined as 10,000 droplets/s, and the droplet volume is about 150-220 μl. Therefore, the single thermal ink nozzle consumes about 0.1 mL/min. The high temperature (>350°C) required for the rapid ejection of the droplets causes the decomposition of the ink on the resistor, resulting in heat transfer or nozzle clogging. The advantage is that the assembly cost of the nozzle is low, but the reliability is poor and the printing speed is slower.